{"collection":"philosophy-ethics","full_text_available":true,"graph_url":"https://unchartedknowledge.5gfusion.net/v2/api/page/gutenberg_29869/graph","html_url":"https://unchartedknowledge.5gfusion.net/v2/page/gutenberg_29869","id":"gutenberg_29869","license":"Public Domain (US)","rights_basis":"gutenberg_metadata_copyright_false","source":"gutenberg","source_url":"https://www.gutenberg.org/ebooks/29869","summary":null,"tags":["Category: Essays, Letters & Speeches","Category: Philosophy & Ethics","Category: Politics","Category: Science - Biology","Philosophy","Political science","Science"],"text":"Produced by Adrian Mastronardi, Carla Foust, and the Online\nDistributed Proofreading Team at https://www.pgdp.net (This\nfile was produced from images generously made available\nby The Internet Archive/Canadian Libraries)\n\n\n\n\n\nTranscriber's note\n\n\nMinor punctuation errors have been changed without notice. Printer\nerrors have been changed and are listed at the end. All other\ninconsistencies are as in the original.\n\n\n\n\nESSAYS:\n\nSCIENTIFIC, POLITICAL, & SPECULATIVE.\n\n\nBY\n\nHERBERT SPENCER.\n\n\nLIBRARY EDITION,\n\n(OTHERWISE FIFTH THOUSAND)\n\n_Containing Seven Essays not before Republished, and various other\nadditions._\n\n\nVOL. I.\n\n\n   WILLIAMS AND NORGATE,\n   14, HENRIETTA STREET, COVENT GARDEN, LONDON:\n   AND 20. SOUTH FREDERICK STREET. EDINBURGH.\n   1891.\n\n\n\n\n   LONDON:\n   G. NORMAN AND SON, PRINTERS, HART STREET,\n   COVENT GARDEN.\n\n\n\n\nPREFACE\n\n\nExcepting those which have appeared as articles in periodicals during\nthe last eight years, the essays here gathered together were originally\nre-published in separate volumes at long intervals. The first volume\nappeared in December 1857; the second in November 1863; and the third in\nFebruary 1874. By the time the original editions of the first two had\nbeen sold, American reprints, differently entitled and having the essays\ndifferently arranged, had been produced; and, for economy's sake, I have\nsince contented myself with importing successive supplies printed from\nthe American stereotype plates. Of the third volume, however, supplies\nhave, as they were required, been printed over here, from plates partly\nAmerican and partly English. The completion of this final edition of\ncourse puts an end to this make-shift arrangement.\n\nThe essays above referred to as having been written since 1882, are now\nincorporated with those previously re-published. There are seven of\nthem; namely--\"Morals and Moral Sentiments,\" \"The Factors of Organic\nEvolution,\" \"Professor Green's Explanations,\" \"The Ethics of Kant,\"\n\"Absolute Political Ethics,\" \"From Freedom to Bondage,\" and \"The\nAmericans.\" As well as these large additions there are small additions,\nin the shape of postscripts to various essays--one to \"The Constitution\nof the Sun,\" one to \"The Philosophy of Style,\" one to \"Railway Morals,\"\none to \"Prison Ethics,\" and one to \"The Origin and Function of Music:\"\nwhich last is about equal in length to the original essay. Changes have\nbeen made in many of the essays: in some cases by omitting passages and\nin other cases by including new ones. Especially the essay on \"The\nNebular Hypothesis\" may be named as one which, though unchanged in\nessentials, has been much altered by additions and subtractions, and by\nbringing its statements up to date; so that it has been in large measure\nre-cast. Beyond these respects in which this final edition differs from\npreceding editions, it differs in having undergone a verification of its\nreferences and quotations, as well as a second verbal revision.\n\nNaturally the fusion of three separate series of essays into one series,\nhas made needful a general re-arrangement. Whether to follow the order\nof time or the order of subjects was a question which presented itself;\nand, as neither alternative promised satisfactory results, I eventually\ndecided to compromise--to follow partly the one order and partly the\nother. The first volume is made up of essays in which the idea of\nevolution, general or special, is dominant. In the second volume essays\ndealing with philosophical questions, with abstract and concrete\nscience, and with aesthetics, are brought together; but though all of\nthem are tacitly evolutionary, their evolutionism is an incidental\nrather than a necessary trait. The ethical, political, and social essays\ncomposing the third volume, though mostly written from the evolution\npoint of view, have for their more immediate purposes the enunciation of\ndoctrines which are directly practical in their bearings. Meanwhile,\nwithin each volume the essays are arranged in order of time: not indeed\nstrictly, but so far as consists with the requirements of sub-classing.\n\nBeyond the essays included in these three volumes, there remain several\nwhich I have not thought it well to include--in some cases because of\ntheir personal character, in other cases because of their relative\nunimportance, and in yet other cases because they would scarcely be\nunderstood in the absence of the arguments to which they are replies.\nBut for the convenience of any who may wish to find them, I append their\ntitles and places of publication. These are as follows:--\"Retrogressive\nReligion,\" in _The Nineteenth Century_ for July 1884; \"Last Words about\nAgnosticism and the Religion of Humanity,\" in _The Nineteenth Century_\nfor November 1884; a note to Prof. Cairns' Critique on the _Study of\nSociology_, in _The Fortnightly Review_, for February 1875; \"A Short\nRejoinder\" [to Mr. J. F. McLennan], _Fortnightly Review_, June 1877;\n\"Prof. Goldwin Smith as a Critic,\" _Contemporary Review_, March 1882; \"A\nRejoinder to M. de Laveleye,\" _Contemporary Review_, April 1885.\n\nLONDON, _December, 1890_.\n\n\n\n\nCONTENTS OF VOL. I.\n\n\n                                                                    PAGE\n\n   THE DEVELOPMENT HYPOTHESIS                                          1\n\n   PROGRESS: ITS LAW AND CAUSE                                         8\n\n   TRANSCENDENTAL PHYSIOLOGY                                          63\n\n   THE NEBULAR HYPOTHESIS                                            108\n\n   ILLOGICAL GEOLOGY                                                 192\n\n   BAIN ON THE EMOTIONS AND THE WILL                                 241\n\n   THE SOCIAL ORGANISM                                               265\n\n   THE ORIGIN OF ANIMAL WORSHIP                                      308\n\n   MORALS AND MORAL SENTIMENTS                                       331\n\n   THE COMPARATIVE PSYCHOLOGY OF MAN                                 351\n\n   MR. MARTINEAU ON EVOLUTION                                        371\n\n   THE FACTORS OF ORGANIC EVOLUTION                                  389\n\n\n   (_For Index, see Volume III._)\n\n\n\n\nTHE DEVELOPMENT HYPOTHESIS.\n\n    [_Originally published in _The Leader, _for March 20,_ 1852. _Brief\n    though it is, I place this essay before the rest, partly because\n    with the exception of a similarly-brief essay on \"Use and Beauty\",\n    it came first in order of time, but chiefly because it came first in\n    order of thought, and struck the keynote of all that was to\n    follow._]\n\n\nIn a debate upon the development hypothesis, lately narrated to me by a\nfriend, one of the disputants was described as arguing that as, in all\nour experience, we know no such phenomenon as transmutation of species,\nit is unphilosophical to assume that transmutation of species ever takes\nplace. Had I been present I think that, passing over his assertion,\nwhich is open to criticism, I should have replied that, as in all our\nexperience we have never known a species _created_, it was, by his own\nshowing, unphilosophical to assume that any species ever had been\ncreated.\n\nThose who cavalierly reject the Theory of Evolution as not being\nadequately supported by facts, seem to forget that their own theory is\nsupported by no facts at all. Like the majority of men who are born to a\ngiven belief, they demand the most rigorous proof of any adverse belief,\nbut assume that their own needs none. Here we find, scattered over the\nglobe, vegetable and animal organisms numbering, of the one kind\n(according to Humboldt), some 320,000 species, and of the other, some\n2,000,000 species (see Carpenter); and if to these we add the numbers of\nanimal and vegetable species which have become extinct, we may safely\nestimate the number of species that have existed, and are existing, on\nthe Earth, at not less than _ten millions_. Well, which is the most\nrational theory about these ten millions of species? Is it most likely\nthat there have been ten millions of special creations? or is it most\nlikely that, by continual modifications due to change of circumstances,\nten millions of varieties have been produced, as varieties are being\nproduced still?\n\nDoubtless many will reply that they can more easily conceive ten\nmillions of special creations to have taken place, than they can\nconceive that ten millions of varieties have arisen by successive\nmodifications. All such, however, will find, on inquiry, that they are\nunder an illusion. This is one of the many cases in which men do not\nreally believe, but rather _believe they believe_. It is not that they\ncan truly conceive ten millions of special creations to have taken\nplace, but that they _think they can do so_. Careful introspection will\nshow them that they have never yet realized to themselves the creation\nof even _one_ species. If they have formed a definite conception of the\nprocess, let them tell us how a new species is constructed, and how it\nmakes its appearance. Is it thrown down from the clouds? or must we hold\nto the notion that it struggles up out of the ground? Do its limbs and\nviscera rush together from all the points of the compass? or must we\nreceive the old Hebrew idea, that God takes clay and moulds a new\ncreature? If they say that a new creature is produced in none of these\nmodes, which are too absurd to be believed, then they are required to\ndescribe the mode in which a new creature _may_ be produced--a mode\nwhich does _not_ seem absurd; and such a mode they will find that they\nneither have conceived nor can conceive.\n\nShould the believers in special creations consider it unfair thus to\ncall upon them to describe how special creations take place, I reply\nthat this is far less than they demand from the supporters of the\nDevelopment Hypothesis. They are merely asked to point out a\n_conceivable_ mode. On the other hand, they ask, not simply for a\n_conceivable_ mode, but for the _actual_ mode. They do not say--Show us\nhow this _may_ take place; but they say--Show us how this _does_ take\nplace. So far from its being unreasonable to put the above question, it\nwould be reasonable to ask not only for a _possible_ mode of special\ncreation, but for an _ascertained_ mode; seeing that this is no greater\na demand than they make upon their opponents.\n\nAnd here we may perceive how much more defensible the new doctrine is\nthan the old one. Even could the supporters of the Development\nHypothesis merely show that the origination of species by the process of\nmodification is conceivable, they would be in a better position than\ntheir opponents. But they can do much more than this. They can show that\nthe process of modification has effected, and is effecting, decided\nchanges in all organisms subject to modifying influences. Though, from\nthe impossibility of getting at a sufficiency of facts, they are unable\nto trace the many phases through which any existing species has passed\nin arriving at its present form, or to identify the influences which\ncaused the successive modifications; yet, they can show that any\nexisting species--animal or vegetable--when placed under conditions\ndifferent from its previous ones, _immediately begins to undergo certain\nchanges fitting it for the new conditions_. They can show that in\nsuccessive generations these changes continue; until, ultimately, the\nnew conditions become the natural ones. They can show that in cultivated\nplants, in domesticated animals, and in the several races of men, such\nalterations have taken place. They can show that the degrees of\ndifference so produced are often, as in dogs, greater than those on\nwhich distinctions of species are in other cases founded. They can show\nthat it is a matter of dispute whether some of these modified forms are\nvarieties or separate species. They can show, too, that the changes\ndaily taking place in ourselves--the facility that attends long\npractice, and the loss of aptitude that begins when practice ceases--the\nstrengthening of passions habitually gratified, and the weakening of\nthose habitually curbed--the development of every faculty, bodily,\nmoral, or intellectual, according to the use made of it--are all\nexplicable on this same principle. And thus they can show that\nthroughout all organic nature there _is_ at work a modifying influence\nof the kind they assign as the cause of these specific differences: an\ninfluence which, though slow in its action, does, in time, if the\ncircumstances demand it, produce marked changes--an influence which, to\nall appearance, would produce in the millions of years, and under the\ngreat varieties of condition which geological records imply, any amount\nof change.\n\nWhich, then, is the most rational hypothesis?--that of special creations\nwhich has neither a fact to support it nor is even definitely\nconceivable; or that of modification, which is not only definitely\nconceivable, but is countenanced by the habitudes of every existing\norganism?\n\nThat by any series of changes a protozoon should ever become a mammal,\nseems to those who are not familiar with zoology, and who have not seen\nhow clear becomes the relationship between the simplest and the most\ncomplex forms when intermediate forms are examined, a very grotesque\nnotion. Habitually looking at things rather in their statical aspect\nthan in their dynamical aspect, they never realize the fact that, by\nsmall increments of modification, any amount of modification may in time\nbe generated. That surprise which they feel on finding one whom they\nlast saw as a boy, grown into a man, becomes incredulity when the degree\nof change is greater. Nevertheless, abundant instances are at hand of\nthe mode in which we may pass to the most diverse forms by insensible\ngradations. Arguing the matter some time since with a learned professor,\nI illustrated my position thus:--You admit that there is no apparent\nrelationship between a circle and an hyperbola. The one is a finite\ncurve; the other is an infinite one. All parts of the one are alike; of\nthe other no parts are alike [save parts on its opposite sides]. The one\nincloses a space; the other will not inclose a space though produced for\never. Yet opposite as are these curves in all their properties, they may\nbe connected together by a series of intermediate curves, no one of\nwhich differs from the adjacent ones in any appreciable degree. Thus, if\na cone be cut by a plane at right angles to its axis we get a circle.\nIf, instead of being perfectly at right angles, the plane subtends with\nthe axis an angle of 89 deg. 59', we have an ellipse which no human eye,\neven when aided by an accurate pair of compasses, can distinguish from a\ncircle. Decreasing the angle minute by minute, the ellipse becomes first\nperceptibly eccentric, then manifestly so, and by and by acquires so\nimmensely elongated a form, as to bear no recognizable resemblance to a\ncircle. By continuing this process, the ellipse passes insensibly into a\nparabola; and, ultimately, by still further diminishing the angle, into\nan hyperbola. Now here we have four different species of curve--circle,\nellipse, parabola, and hyperbola--each having its peculiar properties\nand its separate equation, and the first and last of which are quite\nopposite in nature, connected together as members of one series, all\nproducible by a single process of insensible modification.\n\nBut the blindness of those who think it absurd to suppose that complex\norganic forms may have arisen by successive modifications out of simple\nones, becomes astonishing when we remember that complex organic forms\nare daily being thus produced. A tree differs from a seed immeasurably\nin every respect--in bulk, in structure, in colour, in form, in chemical\ncomposition: differs so greatly that no visible resemblance of any kind\ncan be pointed out between them. Yet is the one changed in the course of\na few years into the other: changed so gradually, that at no moment can\nit be said--Now the seed ceases to be, and the tree exists. What can be\nmore widely contrasted than a newly-born child and the small,\nsemi-transparent spherule constituting the human ovum? The infant is so\ncomplex in structure that a cyclopaedia is needed to describe its\nconstituent parts. The germinal vesicle is so simple that it may be\ndefined in a line. Nevertheless a few months suffice to develop the one\nout of the other; and that, too, by a series of modifications so small,\nthat were the embryo examined at successive minutes, even a microscope\nwould with difficulty disclose any sensible changes. That the uneducated\nand the ill-educated should think the hypothesis that all races of\nbeings, man inclusive, may in process of time have been evolved from the\nsimplest monad, a ludicrous one, is not to be wondered at. But for the\nphysiologist, who knows that every individual being _is_ so evolved--who\nknows, further, that in their earliest condition the germs of all plants\nand animals whatever are so similar, \"that there is no appreciable\ndistinction amongst them, which would enable it to be determined whether\na particular molecule is the germ of a Conferva or of an Oak, of a\nZoophyte or of a Man;\"[1]--for him to make a difficulty of the matter is\ninexcusable. Surely if a single cell may, when subjected to certain\ninfluences, become a man in the space of twenty years; there is nothing\nabsurd in the hypothesis that under certain other influences, a cell\nmay, in the course of millions of years, give origin to the human race.\n\nWe have, indeed, in the part taken by many scientific men in this\ncontroversy of \"Law _versus_ Miracle,\" a good illustration of the\ntenacious vitality of superstitions. Ask one of our leading geologists\nor physiologists whether he believes in the Mosaic account of the\ncreation, and he will take the question as next to an insult. Either he\nrejects the narrative entirely, or understands it in some vague\nnonnatural sense. Yet one part of it he unconsciously adopts; and that,\ntoo, literally. For whence has he got this notion of \"special\ncreations,\" which he thinks so reasonable, and fights for so vigorously?\nEvidently he can trace it back to no other source than this myth which\nhe repudiates. He has not a single fact in nature to cite in proof of\nit; nor is he prepared with any chain of reasoning by which it may be\nestablished. Catechize him, and he will be forced to confess that the\nnotion was put into his mind in childhood as part of a story which he\nnow thinks absurd. And why, after rejecting all the rest of the story,\nhe should strenuously defend this last remnant of it, as though he had\nreceived it on valid authority, he would be puzzled to say.\n\nFOOTNOTE:\n\n[Footnote 1: Carpenter, _Principles of Comparative Physiology_, p. 474.]\n\n\n\n\nPROGRESS: ITS LAW AND CAUSE.\n\n    [_First published in_ The Westminster Review _for April,_ 1857.\n    _Though the ideas and illustrations contained in this essay were\n    eventually incorporated in_ First Principles, _yet I think it well\n    here to reproduce it as exhibiting the form under which the General\n    Doctrine of Evolution made its first appearance._]\n\n\nThe current conception of progress is shifting and indefinite. Sometimes\nit comprehends little more than simple growth--as of a nation in the\nnumber of its members and the extent of territory over which it spreads.\nSometimes it has reference to quantity of material products--as when the\nadvance of agriculture and manufactures is the topic. Sometimes the\nsuperior quality of these products is contemplated; and sometimes the\nnew or improved appliances by which they are produced. When, again, we\nspeak of moral or intellectual progress, we refer to states of the\nindividual or people exhibiting it; while, when the progress of Science,\nor Art, is commented upon, we have in view certain abstract results of\nhuman thought and action. Not only, however, is the current conception\nof progress more or less vague, but it is in great measure erroneous. It\ntakes in not so much the reality of progress as its accompaniments--not\nso much the substance as the shadow. That progress in intelligence seen\nduring the growth of the child into the man, or the savage into the\nphilosopher, is commonly regarded as consisting in the greater number\nof facts known and laws understood; whereas the actual progress consists\nin those internal modifications of which this larger knowledge is the\nexpression. Social progress is supposed to consist in the making of a\ngreater quantity and variety of the articles required for satisfying\nmen's wants; in the increasing security of person and property; in\nwidening freedom of action; whereas, rightly understood, social progress\nconsists in those changes of structure in the social organism which have\nentailed these consequences. The current conception is a teleological\none. The phenomena are contemplated solely as bearing on human\nhappiness. Only those changes are held to constitute progress which\ndirectly or indirectly tend to heighten human happiness; and they are\nthought to constitute progress simply _because_ they tend to heighten\nhuman happiness. But rightly to understand progress, we must learn the\nnature of these changes, considered apart from our interests. Ceasing,\nfor example, to regard the successive geological modifications that have\ntaken place in the Earth, as modifications that have gradually fitted it\nfor the habitation of Man, and as _therefore_ constituting geological\nprogress, we must ascertain the character common to these\nmodifications--the law to which they all conform. And similarly in every\nother case. Leaving out of sight concomitants and beneficial\nconsequences, let us ask what progress is in itself.\n\nIn respect to that progress which individual organisms display in the\ncourse of their evolution, this question has been answered by the\nGermans. The investigations of Wolff, Goethe, and von Baer, have\nestablished the truth that the series of changes gone through during the\ndevelopment of a seed into a tree, or an ovum into an animal, constitute\nan advance from homogeneity of structure to heterogeneity of structure.\nIn its primary stage, every germ consists of a substance that is uniform\nthroughout, both in texture and chemical composition. The first step is\nthe appearance of a difference between two parts of this substance; or,\nas the phenomenon is called in physiological language, a\ndifferentiation. Each of these differentiated divisions presently begins\nitself to exhibit some contrast of parts: and by and by these secondary\ndifferentiations become as definite as the original one. This process is\ncontinuously repeated--is simultaneously going on in all parts of the\ngrowing embryo; and by endless such differentiations there is finally\nproduced that complex combination of tissues and organs constituting the\nadult animal or plant. This is the history of all organisms whatever. It\nis settled beyond dispute that organic progress consists in a change\nfrom the homogeneous to the heterogeneous.\n\nNow, we propose in the first place to show, that this law of organic\nprogress is the law of all progress. Whether it be in the development of\nthe Earth, in the development of Life upon its surface, in the\ndevelopment of Society, of Government, of Manufactures, of Commerce, of\nLanguage, Literature, Science, Art, this same evolution of the simple\ninto the complex, through successive differentiations, holds throughout.\nFrom the earliest traceable cosmical changes down to the latest results\nof civilization, we shall find that the transformation of the\nhomogeneous into the heterogeneous, is that in which progress\nessentially consists.\n\nWith the view of showing that _if_ the Nebular Hypothesis be true, the\ngenesis of the solar system supplies one illustration of this law, let\nus assume that the matter of which the sun and planets consist was once\nin a diffused form; and that from the gravitation of its atoms there\nresulted a gradual concentration. By the hypothesis, the solar system in\nits nascent state existed as an indefinitely extended and nearly\nhomogeneous medium--a medium almost homogeneous in density, in\ntemperature, and in other physical attributes. The first change in the\ndirection of increased aggregation, brought a contrast in density and a\ncontrast in temperature, between the interior and the exterior of this\nmass. Simultaneously the drawing in of outer parts caused motions ending\nin rotation round a centre with various angular velocities. These\ndifferentiations increased in number and degree until there was evolved\nthe organized group of sun, planets, and satellites, which we now\nknow--a group which presents numerous contrasts of structure and action\namong its members. There are the immense contrasts between the sun and\nthe planets, in bulk and in weight; as well as the subordinate contrasts\nbetween one planet and another, and between the planets and their\nsatellites. There is the similarly-marked contrast between the sun as\nalmost stationary (relatively to the other members of the Solar System),\nand the planets as moving round him with great velocity: while there are\nthe secondary contrasts between the velocities and periods of the\nseveral planets, and between their simple revolutions and the double\nones of their satellites, which have to move round their primaries while\nmoving round the sun. There is the yet further strong contrast between\nthe sun and the planets in respect of temperature; and there is good\nreason to suppose that the planets and satellites differ from each other\nin their proper heats, as well as in the amounts of heat they receive\nfrom the sun. When we bear in mind that, in addition to these various\ncontrasts, the planets and satellites also differ in respect to their\ndistances from each other and their primary; in respect to the\ninclinations of their orbits, the inclinations of their axes, their\ntimes of rotation on their axes, their specific gravities, and their\nphysical constitutions; we see what a high degree of heterogeneity the\nsolar system exhibits, when compared with the almost complete\nhomogeneity of the nebulous mass out of which it is supposed to have\noriginated.\n\nPassing from this hypothetical illustration, which must be taken for\nwhat it is worth, without prejudice to the general argument, let us\ndescend to a more certain order of evidence. It is now generally agreed\namong geologists and physicists that the Earth was at one time a mass\nof molten matter. If so, it was at that time relatively homogeneous in\nconsistence, and, in virtue of the circulation which takes place in\nheated fluids, must have been comparatively homogeneous in temperature;\nand it must have been surrounded by an atmosphere consisting partly of\nthe elements of air and water, and partly of those various other\nelements which are among the more ready to assume gaseous forms at high\ntemperatures. That slow cooling by radiation which is still going on at\nan inappreciable rate, and which, though originally far more rapid than\nnow, necessarily required an immense time to produce any decided change,\nmust ultimately have resulted in the solidification of the portion most\nable to part with its heat--namely, the surface. In the thin crust thus\nformed we have the first marked differentiation. A still further\ncooling, a consequent thickening of this crust, and an accompanying\ndeposition of all solidifiable elements contained in the atmosphere,\nmust finally have been followed by the condensation of the water\npreviously existing as vapour. A second marked differentiation must thus\nhave arisen; and as the condensation must have taken place on the\ncoolest parts of the surface--namely, about the poles--there must thus\nhave resulted the first geographical distinction of parts. To these\nillustrations of growing heterogeneity, which, though deduced from known\nphysical laws, may be regarded as more or less hypothetical, Geology\nadds an extensive series that have been inductively established.\nInvestigations show that the Earth has been continually becoming more\nheterogeneous in virtue of the multiplication of sedimentary strata\nwhich form its crust; also, that it has been becoming more heterogeneous\nin respect of the composition of these strata, the later of which, being\nmade from the detritus of the earlier, are many of them rendered highly\ncomplex by the mixture of materials they contain; and further, that this\nheterogeneity has been vastly increased by the actions of the Earth's\nstill molten nucleus upon its envelope, whence have resulted not only\nmany kinds of igneous rocks, but the tilting up of sedimentary strata at\nall angles, the formation of faults and metallic veins, the production\nof endless dislocations and irregularities. Yet again, geologists teach\nus that the Earth's surface has been growing more varied in\nelevation--that the most ancient mountain systems are the smallest, and\nthe Andes and Himalayas the most modern; while in all probability there\nhave been corresponding changes in the bed of the ocean. As a\nconsequence of these ceaseless differentiations, we now find that no\nconsiderable portion of the Earth's exposed surface is like any other\nportion, either in contour, in geologic structure, or in chemical\ncomposition; and that in most parts it changes from mile to mile in all\nthese characters. Moreover, there has been simultaneously going on a\ndifferentiation of climates. As fast as the Earth cooled and its crust\nsolidified, there arose appreciable differences in temperature between\nthose parts of its surface more exposed to the sun and those less\nexposed. As the cooling progressed, these differences became more\npronounced; until there finally resulted those marked contrasts between\nregions of perpetual ice and snow, regions where winter and summer\nalternately reign for periods varying according to the latitude, and\nregions where summer follows summer with scarcely an appreciable\nvariation. At the same time the many and varied elevations and\nsubsidences of portions of the Earth's crust, bringing about the present\nirregular distribution of land and sea, have entailed modifications of\nclimate beyond those dependent on latitude; while a yet further series\nof such modifications have been produced by increasing differences of\nelevation in the land, which have in sundry places brought arctic,\ntemperate, and tropical climates to within a few miles of one another.\nAnd the general outcome of these changes is, that not only has every\nextensive region its own meteorologic conditions, but that every\nlocality in each region differs more or less from others in those\nconditions; as in its structure, its contour, its soil. Thus, between\nour existing Earth, the phenomena of whose crust neither geographers,\ngeologists, mineralogists, nor meteorologists have yet enumerated, and\nthe molten globe out of which it was evolved, the contrast in\nheterogeneity is extreme.\n\nWhen from the Earth itself we turn to the plants and animals which have\nlived, or still live, upon its surface, we find ourselves in some\ndifficulty from lack of facts. That every existing organism has been\ndeveloped out of the simple into the complex, is indeed the first\nestablished truth of all; and that every organism which existed in past\ntimes was similarly developed, is an inference no physiologist will\nhesitate to draw. But when we pass from individual forms of life to Life\nin general, and inquire whether the same law is seen in the _ensemble_\nof its manifestations,--whether modern plants and animals are of more\nheterogeneous structure than ancient ones, and whether the Earth's\npresent Flora and Fauna are more heterogeneous than the Flora and Fauna\nof the past,--we find the evidence so fragmentary, that every conclusion\nis open to dispute. Three-fifths of the Earth's surface being covered by\nwater; a great part of the exposed land being inaccessible to, or\nuntravelled by, the geologist; the greater part of the remainder having\nbeen scarcely more than glanced at; and even the most familiar portions,\nas England, having been so imperfectly explored that a new series of\nstrata has been added within these four years,--it is impossible for us\nto say with certainty what creatures have, and what have not, existed at\nany particular period. Considering the perishable nature of many of the\nlower organic forms, the metamorphosis of numerous sedimentary strata,\nand the great gaps occurring among the rest, we shall see further reason\nfor distrusting our deductions. On the one hand, the repeated discovery\nof vertebrate remains in strata previously supposed to contain none,--of\nreptiles where only fish were thought to exist,--of mammals where it was\nbelieved there were no creatures higher than reptiles,--renders it daily\nmore manifest how small is the value of negative evidence. On the other\nhand, the worthlessness of the assumption that we have discovered the\nearliest, or anything like the earliest, organic remains, is becoming\nequally clear. That the oldest known sedimentary rocks have been greatly\nchanged by igneous action, and that still older ones have been totally\ntransformed by it, is becoming undeniable. And the fact that sedimentary\nstrata earlier than any we know, have been melted up, being admitted, it\nmust also be admitted that we cannot say how far back in time this\ndestruction of sedimentary strata has been going on. Thus the title\n_Palaeozoic_, as applied to the earliest known fossiliferous strata,\ninvolves a _petitio principii_; and, for aught we know to the contrary,\nonly the last few chapters of the Earth's biological history may have\ncome down to us. On neither side, therefore, is the evidence conclusive.\nNevertheless we cannot but think that, scanty as they are, the facts,\ntaken altogether, tend to show both that the more heterogeneous\norganisms have been evolved in the later geologic periods, and that Life\nin general has been more heterogeneously manifested as time has\nadvanced. Let us cite, in illustration, the one case of the\n_Vertebrata_. The earliest known vertebrate remains are those of Fishes;\nand Fishes are the most homogeneous of the vertebrata. Later and more\nheterogeneous are Reptiles. Later still, and more heterogeneous still,\nare Birds and Mammals. If it be said that the Palaeozoic deposits, not\nbeing estuary deposits, are not likely to contain the remains of\nterrestrial vertebrata, which may nevertheless have existed at that era,\nwe reply that we are merely pointing to the leading facts, _such as they\nare_. But to avoid any such criticism, let us take the mammalian\nsubdivision only. The earliest known remains of mammals are those of\nsmall marsupials, which are the lowest of the mammalian type; while,\nconversely, the highest of the mammalian type--Man--is the most recent.\nThe evidence that the vertebrate fauna, as a whole, has become more\nheterogeneous, is considerably stronger. To the argument that the\nvertebrate fauna of the Palaeozoic period, consisting, so far as we know,\nentirely of Fishes, was less heterogeneous than the modern vertebrate\nfauna, which includes Reptiles, Birds, and Mammals, of multitudinous\ngenera, it may be replied, as before, that estuary deposits of the\nPalaeozoic period, could we find them, might contain other orders of\nvertebrata. But no such reply can be made to the argument that whereas\nthe marine vertebrata of the Palaeozoic period consisted entirely of\ncartilaginous fishes, the marine vertebrata of later periods include\nnumerous genera of osseous fishes; and that, therefore, the later marine\nvertebrate faunas are more heterogeneous than the oldest known one. Nor,\nagain, can any such reply be made to the fact that there are far more\nnumerous orders and genera of mammalian remains in the tertiary\nformations than in the secondary formations. Did we wish merely to make\nout the best case, we might dwell upon the opinion of Dr. Carpenter, who\nsays that \"the general facts of Palaeontology appear to sanction the\nbelief, that _the same plan_ may be traced out in what may be called\n_the general life of the globe_, as in _the individual life_ of every\none of the forms of organized being which now people it.\" Or we might\nquote, as decisive, the judgment of Professor Owen, who holds that the\nearlier examples of each group of creatures severally departed less\nwidely from archetypal generality than the later examples--were\nseverally less unlike the fundamental form common to the group as a\nwhole; and thus constituted a less heterogeneous group of creatures. But\nin deference to an authority for whom we have the highest respect, who\nconsiders that the evidence at present obtained does not justify a\nverdict either way, we are content to leave the question open.[2]\n\nWhether an advance from the homogeneous to the heterogeneous is or is\nnot displayed in the biological history of the globe, it is clearly\nenough displayed in the progress of the latest and most heterogeneous\ncreature--Man. It is true alike that, during the period in which the\nEarth has been peopled, the human organism has grown more heterogeneous\namong the civilized divisions of the species; and that the species, as a\nwhole, has been growing more heterogeneous in virtue of the\nmultiplication of races and the differentiation of these races from each\nother. In proof of the first of these positions, we may cite the fact\nthat, in the relative development of the limbs, the civilized man\ndeparts more widely from the general type of the placental mammalia than\ndo the lower human races. While often possessing well-developed body and\narms, the Australian has very small legs: thus reminding us of the\nchimpanzee and the gorilla, which present no great contrasts in size\nbetween the hind and fore limbs. But in the European, the greater length\nand massiveness of the legs have become marked--the fore and hind limbs\nare more heterogeneous. Again, the greater ratio which the cranial bones\nbear to the facial bones illustrates the same truth. Among the\nvertebrata in general, progress is marked by an increasing heterogeneity\nin the vertebral column, and more especially in the segments\nconstituting the skull: the higher forms being distinguished by the\nrelatively larger size of the bones which cover the brain, and the\nrelatively  smaller size of those which form the jaws, &c. Now this\ncharacteristic, which is stronger in Man than in any other creature, is\nstronger in the European than in the savage. Moreover, judging from the\ngreater extent and variety of faculty he exhibits, we may infer that the\ncivilized man has also a more complex or heterogeneous nervous system\nthan the uncivilized man: and, indeed, the fact is in part visible in\nthe increased ratio which his cerebrum bears to the subjacent ganglia,\nas well as in the wider departure from symmetry in its convolutions. If\nfurther elucidation be needed, we may find it in every nursery. The\ninfant European has sundry marked points of resemblance to the lower\nhuman races; as in the flatness of the alae of the nose, the depression\nof its bridge, the divergence and forward opening of the nostrils, the\nform of the lips, the absence of a frontal sinus, the width between the\neyes, the smallness of the legs. Now, as the developmental process by\nwhich these traits are turned into those of the adult European, is a\ncontinuation of that change from the homogeneous to the heterogeneous\ndisplayed during the previous evolution of the embryo, which every\nanatomist will admit; it follows that the parallel developmental process\nby which the like traits of the barbarous races have been turned into\nthose of the civilized races, has also been a continuation of the change\nfrom the homogeneous to the heterogeneous. The truth of the second\nposition--that Mankind, as a whole, have become more heterogeneous--is\nso obvious as scarcely to need illustration. Every work on Ethnology, by\nits divisions and subdivisions of races, bears testimony to it. Even\nwere we to admit the hypothesis that Mankind originated from several\nseparate stocks, it would still remain true, that as, from each of these\nstocks, there have sprung many now widely-different tribes, which are\nproved by philological evidence to have had a common origin, the race as\na whole is far less homogeneous than it once was. Add to which, that we\nhave, in the Anglo-Americans, an example of a new variety arising\nwithin these few generations; and that, if we may trust to the\ndescriptions of observers, we are likely soon to have another such\nexample in Australia.\n\nOn passing from Humanity under its individual form, to Humanity as\nsocially embodied, we find the general law still more variously\nexemplified. The change from the homogeneous to the heterogeneous is\ndisplayed in the progress of civilization as a whole, as well as in the\nprogress of every nation; and is still going on with increasing\nrapidity. As we see in existing barbarous tribes, society in its first\nand lowest form is a homogeneous aggregation of individuals having like\npowers and like functions: the only marked difference of function being\nthat which accompanies difference of sex. Every man is warrior, hunter,\nfisherman, tool-maker, builder; every woman performs the same\ndrudgeries. Very early, however, in the course of social evolution,\nthere arises an incipient differentiation between the governing and the\ngoverned. Some kind of chieftainship seems coeval with the first advance\nfrom the state of separate wandering families to that of a nomadic\ntribe. The authority of the strongest or the most cunning makes itself\nfelt among a body of savages as in a herd of animals, or a posse of\nschoolboys. At first, however, it is indefinite, uncertain; is shared by\nothers of scarcely inferior power; and is unaccompanied by any\ndifference in occupation or style of living: the first ruler kills his\nown game, makes his own weapons, builds his own hut, and, economically\nconsidered, does not differ from others of his tribe. Gradually, as the\ntribe progresses, the contrast between the governing and the governed\ngrows more decided. Supreme power becomes hereditary in one family; the\nhead of that family, ceasing to provide for his own wants, is served by\nothers; and he begins to assume the sole office of ruling. At the same\ntime there has been arising a co-ordinate species of government--that\nof Religion. As all ancient records and traditions prove, the earliest\nrulers are regarded as divine personages. The maxims and commands they\nuttered during their lives are held sacred after their deaths, and are\nenforced by their divinely-descended successors; who in their turns are\npromoted to the pantheon of the race, here to be worshipped and\npropitiated along with their predecessors: the most ancient of whom is\nthe supreme god, and the rest subordinate gods. For a long time these\nconnate forms of government--civil and religious--remain closely\nassociated. For many generations the king continues to be the chief\npriest, and the priesthood to be members of the royal race. For many\nages religious law continues to include more or less of civil\nregulation, and civil law to possess more or less of religious sanction;\nand even among the most advanced nations these two controlling agencies\nare by no means completely separated from each other. Having a common\nroot with these, and gradually diverging from them, we find yet another\ncontrolling agency--that of Ceremonial usages. All titles of honour are\noriginally the names of the god-king; afterwards of the god and the\nking; still later of persons of high rank; and finally come, some of\nthem, to be used between man and man. All forms of complimentary address\nwere at first the expressions of submission from prisoners to their\nconqueror, or from subjects to their ruler, either human or\ndivine--expressions which were afterwards used to propitiate subordinate\nauthorities, and slowly descended into ordinary intercourse. All modes\nof salutation were once obeisances made before the monarch and used in\nworship of him after his death. Presently others of the god-descended\nrace were similarly saluted; and by degrees some of the salutations\nhave become the due of all.[3] Thus, no sooner does the\noriginally-homogeneous social mass differentiate  into the governed and\nthe governing parts, than this last exhibits an incipient\ndifferentiation into religious and secular--Church and State; while at\nthe same time there begins to be differentiated from both, that less\ndefinite species of government which rules our daily intercourse--a\nspecies of government which, as we may see in heralds' colleges, in\nbooks of the peerage, in masters of ceremonies, is not without a certain\nembodiment of its own. Each of these is itself subject to successive\ndifferentiations. In the course of ages, there arises, as among\nourselves, a highly complex political organization of monarch,\nministers, lords and commons, with their subordinate administrative\ndepartments, courts of justice, revenue offices, &c., supplemented in\nthe provinces by municipal governments, county governments, parish or\nunion governments--all of them more or less elaborated. By its side\nthere grows up a highly complex religious organization, with its various\ngrades of officials, from archbishops down to sextons, its colleges,\nconvocations, ecclesiastical courts, &c.; to all which must be added the\never-multiplying independent sects, each with its general and local\nauthorities. And at the same time there is developed a highly complex\naggregation of customs, manners, and temporary fashions, enforced by\nsociety at large, and serving to control those minor transactions\nbetween man and man which are not regulated by civil and religious law.\nMoreover, it is to be observed that this increasing heterogeneity in the\ngovernmental appliances of each nation, has been accompanied by an\nincreasing heterogeneity in the assemblage of governmental appliances of\ndifferent nations: all nations being more or less unlike in their\npolitical systems and legislation, in their creeds and religious\ninstitutions, in their customs and ceremonial usages.\n\nSimultaneously there has been going on a second differentiation of a\nmore familiar kind; that, namely, by which the mass of the community has\nbeen segregated into distinct classes and orders of workers. While the\ngoverning part has undergone the complex development above detailed, the\ngoverned part has undergone an equally complex development, which has\nresulted in that minute division of labour characterizing advanced\nnations. It is needless to trace out this progress from its first\nstages, up through the caste-divisions of the East and the incorporated\nguilds of Europe, to the elaborate producing and distributing\norganization existing among ourselves. It has been an evolution which,\nbeginning with a tribe whose members severally perform the same actions\neach for himself, ends with a civilized community whose members\nseverally perform different actions for each other; and an evolution\nwhich has transformed the solitary producer of any one commodity into a\ncombination of producers who, united under a master, take separate parts\nin the manufacture of such commodity. But there are yet other and higher\nphases of this advance from the homogeneous to the heterogeneous in the\nindustrial organization of society. Long after considerable progress has\nbeen made in the division of labour among different classes of workers,\nthere is still little or no division of labour among the widely\nseparated parts of the community: the nation continues comparatively\nhomogeneous in the respect that in each district the same occupations\nare pursued. But when roads and other means of transit become numerous\nand good, the different districts begin to assume different functions,\nand to become mutually dependent. The calico manufacture locates itself\nin this county, the woollen-cloth manufacture in that; silks are\nproduced here, lace there; stockings in one place, shoes in another;\npottery, hardware, cutlery, come to have their special towns; and\nultimately every locality becomes more or less distinguished from the\nrest by the leading occupation carried on in it. This subdivision of\nfunctions shows itself not only among the different parts of the same\nnation, but among different nations. That exchange of commodities which\nfree-trade is increasing so largely, will ultimately have the effect of\nspecializing, in a greater or less degree, the industry of each people.\nSo that, beginning with a barbarous tribe, almost if not quite\nhomogeneous in the functions of its members, the progress has been, and\nstill is, towards an economic aggregation of the whole human race;\ngrowing ever more heterogeneous in respect of the separate functions\nassumed by separate nations, the separate functions assumed by the local\nsections of each nation, the separate functions assumed by the many\nkinds of makers and traders in each town, and the separate functions\nassumed by the workers united in producing each commodity.\n\nThe law thus clearly exemplified in the evolution of the social\norganism, is exemplified with equal clearness in the evolution of all\nproducts of human thought and action; whether concrete or abstract, real\nor ideal. Let us take Language as our first illustration.\n\nThe lowest form of language is the exclamation, by which an entire idea\nis vaguely conveyed through a single sound, as among the lower animals.\nThat human language ever consisted solely of exclamations, and so was\nstrictly homogeneous in respect of its parts of speech, we have no\nevidence. But that language can be traced down to a form in which nouns\nand verbs are its only elements, is an established fact. In the gradual\nmultiplication of parts of speech out of these primary ones--in the\ndifferentiation of verbs into active and passive, of nouns into abstract\nand concrete--in the rise of distinctions of mood, tense, person, of\nnumber and case--in the formation of auxiliary verbs, of adjectives,\nadverbs, pronouns, prepositions, articles--in the divergence of those\norders, genera, species, and varieties of parts of speech by which\ncivilized races express minute modifications of meaning--we see a change\nfrom the homogeneous to the heterogeneous. Another aspect under which we\nmay trace the development of language is the divergence of words having\ncommon origins. Philology early disclosed the truth that in all\nlanguages words may be grouped into families, the members of each of\nwhich are allied by their derivation. Names springing from a primitive\nroot, themselves become the parents of other names still further\nmodified. And by the aid of those systematic modes which presently\narise, of making derivatives and forming compound terms, there is\nfinally developed a tribe of words so heterogeneous in sound and\nmeaning, that to the uninitiated it seems incredible they should be\nnearly related. Meanwhile from other roots there are being evolved other\nsuch tribes, until there results a language of some sixty thousand or\nmore unlike words, signifying as many unlike objects, qualities, acts.\nYet another way in which language in general advances from the\nhomogeneous to the heterogeneous, is in the multiplication of languages.\nWhether all languages have grown from one stock, or whether, as some\nphilologists think, they have grown from two or more stocks, it is clear\nthat since large groups of languages, as the Indo-European, are of one\nparentage, they have become distinct through a process of continuous\ndivergence. The same diffusion over the Earth's surface which has led to\ndifferentiations of race, has simultaneously led to differentiations of\nspeech: a truth which we see further illustrated in each nation by the\ndistinct dialects found in separate districts. Thus the progress of\nLanguage conforms to the general law, alike in the evolution of\nlanguages, in the evolution of families of words, and in the evolution\nof parts of speech.\n\nOn passing from spoken to written language, we come upon several classes\nof facts, having similar implications. Written language is connate with\nPainting and Sculpture; and at first all three are appendages of\nArchitecture, and have a direct connection with the primary form of all\nGovernment--the theocratic. Merely noting by the way the fact that\nsundry wild races, as for example the Australians and the tribes of\nSouth Africa, are given to depicting personages and events upon the\nwalls of caves, which are probably regarded as sacred places, let us\npass to the case of the Egyptians. Among them, as also among the\nAssyrians, we find mural paintings used to decorate the temple of the\ngod and the palace of the king (which were, indeed, originally\nidentical); and as such they were governmental appliances in the same\nsense as state-pageants and religious feasts were. They were\ngovernmental appliances in another way: representing as they did the\nworship of the god, the triumphs of the god-king, the submission of his\nsubjects, and the punishment of the rebellious. Further, they were\ngovernmental, as being the products of an art reverenced by the people\nas a sacred mystery. From the habitual use of this pictorial\nrepresentation there grew up the but-slightly-modified practice of\npicture-writing--a practice which was found still extant among North\nAmerican peoples at the time they were discovered. By abbreviations\nanalogous to those still going on in our own written language, the most\nfrequently-recurring of these pictured figures were successively\nsimplified; and ultimately there grew up a system of symbols, most of\nwhich had but distant resemblances to the things for which they stood.\nThe inference that the hieroglyphics of the Egyptians were thus\nproduced, is confirmed by the fact that the picture-writing of the\nMexicans was found to have given birth to a like family of ideographic\nforms; and among them, as among the Egyptians, these had been partially\ndifferentiated into the _kuriological_ or imitative, and the _tropical_\nor symbolic; which were, however, used together in the same record. In\nEgypt, written language underwent a further differentiation, whence\nresulted the _hieratic_ and the _epistolographic_ or _enchorial_; both\nof which are derived from the original hieroglyphic. At the same time we\nfind that for the expression of proper names, which could not be\notherwise conveyed, signs having phonetic values were employed; and\nthough it is alleged that the Egyptians never achieved complete\nalphabetic writing, yet it can scarcely be doubted that these phonetic\nsymbols, occasionally used in aid of their ideographic ones, were the\ngerms of an alphabetic system. Once having become separate from\nhieroglyphics, alphabetic writing itself underwent numerous\ndifferentiations--multiplied alphabets were produced; between most of\nwhich, however, more or less connection can still be traced. And in each\ncivilized nation there has now grown up, for the representation of one\nset of sounds, several sets of written signs used for distinct purposes.\nFinally, from writing diverged printing; which, uniform in kind as it\nwas at first, has since become multiform.\n\nWhile written language was passing through its first stages of\ndevelopment, the mural decoration which contained its root was being\ndifferentiated into Painting and Sculpture. The gods, kings, men, and\nanimals represented, were originally marked by indented outlines and\ncoloured. In most cases these outlines were of such depth, and the\nobject they circumscribed so far rounded and marked out in its leading\nparts, as to form a species of work intermediate between intaglio and\nbas-relief. In other cases we see an advance upon this: the raised\nspaces between the figures being chiselled off, and the figures\nthemselves appropriately tinted, a painted bas-relief was produced. The\nrestored Assyrian architecture at Sydenham exhibits this style of art\ncarried to greater perfection--the persons and things represented,\nthough still barbarously coloured, are carved out with more truth and in\ngreater detail: and in the winged lions and bulls used for the angles of\ngateways, we may see a considerable advance towards a completely\nsculptured figure; which, nevertheless, is still coloured, and still\nforms part of the building. But while in Assyria the production of a\nstatue proper seems to have been little, if at all, attempted, we may\ntrace in Egyptian art the gradual separation of the sculptured figure\nfrom the wall. A walk through the collection in the British Museum\nshows this; while at the same time it affords an opportunity of\nobserving the traces which the independent statues bear of their\nderivation from bas-relief: seeing that nearly all of them not only\ndisplay that fusion of the legs with one another and of the arms with\nthe body which is characteristic of bas-relief, but have the back united\nfrom head to foot with a block which stands in place of the original\nwall. Greece repeated the leading stages of this progress. On the\nfriezes of Greek Temples, were coloured bas-reliefs representing\nsacrifices, battles, processions, games--all in some sort religious. The\npediments contained painted sculptures more or less united with the\ntympanum, and having for subjects the triumphs of gods or heroes. Even\nstatues definitely separated from buildings were coloured; and only in\nthe later periods of Greek civilization does the differentiation of\nSculpture from Painting appear to have become complete. In Christian art\nwe may trace a parallel re-genesis. All early works of art throughout\nEurope were religious in subject--represented Christs, crucifixions,\nvirgins, holy families, apostles, saints. They formed integral parts of\nchurch architecture, and were among the means of exciting worship; as in\nRoman Catholic countries they still are. Moreover, the sculptured\nfigures of Christ on the cross, of virgins, of saints, were coloured;\nand it needs but to call to mind the painted madonnas still abundant in\ncontinental churches and highways, to perceive the significant fact that\nPainting and Sculpture continue in closest connection with each other\nwhere they continue in closest connection with their parent. Even when\nChristian sculpture became differentiated from painting, it was still\nreligious and governmental in its subjects--was used for tombs in\nchurches and statues of kings; while, at the same time, painting, where\nnot purely ecclesiastical, was applied to the decoration of palaces, and\nbesides representing royal personages, was mostly devoted to sacred\nlegends. Only in recent times have painting and sculpture become quite\nseparate and mainly secular. Only within these few centuries has\nPainting been divided into historical, landscape, marine, architectural,\ngenre, animal, still-life, &c.; and Sculpture grown heterogeneous in\nrespect of the variety of real and ideal subjects with which it occupies\nitself.\n\nStrange as it seems then, we find that all forms of written language, of\nPainting, and of Sculpture, have a common root in the politico-religious\ndecorations of ancient temples and palaces. Little resemblance as they\nnow have, the landscape that hangs against the wall, and the copy of the\n_Times_ lying on the table, are remotely akin. The brazen face of the\nknocker which the postman has just lifted, is related not only to the\nwoodcuts of the _Illustrated London News_ which he is delivering, but to\nthe characters of the _billet-doux_ which accompanies it. Between the\npainted window, the prayer-book on which its light falls, and the\nadjacent monument, there is consanguinity. The effigies on our coins,\nthe signs over shops, the coat of arms outside the carriage panel, and\nthe placards inside the omnibus, are, in common with dolls and\npaper-hangings, lineally descended from the rude sculpture-paintings in\nwhich ancient peoples represented the triumphs and worship of their\ngod-kings. Perhaps no example can be given which more vividly\nillustrates the multiplicity and heterogeneity of the products that in\ncourse of time may arise by successive differentiations from a common\nstock.\n\nBefore passing to other classes of facts, it should be observed that the\nevolution of the homogeneous into the heterogeneous is displayed not\nonly in the separation of Painting and Sculpture from Architecture and\nfrom each other, and in the greater variety of subjects they embody, but\nit is further shown in the structure of each work. A modern picture or\nstatue is of far more heterogeneous nature than an ancient one. An\nEgyptian sculpture-fresco usually represents all its figures as at the\nsame distance from the eye; and so is less heterogeneous than a\npainting that represents them as at various distances from the eye. It\nexhibits all objects as exposed to the same degree of light; and so is\nless heterogeneous than a painting which exhibits its different objects\nand different parts of each object as in different degrees of light. It\nuses chiefly the primary colours, and these in their full intensities;\nand so is less heterogeneous than a painting which, introducing the\nprimary colours but sparingly, employs numerous intermediate tints, each\nof heterogeneous composition, and differing from the rest not only in\nquality but in strength. Moreover, we see in these early works great\nuniformity of conception. The same arrangement of figures is perpetually\nreproduced--the same actions, attitudes, faces, dresses. In Egypt the\nmodes of representation were so fixed that it was sacrilege to introduce\na novelty. The Assyrian bas-reliefs display parallel characters.\nDeities, kings, attendants, winged-figures and animals, are time after\ntime depicted in like positions, holding like implements, doing like\nthings, and with like expression or non-expression of face. If a\npalm-grove is introduced, all the trees are of the same height, have the\nsame number of leaves, and are equidistant. When water is imitated, each\nwave is a counterpart of the rest; and the fish, almost always of one\nkind, are evenly distributed over the surface. The beards of the kings,\nthe gods, and the winged-figures, are everywhere similar; as are the\nmanes of the lions, and equally so those of the horses. Hair is\nrepresented throughout by one form of curl. The king's beard is quite\narchitecturally built up of compound tiers of uniform curls, alternating\nwith twisted tiers placed in a transverse direction, and arranged with\nperfect regularity; and the terminal tufts of the bulls' tails are\nrepresented in exactly the same manner. Without tracing out analogous\nfacts in early Christian art, in which, though less striking, they are\nstill visible, the advance in heterogeneity will be sufficiently\nmanifest on remembering that in the pictures of our own day the\ncomposition is endlessly varied; the attitudes, faces, expressions,\nunlike; the subordinate objects different in sizes, forms, textures; and\nmore or less of contrast even in the smallest details. Or, if we compare\nan Egyptian statue, seated bolt upright on a block, with hands on knees,\nfingers parallel, eyes looking straight forward, and the two sides\nperfectly symmetrical in every particular, with a statue of the advanced\nGreek school or the modern school, which is asymmetrical in respect of\nthe attitude of the head, the body, the limbs, the arrangement of the\nhair, dress, appendages, and in its relations to neighbouring objects,\nwe shall see the change from the homogeneous to the heterogeneous\nclearly manifested.\n\nIn the co-ordinate origin and gradual differentiation of Poetry, Music,\nand Dancing, we have another series of illustrations. Rhythm in words,\nrhythm in sounds, and rhythm in motions, were in the beginning parts of\nthe same thing, and have only in process of time become separate things.\nAmong existing barbarous tribes we find them still united. The dances of\nsavages are accompanied by some kind of monotonous chant, the clapping\nof hands, the striking of rude instruments: there are measured\nmovements, measured words, and measured tones. The early records of\nhistoric races similarly show these three forms of metrical action\nunited in religious festivals. In the Hebrew writings we read that the\ntriumphal ode composed by Moses on the defeat of the Egyptians, was sung\nto an accompaniment of dancing and timbrels. The Israelites danced and\nsung \"at the inauguration of the golden calf. And as it is generally\nagreed that this representation of the Deity was borrowed from the\nmysteries of Apis, it is probable that the dancing was copied from that\nof the Egyptians on those occasions.\" Again, in Greece the like relation\nis everywhere seen: the original type being there, as probably in other\ncases, a simultaneous chanting and mimetic representation of the life\nand adventures of the hero or the god. The Spartan dances were\naccompanied by hymns and songs; and in general the Greeks had \"no\nfestivals or religious assemblies but what were accompanied with songs\nand dances\"--both of them being forms of worship used before altars.\nAmong the Romans, too, there were sacred dances: the Salian and\nLupercalian being named as of that kind. And even in Christian\ncountries, as at Limoges, in comparatively recent times, the people have\ndanced in the choir in honour of a saint. The incipient separation of\nthese once-united arts from each other and from religion, was early\nvisible in Greece. Probably diverging from dances partly religious,\npartly warlike, as the Corybantian, came the war-dances proper, of which\nthere were various kinds. Meanwhile Music and Poetry, though still\nunited, came to have an existence separate from Dancing. The primitive\nGreek poems, religious in subject, were not recited but chanted; and\nthough at first the chant of the poet was accompanied by the dance of\nthe chorus, it ultimately grew into independence. Later still, when the\npoem had been differentiated into epic and lyric--when it became the\ncustom to sing the lyric and recite the epic--poetry proper was born. As\nduring the same period musical instruments were being multiplied, we may\npresume that music came to have an existence apart from words. And both\nof them were beginning to assume other forms besides the religious.\nFacts having like implications might be cited from the histories of\nlater times and peoples; as the practices of our own early minstrels,\nwho sang to the harp heroic narratives versified by themselves to music\nof their own composition: thus uniting the now separate offices of poet,\ncomposer, vocalist, and instrumentalist. But, without further\nillustration, the common origin and gradual differentiation of Dancing,\nPoetry, and Music will be sufficiently manifest.\n\nThe advance from the homogeneous to the heterogeneous is displayed not\nonly in the separation of these arts from each other and from religion,\nbut also in the multiplied differentiations which each of them\nafterwards undergoes. Not to dwell upon the numberless kinds of dancing\nthat have, in course of time, come into use: and not to occupy space in\ndetailing the progress of poetry, as seen in the development of the\nvarious forms of metre, of rhyme, and of general organization; let us\nconfine our attention to music as a type of the group. As implied by the\ncustoms of still extant barbarous races, the first musical instruments\nwere, without doubt, percussive--sticks, calabashes, tom-toms--and were\nused simply to mark the time of the dance; and in this constant\nrepetition of the same sound, we see music in its most homogeneous form.\nThe Egyptians had a lyre with three strings. The early lyre of the\nGreeks had four, constituting their tetrachord. In course of some\ncenturies lyres of seven and eight strings were employed; and, by the\nexpiration of a thousand years, they had advanced to their \"great\nsystem\" of the double octave. Through all which changes there of course\narose a greater heterogeneity of melody. Simultaneously there came into\nuse the different modes--Dorian, Ionian, Phrygian, AEolian, and\nLydian--answering to our keys; and of these there were ultimately\nfifteen. As yet, however, there was but little heterogeneity in the time\nof their music. Instrumental music being at first merely the\naccompaniment of vocal music, and vocal music being subordinated to\nwords,--the singer being also the poet, chanting his own compositions\nand making the lengths of his notes agree with the feet of his\nverses,--there resulted a tiresome uniformity of measure, which, as Dr.\nBurney says, \"no resources of melody could disguise.\" Lacking the\ncomplex rhythm obtained by our equal bars and unequal notes, the only\nrhythm was that produced by the quantity of the syllables, and was of\nnecessity comparatively monotonous. And further, it maybe observed that\nthe chant thus resulting, being like recitative, was much less clearly\ndifferentiated from ordinary speech than is our modern song.\nNevertheless, in virtue of the extended range of notes in use, the\nvariety of modes, the occasional variations of time consequent on\nchanges of metre, and the multiplication of instruments, music had,\ntowards the close of Greek civilization, attained to considerable\nheterogeneity--not indeed as compared with our music, but as compared\nwith that which preceded it. Still, there existed nothing but melody:\nharmony was unknown. It was not until Christian church-music had reached\nsome development, that music in parts was evolved; and then it came into\nexistence through a very unobtrusive differentiation. Difficult as it\nmay be to conceive _a priori_ how the advance from melody to harmony\ncould take place without a sudden leap, it is none the less true that it\ndid so. The circumstance which prepared the way for it was the\nemployment of two choirs singing alternately the same air. Afterwards it\nbecame the practice--very possibly first suggested by a mistake--for the\nsecond choir to commence before the first had ceased; thus producing a\nfugue. With the simple airs then in use, a partially-harmonious fugue\nmight not improbably thus result: and a very partially-harmonious fugue\nsatisfied the ears of that age, as we know from still preserved\nexamples. The idea having once been given, the composing of airs\nproductive of fugal harmony would naturally grow up, as in some way it\n_did_ grow up, out of this alternate choir-singing. And from the fugue\nto concerted music of two, three, four, and more parts, the transition\nwas easy. Without pointing out in detail the increasing complexity that\nresulted from introducing notes of various lengths, from the\nmultiplication of keys, from the use of accidentals, from varieties of\ntime, and so forth, it needs but to contrast music as it is, with music\nas it was, to see how immense is the increase of heterogeneity. We see\nthis if, looking at music in its _ensemble_, we enumerate its many\ndifferent genera and species--if we consider the divisions into vocal,\ninstrumental, and mixed; and their subdivisions into music for\ndifferent voices and different instruments--if we observe the many forms\nof sacred music, from the simple hymn, the chant, the canon, motet,\nanthem, &c., up to the oratorio; and the still more numerous forms of\nsecular music, from the ballad up to the serenata, from the instrumental\nsolo up to the symphony. Again, the same truth is seen on comparing any\none sample of aboriginal music with a sample of modern music--even an\nordinary song for the piano; which we find to be relatively very\nheterogeneous, not only in respect of the variety in the pitches and in\nthe lengths of the notes, the number of different notes sounding at the\nsame instant in company with the voice, and the variations of strength\nwith which they are sounded and sung, but in respect of the changes of\nkey, the changes of time, the changes of _timbre_ of the voice, and the\nmany other modifications of expression. While between the old monotonous\ndance-chant and a grand opera of our own day, with its endless\norchestral complexities and vocal combinations, the contrast in\nheterogeneity is so extreme that it seems scarcely credible that the one\nshould have been the ancestor of the other.\n\nWere they needed, many further illustrations might be cited. Going back\nto the early time when the deeds of the god-king were recorded in\npicture-writings on the walls of temples and palaces, and so constituted\na rude literature, we might trace the development of Literature through\nphases in which, as in the Hebrew Scriptures, it presents in one work\ntheology, cosmogony, history, biography, law, ethics, poetry; down to\nits present heterogeneous development, in which its separated divisions\nand subdivisions are so numerous and varied as to defy complete\nclassification. Or we might trace out the evolution of Science;\nbeginning with the era in which it was not yet differentiated from Art,\nand was, in union with Art, the handmaid of Religion; passing through\nthe era in which the sciences were so few and rudimentary, as to be\nsimultaneously cultivated by the same men; and ending with the era in\nwhich the genera and species are so numerous that few can enumerate\nthem, and no one can adequately grasp even one genus. Or we might do the\nlike with Architecture, with the Drama, with Dress. But doubtless the\nreader is already weary of illustrations; and our promise has been amply\nfulfilled. Abundant proof has been given that the law of organic\ndevelopment formulated by von Baer, is the law of all development. The\nadvance from the simple to the complex, through a process of successive\ndifferentiations, is seen alike in the earliest changes of the Universe\nto which we can reason our way back, and in the earliest changes which\nwe can inductively establish; it is seen in the geologic and climatic\nevolution of the Earth; it is seen in the unfolding of every single\norganism on its surface, and in the multiplication of kinds of\norganisms; it is seen in the evolution of Humanity, whether contemplated\nin the civilized individual, or in the aggregate of races; it is seen in\nthe evolution of Society in respect alike of its political, its\nreligious, and its economical organization; and it is seen in the\nevolution of all those endless concrete and abstract products of human\nactivity which constitute the environment of our daily life. From the\nremotest past which Science can fathom, up to the novelties of\nyesterday, that in which progress essentially consists, is the\ntransformation of the homogeneous into the heterogeneous.\n\n       *       *       *       *       *\n\nAnd now, must not this uniformity of procedure be a consequence of some\nfundamental necessity? May we not rationally seek for some all-pervading\nprinciple which determines this all-pervading process of things? Does\nnot the universality of the _law_ imply a universal _cause_?\n\nThat we can comprehend such cause, noumenally considered, is not to be\nsupposed. To do this would be to solve that ultimate mystery which must\never transcend human intelligence. But it still may be possible for us\nto reduce the law of all progress, above set forth, from the condition\nof an empirical generalization, to the condition of a rational\ngeneralization. Just as it was possible to interpret Kepler's laws as\nnecessary consequences of the law of gravitation; so it may be possible\nto interpret this law of progress, in its multiform manifestations, as\nthe necessary consequence of some similarly universal principle. As\ngravitation was assignable as the _cause_ of each of the groups of\nphenomena which Kepler generalized; so may some equally simple attribute\nof things be assignable as the cause of each of the groups of phenomena\ngeneralized in the foregoing pages. We may be able to affiliate all\nthese varied evolutions of the homogeneous into the heterogeneous, upon\ncertain facts of immediate experience, which, in virtue of endless\nrepetition, we regard as necessary.\n\nThe probability of a common cause, and the possibility of formulating\nit, being granted, it will be well, first, to ask what must be the\ngeneral characteristics of such cause, and in what direction we ought to\nlook for it. We can with certainty predict that it has a high degree of\nabstractness; seeing that it is common to such infinitely-varied\nphenomena. We need not expect to see in it an obvious solution of this\nor that form of progress; because it is equally concerned with forms of\nprogress bearing little apparent resemblance to them: its association\nwith multiform orders of facts, involves its dissociation from any\nparticular order of facts. Being that which determines progress of every\nkind--astronomic, geologic, organic, ethnologic, social, economic,\nartistic, &c.--it must be involved with some fundamental trait displayed\nin common by these; and must be expressible in terms of this fundamental\ntrait. The only obvious respect in which all kinds of progress are\nalike, is, that they are modes of _change_; and hence, in some\ncharacteristic of changes in general, the desired solution will probably\nbe found. We may suspect _a priori_ that in some universal law of change\nlies the explanation of this universal transformation of the\nhomogeneous into the heterogeneous.\n\nThus much premised, we pass at once to the statement of the law, which\nis this:--_Every active force produces more than one change--every cause\nproduces more than one effect._\n\nTo make this proposition comprehensible, a few examples must be given.\nWhen one body strikes another, that which we usually regard as the\neffect, is a change of position or motion in one or both bodies. But a\nmoment's thought shows us that this is a very incomplete view of the\nmatter. Besides the visible mechanical result, sound is produced; or, to\nspeak accurately, a vibration in one or both bodies, which is\ncommunicated to the surrounding air; and under some circumstances we\ncall this the effect. Moreover, the air has not only been made to\nundulate, but has had currents caused in it by the transit of the\nbodies. Further, there is a disarrangement of the particles of the two\nbodies in the neighbourhood of their point of collision; amounting, in\nsome cases, to a visible condensation. Yet more, this condensation is\naccompanied by the disengagement of heat. In some cases a spark--that\nis, light--results, from the incandescence of a portion struck off; and\nsometimes this incandescence is associated with chemical combination.\nThus, by the mechanical force expended in the collision, at least five,\nand often more, different kinds of changes have been produced. Take,\nagain, the lighting of a candle. Primarily this is a chemical change\nconsequent on a rise of temperature. The process of combination having\nonce been started by extraneous heat, there is a continued formation of\ncarbonic acid, water, &c.--in itself a result more complex than the\nextraneous heat that first caused it. But accompanying this process of\ncombination there is a production of heat; there is a production of\nlight; there is an ascending column of hot gases generated; there are\ninflowing currents set going in the surrounding air. Moreover, the\ncomplicating of effects does not end here: each of the several changes\nproduced becomes the parent of further changes. The carbonic acid given\noff will by and by combine with some base; or under the influence of\nsunshine give up its carbon to the leaf of a plant. The water will\nmodify the hygrometric state of the air around; or, if the current of\nhot gases containing it comes against a cold body, will be condensed:\naltering the temperature of the surface it covers. The heat given out\nmelts the subjacent tallow, and expands whatever it warms. The light,\nfalling on various substances, calls forth from them reactions by which\nits composition is modified; and so divers colours are produced.\nSimilarly even with these secondary actions, which may be traced out\ninto ever-multiplying ramifications, until they become too minute to be\nappreciated. And thus it is with all changes whatever. No case can be\nnamed in which an active force does not evolve forces of several kinds,\nand each of these, other groups of forces. Universally the effect is\nmore complex than the cause.\n\nDoubtless the reader already foresees the course of our argument. This\nmultiplication of effects, which is displayed in every event of to-day,\nhas been going on from the beginning; and is true of the grandest\nphenomena of the universe as of the most insignificant. From the law\nthat every active force produces more than one change, it is an\ninevitable corollary that during the past there has been an ever-growing\ncomplication of things. Throughout creation there must have gone on, and\nmust still go on, a never-ceasing transformation of the homogeneous into\nthe heterogeneous. Let us trace this truth in detail.\n\nWithout committing ourselves to it as more than a speculation, though a\nhighly probable one, let us again commence with the evolution of the\nSolar System out of a nebulous medium. The hypothesis is that from the\nmutual attraction of the molecules of a diffused mass whose form is\nunsymmetrical, there results not only condensation but rotation. While\nthe condensation and the rate of rotation go on increasing, the\napproach of the molecules is necessarily accompanied by an increasing\ntemperature. As the temperature rises, light begins to be evolved; and\nultimately there results a revolving sphere of fluid matter radiating\nintense heat and light--a sun. There are reasons for believing that, in\nconsequence of the higher tangential velocity originally possessed by\nthe outer parts of the condensing nebulous mass, there will be\noccasional detachments of rotating rings; and that, from the breaking up\nof these nebulous rings, there will arise masses which in the course of\ntheir condensation repeat the actions of the parent mass, and so produce\nplanets and their satellites--an inference strongly supported by the\nstill extant rings of Saturn. Should it hereafter be satisfactorily\nshown that planets and satellites were thus generated, a striking\nillustration will be afforded of the highly heterogeneous effects\nproduced by the primary homogeneous cause; but it will serve our present\npurpose to point to the fact that from the mutual attraction of the\nparticles of an irregular nebulous mass there result condensation,\nrotation, heat, and light.\n\nIt follows as a corollary from the Nebular Hypothesis, that the Earth\nmust once have been incandescent; and whether the Nebular Hypothesis be\ntrue or not, this original incandescence of the Earth is now inductively\nestablished--or, if not established, at least rendered so highly\nprobable that it is an accepted geological doctrine. Let us look first\nat the astronomical attributes of this once molten globe. From its\nrotation there result the oblateness of its form, the alternations of\nday and night, and (under the influence of the moon and in a smaller\ndegree the sun) the tides, aqueous and atmospheric. From the inclination\nof its axis, there result the many differences of the seasons, both\nsimultaneous and successive, that pervade its surface, and from the same\ncause joined with the action of the moon on the equatorial protuberance\nthere results the precession of the equinoxes. Thus the multiplication\nof effects is obvious. Several of the differentiations due to the\ngradual cooling of the Earth have been already noticed--as the formation\nof a crust, the solidification of sublimed elements, the precipitation\nof water, &c.,--and we here again refer to them merely to point out that\nthey are simultaneous effects of the one cause, diminishing heat. Let us\nnow, however, observe the multiplied changes afterwards arising from the\ncontinuance of this one cause. The cooling of the Earth involves its\ncontraction. Hence the solid crust first formed is presently too large\nfor the shrinking nucleus; and as it cannot support itself, inevitably\nfollows the nucleus. But a spheroidal envelope cannot sink down into\ncontact with a smaller internal spheroid, without disruption: it must\nrun into wrinkles as the rind of an apple does when the bulk of its\ninterior decreases from evaporation. As the cooling progresses and the\nenvelope thickens, the ridges consequent on these contractions will\nbecome greater, rising ultimately into hills and mountains; and the\nlater systems of mountains thus produced will not only be higher, as we\nfind them to be, but will be longer, as we also find them to be. Thus,\nleaving out of view other modifying forces, we see what immense\nheterogeneity of surface has arisen from the one cause, loss of heat--a\nheterogeneity which the telescope shows us to be paralleled on the face\nof Mars, and which in the moon too, where aqueous and atmospheric\nagencies have been absent, it reveals under a somewhat different form.\nBut we have yet to notice another kind of heterogeneity of surface\nsimilarly and simultaneously caused. While the Earth's crust was still\nthin, the ridges produced by its contraction must not only have been\nsmall, but the spaces between these ridges must have rested with great\nevenness upon the subjacent liquid spheroid; and the water in those\narctic and antarctic regions in which it first condensed, must have been\nevenly distributed. But as fast as the crust thickened and gained\ncorresponding strength, the lines of fracture from time to time caused\nin it, must have occurred at greater distances apart; the intermediate\nsurfaces must have followed the contracting nucleus with less\nuniformity; and there must have resulted larger areas of land and water.\nIf any one, after wrapping up an orange in tissue paper, and observing\nnot only how small are the wrinkles, but how evenly the intervening\nspaces lie upon the surface of the orange, will then wrap it up in thick\ncartridge-paper, and note both the greater height of the ridges and the\nlarger spaces throughout which the paper does not touch the orange, he\nwill realize the fact that, as the Earth's solid envelope grew thicker,\nthe areas of elevation and depression increased. In place of islands\nhomogeneously dispersed amid an all-embracing sea, there must have\ngradually arisen heterogeneous arrangements of continent and ocean. Once\nmore, this double change in the extent and in the elevation of the\nlands, involved yet another species of heterogeneity--that of\ncoast-line. A tolerably even surface raised out of the ocean must have a\nsimple, regular sea-margin; but a surface varied by table-lands and\nintersected by mountain-chains must, when raised out of the ocean, have\nan outline extremely irregular both in its leading features and in its\ndetails. Thus, multitudinous geological and geographical results are\nslowly brought about by this one cause--the contraction of the Earth.\n\nWhen we pass from the agency termed igneous, to aqueous and atmospheric\nagencies, we see the like ever-growing complications of effects. The\ndenuding actions of air and water, joined with those of changing\ntemperature, have, from the beginning, been modifying every exposed\nsurface. Oxidation, heat, wind, frost, rain, glaciers, rivers, tides,\nwaves, have been unceasingly producing disintegration; varying in kind\nand amount according to local circumstances. Acting upon a tract of\ngranite, they here work scarcely an appreciable effect; there cause\nexfoliations of the surface, and a resulting heap of _debris_ and\nboulders; and elsewhere, after decomposing the feldspar into a white\nclay, carry away this and the accompanying quartz and mica, and deposit\nthem in separate beds, fluviatile and marine. When the exposed land\nconsists of several unlike kinds of sedimentary strata, or igneous\nrocks, or both, denudation produces changes proportionably more\nheterogeneous. The formations being disintegrable in different degrees,\nthere follows an increased irregularity of surface. The areas drained by\ndifferent rivers being differently constituted, these rivers carry down\nto the sea different combinations of ingredients; and so sundry new\nstrata of unlike compositions are formed. And here we may see very\nsimply illustrated, the truth, which we shall presently have to trace\nout in more involved cases, that in proportion to the heterogeneity of\nthe object or objects on which any force expends itself, is the\nheterogeneity of the effects. A continent of complex structure, exposing\nmany strata irregularly distributed, raised to various levels, tilted up\nat all angles, will, under the same denuding agencies, give origin to\ninnumerable and involved results: each district must be differently\nmodified; each river must carry down a different kind of detritus; each\ndeposit must be differently distributed by the entangled currents, tidal\nand other, which wash the contorted shores; and this multiplication of\nresults must manifestly be greatest where the complexity of surface is\ngreatest.\n\nHere we might show how the general truth, that every active force\nproduces more than one change, is again exemplified in the\nhighly-involved flow of the tides, in the ocean currents, in the winds,\nin the distribution of rain, in the distribution of heat, and so forth.\nBut not to dwell upon these, let us, for the fuller elucidation of this\ntruth in relation to the inorganic world, consider what would be the\nconsequences of some extensive cosmical catastrophe--say the subsidence\nof Central America. The immediate results of the disturbance would\nthemselves be sufficiently complex. Besides the numberless dislocations\nof strata, the ejections of igneous matter, the propagation of\nearthquake vibrations thousands of miles around, the loud explosions,\nand the escape of gases; there would be the rush of the Atlantic and\nPacific Oceans to fill the vacant space, the subsequent recoil of\nenormous waves, which would traverse both these oceans and produce\nmyriads of changes along their shores, the corresponding atmospheric\nwaves complicated by the currents surrounding each volcanic vent, and\nthe electrical discharges with which such disturbances are accompanied.\nBut these temporary effects would be insignificant compared with the\npermanent ones. The currents of the Atlantic and Pacific would be\naltered in their directions and amounts. The distribution of heat\nachieved by those ocean currents would be different from what it is. The\narrangement of the isothermal lines, not only on neighbouring\ncontinents, but even throughout Europe, would be changed. The tides\nwould flow differently from what they do now. There would be more or\nless modification of the winds in their periods, strengths, directions,\nqualities. Rain would fall scarcely anywhere at the same times and in\nthe same quantities as at present. In short, the meteorological\nconditions thousands of miles off, on all sides, would be more or less\nrevolutionized. Thus, without taking into account the infinitude of\nmodifications which these changes would produce upon the flora and\nfauna, both of land and sea, the reader will perceive the immense\nheterogeneity of the results wrought out by one force, when that force\nexpends itself upon a previously complicated area; and he will draw the\ncorollary that from the beginning the complication has advanced at an\nincreasing rate.\n\nBefore going on to show how organic progress also depends on the law\nthat every force produces more than one change, we have to notice the\nmanifestation of this law in yet another species of inorganic\nprogress--namely, chemical. The same general causes that have wrought\nout the heterogeneity of the Earth, physically considered, have\nsimultaneously wrought out its chemical heterogeneity. There is every\nreason to believe that at an extreme heat the elements cannot combine.\nEven under such heat as can be artificially produced, some very strong\naffinities yield, as, for instance, that of oxygen for hydrogen; and the\ngreat majority of chemical compounds are decomposed at much lower\ntemperatures. But without insisting on the highly probable inference,\nthat when the Earth was in its first state of incandescence there were\nno chemical combinations at all, it will suffice for our purpose to\npoint to the unquestionable fact that the compounds which can exist at\nthe highest temperatures, and which must, therefore, have been the first\nthat were formed as the Earth cooled, are those of the simplest\nconstitutions. The protoxides--including under that head the alkalies,\nearths, &c.--are, as a class, the most stable compounds we know: most of\nthem resisting decomposition by any heat we can generate. These are\ncombinations of the simplest order--are but one degree less homogeneous\nthan the elements themselves. More heterogeneous, less stable, and\ntherefore later in the Earth's history, are the deutoxides, tritoxides,\nperoxides, &c.; in which two, three, four, or more atoms of oxygen are\nunited with one atom of metal or other element. Higher than these in\nheterogeneity are the hydrates; in which an oxide of hydrogen, united\nwith an oxide of some other element, forms a substance whose atoms\nseverally contain at least four ultimate atoms of three different kinds.\nYet more heterogeneous and less stable still are the salts; which\npresent us with molecules each made up of five, six, seven, eight, ten,\ntwelve, or more atoms, of three, if not more, kinds. Then there are the\nhydrated salts, of a yet greater heterogeneity, which undergo partial\ndecomposition at much lower temperatures. After them come the further\ncomplicated supersalts and double salts, having a stability again\ndecreased; and so throughout. Without entering into qualifications for\nwhich space fails, we believe no chemist will deny it to be a general\nlaw of these inorganic combinations that, _other things equal_, the\nstability decreases as the complexity increases. When we pass to the\ncompounds of organic chemistry, we find this general law still further\nexemplified: we find much greater complexity and much less stability. A\nmolecule of albumen, for instance, consists of 482 ultimate atoms of\nfive different kinds. Fibrine, still more intricate in constitution,\ncontains in each molecule, 298 atoms of carbon, 49 of nitrogen, 2 of\nsulphur, 228 of hydrogen, and 92 of oxygen--in all, 669 atoms; or, more\nstrictly speaking, equivalents. And these two substances are so unstable\nas to decompose at quite ordinary temperatures; as that to which the\noutside of a joint of roast meat is exposed. Thus it is manifest that\nthe present chemical heterogeneity of the Earth's surface has arisen by\ndegrees, as the decrease of heat has permitted; and that it has shown\nitself in three forms--first, in the multiplication of chemical\ncompounds; second, in the greater number of different elements contained\nin the more modern of these compounds; and third, in the higher and more\nvaried multiples in which these more numerous elements combine.\n\nTo say that this advance in chemical heterogeneity is due to the one\ncause, diminution of the Earth's temperature, would be to say too much;\nfor it is clear that aqueous and atmospheric agencies have been\nconcerned; and further, that the affinities of the elements themselves\nare implied. The cause has all along been a composite one: the cooling\nof the Earth having been simply the most general of the concurrent\ncauses, or assemblage of conditions. And here, indeed, it may be\nremarked that in the several classes of facts already dealt with\n(excepting, perhaps, the first), and still more in those with which we\nshall presently deal, the causes are more or less compound; as indeed\nare nearly all causes with which we are acquainted. Scarcely any\nchange can rightly be ascribed to one agency alone, to the neglect of\nthe permanent or temporary conditions under which only this agency\nproduces the change. But as it does not materially affect our argument,\nwe prefer, for simplicity's sake, to use throughout the popular mode of\nexpression. Perhaps it will be further objected, that to assign loss of\nheat as the cause of any changes, is to attribute these changes not to a\nforce, but to the absence of a force. And this is true. Strictly\nspeaking, the changes should be attributed to those forces which come\ninto action when the antagonist force is withdrawn. But though there is\ninaccuracy in saying that the freezing of water is due to the loss of\nits heat, no practical error arises from it; nor will a parallel laxity\nof expression vitiate our statements respecting the multiplication of\neffects. Indeed, the objection serves but to draw attention to the fact,\nthat not only does the exertion of a force produce more than one change,\nbut the withdrawal of a force produces more than one change.\n\nReturning to the thread of our exposition, we have next to trace,\nthroughout organic progress, this same all-pervading principle. And\nhere, where the evolution of the homogeneous into the heterogeneous was\nfirst observed, the production of many effects by one cause is least\neasy to demonstrate. The development of a seed into a plant, or an ovum\ninto an animal, is so gradual, while the forces which determine it are\nso involved, and at the same time so unobtrusive, that it is difficult\nto detect the multiplication of effects which is elsewhere so obvious.\nBut, guided by indirect evidence, we may safely conclude that here too\nthe law holds. Note, first, how numerous are the changes which any\nmarked action works upon an adult organism--a human being, for instance.\nAn alarming sound or sight, besides the impressions on the organs of\nsense and the nerves, may produce a start, a scream, a distortion of\nthe face, a trembling consequent on general muscular relaxation, a burst\nof perspiration, a rush of blood to the brain, followed possibly by\narrest of the heart's action and by syncope; and if the subject be\nfeeble, an indisposition with its long train of complicated symptoms may\nset in. Similarly in cases of disease. A minute portion of the small-pox\nvirus introduced into the system, will, in a severe case, cause, during\nthe first stage, rigors, heat of skin, accelerated pulse, furred tongue,\nloss of appetite, thirst, epigastric uneasiness, vomiting, headache,\npains in the back and limbs, muscular weakness, convulsions, delirium,\n&c.; in the second stage, cutaneous eruption, itching, tingling, sore\nthroat, swelled fauces, salivation, cough, hoarseness, dyspnoea, &c.;\nand in the third stage, oedematous inflammations, pneumonia, pleurisy,\ndiarrhoea, inflammation of the brain, ophthalmia, erysipelas, &c.:\neach of which enumerated symptoms is itself more or less complex.\nMedicines, special foods, better air, might in like manner be instanced\nas producing multipled results. Now it needs only to consider that the\nmany changes thus wrought by one force upon an adult organism, will be\nin part paralleled in an embryo organism, to understand how here also,\nthe evolution of the homogeneous into the heterogeneous may be due to\nthe production of many effects by one cause. The external heat, which,\nfalling on a matter having special proclivities, determines the first\ncomplications of the germ, may, by acting on these, superinduce further\ncomplications; upon these still higher and more numerous ones; and so on\ncontinually: each organ as it is developed serving, by its actions and\nreactions on the rest, to initiate new complexities. The first\npulsations of the foetal heart must simultaneously aid the unfolding\nof every part. The growth of each tissue, by taking from the blood\nspecial proportions of elements, must modify the constitution of the\nblood; and so must modify the nutrition of all the other tissues. The\nheart's action, implying as it does a certain waste, necessitates an\naddition to the blood of effete matters, which must influence the rest\nof the system, and perhaps, as some think, cause the formation of\nexcretory organs. The nervous connexions established among the viscera\nmust further multiply their mutual influences; and so continually. Still\nstronger becomes the probability of this view when we call to mind the\nfact, that the same germ may be evolved into different forms according\nto circumstances. Thus, during its earlier stages, every embryo is\nsexless--becomes either male or female as the balance of forces acting\non it determines. Again, it is a well-established fact that the larva of\na working-bee will develop into a queen-bee, if before it is too late,\nits food be changed to that on which the larvae of queen-bees are fed.\nAll which instances suggest that the proximate cause of each advance in\nembryonic complication is the action of incident forces upon the\ncomplication previously existing. Indeed, we may find _a priori_ reason\nto think that the evolution proceeds after this manner. For since no\ngerm, animal or vegetal, contains the slightest rudiment or indication\nof the future organism--since the microscope has shown us that the first\nprocess set up in every fertilized germ, is a process of repeated\nspontaneous fissions ending in the production of a mass of cells, not\none of which exhibits any special character; there seems no alternative\nbut to suppose that the partial organization at any moment existing in a\ngrowing embryo, is transformed by the agencies acting upon it into the\nsucceeding phase of organization, and this into the next, until, through\never-increasing complexities, the ultimate form is reached. Not indeed\nthat we can thus really explain the production of any plant or animal.\nWe are still in the dark respecting those mysterious properties in\nvirtue of which the germ, when subject to fit influences, undergoes the\nspecial changes that begin the series of transformations. All we aim to\nshow, is, that given a germ possessing those particular proclivities\ndistinguishing the species to which it belongs, and the evolution of an\norganism from it, probably depends on that multiplication of effects\nwhich we have seen to be the cause of progress in general, so far as we\nhave yet traced it.\n\nWhen, leaving the development of single plants and animals, we pass to\nthat of the Earth's flora and fauna, the course of our argument again\nbecomes clear and simple. Though, as was admitted in the first part of\nthis article, the fragmentary facts Paleontology has accumulated, do not\nclearly warrant us in saying that, in the lapse of geologic time, there\nhave been evolved more heterogeneous organisms, and more heterogeneous\nassemblages of organisms, yet we shall now see that there _must_ ever\nhave been a tendency towards these results. We shall find that the\nproduction of many effects by one cause, which as already shown, has\nbeen all along increasing the physical heterogeneity of the Earth, has\nfurther involved an increasing heterogeneity in its flora and fauna,\nindividually and collectively. An illustration will make this clear.\nSuppose that by a series of upheavals, occurring, as they are now known\nto do, at long intervals, the East Indian Archipelago were to be, step\nby step, raised into a continent, and a chain of mountains formed along\nthe axis of elevation. By the first of these upheavals, the plants and\nanimals inhabiting Borneo, Sumatra, New Guinea, and the rest, would be\nsubjected to slightly modified sets of conditions. The climate in\ngeneral would be altered in temperature, in humidity, and in its\nperiodical variations; while the local differences would be multiplied.\nThese modifications would affect, perhaps inappreciably, the entire\nflora and fauna of the region. The change of level would produce\nadditional modifications: varying in different species, and also in\ndifferent members of the same species, according to their distance from\nthe axis of elevation. Plants, growing only on the sea-shore in special\nlocalities, might become extinct. Others, living only in swamps of a\ncertain humidity, would, if they survived at all, probably undergo\nvisible changes of appearance. While still greater alterations would\noccur in the plants gradually spreading over the lands newly raised\nabove the sea. The animals and insects living on these modified plants,\nwould themselves be in some degree modified by change of food, as well\nas by change of climate; and the modification would be more marked\nwhere, from the dwindling or disappearance of one kind of plant, an\nallied kind was eaten. In the lapse of the many generations arising\nbefore the next upheaval, the sensible or insensible alterations thus\nproduced in each species would become organized--there would be a more\nor less complete adaptation to the new conditions. The next upheaval\nwould superinduce further organic changes, implying wider divergences\nfrom the primary forms; and so repeatedly. But now let it be observed\nthat the revolution thus resulting would not be a substitution of a\nthousand more or less modified species for the thousand original\nspecies; but in place of the thousand original species there would arise\nseveral thousand species, or varieties, or changed forms. Each species\nbeing distributed over an area of some extent, and tending continually\nto colonize the new area exposed, its different members would be subject\nto different sets of changes. Plants and animals spreading towards the\nequator would not be affected in the same way as others spreading from\nit. Those spreading towards the new shores would undergo changes unlike\nthe changes undergone by those spreading into the mountains. Thus, each\noriginal race of organisms, would become the root from which diverged\nseveral races differing more or less from it and from each other; and\nwhile some of these might subsequently disappear, probably more than one\nwould survive in the next geologic period: the very dispersion itself\nincreasing the chances of survival. Not only would there be certain\nmodifications thus caused by change of physical conditions and food, but\nalso in some cases other modifications caused by change of habit. The\nfauna of each island, peopling, step by step, the newly-raised tracts,\nwould eventually come in contact with the faunas of other islands; and\nsome members of these other faunas would be unlike any creatures before\nseen. Herbivores meeting with new beasts of prey, would, in some cases,\nbe led into modes of defence or escape differing from those previously\nused; and simultaneously the beasts of prey would modify their modes of\npursuit and attack. We know that when circumstances demand it, such\nchanges of habit _do_ take place in animals; and we know that if the new\nhabits become the dominant ones, they must eventually in some degree\nalter the organization. Observe now, however, a further consequence.\nThere must arise not simply a tendency towards the differentiation of\neach race of organisms into several races; but also a tendency to the\noccasional production of a somewhat higher organism. Taken in the mass\nthese divergent varieties which have been caused by fresh physical\nconditions and habits of life, will exhibit changes quite indefinite in\nkind and degree; and changes that do not necessarily constitute an\nadvance. Probably in most cases the modified type will be neither more\nnor less heterogeneous than the original one. In some cases the habits\nof life adopted being simpler than before, a less heterogeneous\nstructure will result: there will be a retrogradation. But it _must_ now\nand then occur, that some division of a species, falling into\ncircumstances which give it rather more complex experiences, and demand\nactions somewhat more involved, will have certain of its organs further\ndifferentiated in proportionately small degrees,--will become slightly\nmore heterogeneous. Thus, in the natural course of things, there will\nfrom time to time arise an increased heterogeneity both of the Earth's\nflora and fauna, and of individual races included in them. Omitting\ndetailed explanations, and allowing for the qualifications which cannot\nhere be specified, we think it is clear that geological mutations have\nall along tended to complicate the forms of life, whether regarded\nseparately or collectively. The same causes which have led to the\nevolution of the Earth's crust from the simple into the complex, have\nsimultaneously led to a parallel evolution of the Life upon its surface.\nIn this case, as in previous ones, we see that the transformation of the\nhomogeneous into the heterogeneous is consequent upon the universal\nprinciple, that every active force produces more than one change.\n\nThe deduction here drawn from the established truths of geology and the\ngeneral laws of life, gains immensely in weight on finding it to be in\nharmony with an induction drawn from direct experience. Just that\ndivergence of many races from one race, which we inferred must have been\ncontinually occurring during geologic time, we know to have occurred\nduring the pre-historic and historic periods, in man and domestic\nanimals. And just that multiplication of effects which we concluded must\nhave produced the first, we see has produced the last. Single causes, as\nfamine, pressure of population, war, have periodically led to further\ndispersions of mankind and of dependent creatures: each such dispersion\ninitiating new modifications, new varieties of type. Whether all the\nhuman races be or be not derived from one stock, philology makes it\nclear that whole groups of races now easily distinguishable from each\nother, were originally one race,--that the diffusion of one race into\ndifferent climates and conditions of existence, has produced many\nmodified forms of it. Similarly with domestic animals. Though in some\ncases--as that of dogs--community of origin will perhaps be disputed,\nyet in other cases--as that of the sheep or the cattle of our own\ncountry--it will not be questioned that local differences of climate,\nfood, and treatment, have transformed one original breed into numerous\nbreeds now become so far distinct as to produce unstable hybrids.\nMoreover, through the complication of effects flowing from single\ncauses, we here find, what we before inferred, not only an increase of\ngeneral heterogeneity, but also of special heterogeneity. While of the\ndivergent divisions and subdivisions of the human race many have\nundergone changes not constituting an advance; while in some the type\nmay have degraded; in others it has become decidedly more heterogeneous.\nThe civilized European departs more widely from the vertebrate archetype\nthan does the savage. Thus, both the law and the cause of progress,\nwhich, from lack of evidence, can be but hypothetically substantiated in\nrespect of the earlier forms of life on our globe, can be actually\nsubstantiated in respect of the latest forms.[4]\n\nIf the advance of Man towards greater heterogeneity is traceable to the\nproduction of many effects by one cause, still more clearly may the\nadvance of Society towards greater heterogeneity be so explained.\nConsider the growth of an industrial organization. When, as must\noccasionally happen, some member of a tribe displays unusual aptitude\nfor making an article of general use--a weapon, for instance--which was\nbefore made by each man for himself, there arises a tendency towards the\ndifferentiation of that member into a maker of such weapon. His\ncompanions--warriors and hunters all of them,--severally feel the\nimportance of having the best weapons that can be made; and are\ntherefore certain to offer strong inducements to this skilled individual\nto make weapons for them. He, on the other hand, having not only an\nunusual faculty, but an unusual liking, for making such weapons (the\ntalent and the desire for any occupation being commonly associated), is\npredisposed to fulfil each commission on the offer of an adequate\nreward: especially as his love of distinction is also gratified and his\nliving facilitated. This first specialization of function, once\ncommenced, tends ever to become more decided. On the side of the\nweapon-maker practice gives increased skill--increased superiority to\nhis products. On the side of his clients, cessation of practice entails\ndecreased skill. Thus the influences which determine this division of\nlabour grow stronger in both ways; and the incipient heterogeneity is,\non the average of cases, likely to become permanent for that generation\nif no longer. This process not only differentiates the social mass into\ntwo parts, the one monopolizing, or almost monopolizing, the performance\nof a certain function, and the other losing the habit, and in some\nmeasure the power, of performing that function; but it tends to initiate\nother differentiations. The advance described implies the introduction\nof barter,--the maker of weapons has, on each occasion, to be paid in\nsuch other articles as he agrees to take in exchange. He will not\nhabitually take in exchange one kind of article, but many kinds. He does\nnot want mats only, or skins, or fishing-gear, but he wants all these,\nand on each occasion will bargain for the particular things he most\nneeds. What follows? If among his fellows there exist any slight\ndifferences of skill in the manufacture of these various things, as\nthere are almost sure to do, the weapon-maker will take from each one\nthe thing which that one excels in making: he will exchange for mats\nwith him whose mats are superior, and will bargain for the\nfishing-gear of him who has the best. But he who has bartered away his\nmats or his fishing-gear, must make other mats or fishing-gear for\nhimself; and in so doing must, in some degree, further develop his\naptitude. Thus it results that the small specialities of faculty\npossessed by various members of the tribe, will tend to grow more\ndecided. And whether or not there ensue distinct differentiations of\nother individuals into makers of particular articles, it is clear that\nincipient differentiations take place throughout the tribe: the one\noriginal cause produces not only the first dual effect, but a number of\nsecondary dual effects, like in kind, but minor in degree. This process,\nof which traces may be seen among schoolboys, cannot well produce\nlasting effects in an unsettled tribe; but where there grows up a fixed\nand multiplying community, such differentiations become permanent, and\nincrease with each generation. The enhanced demand for every commodity,\nintensifies the functional activity of each specialized person or class;\nand this renders the specialization more definite where it already\nexists, and establishes it where it is but nascent. By increasing the\npressure on the means of subsistence, a larger population again augments\nthese results; seeing that each person is forced more and more to\nconfine himself to that which he can do best, and by which he can gain\nmost. Presently, under these same stimuli, new occupations arise.\nCompeting workers, ever aiming to produce improved articles,\noccasionally discover better processes or raw materials. The\nsubstitution of bronze for stone entails on him who first makes it a\ngreat increase of demand; so that he or his successor eventually finds\nall his time occupied in making the bronze for the articles he sells,\nand is obliged to depute the fashioning of these articles to others;\nand, eventually, the making of bronze, thus differentiated from a\npre-existing occupation, becomes an occupation by itself. But now mark\nthe ramified changes which follow this change. Bronze presently\nreplaces stone, not only in the articles it was first used for, but in\nmany others--in arms, tools, and utensils of various kinds: and so\naffects the manufacture of them. Further, it affects the processes which\nthese utensils subserve, and the resulting products,--modifies\nbuildings, carvings, personal decorations. Yet again, it sets going\nmanufactures which were before impossible, from lack of a material fit\nfor the requisite implements. And all these changes react on the\npeople--increase their manipulative skill, their intelligence, their\ncomfort,--refine their habits and tastes. Thus the evolution of a\nhomogeneous society into a heterogeneous one, is clearly consequent on\nthe general principle, that many effects are produced by one cause.\n\nSpace permitting, we might show how the localization oL special\nindustries in special parts of a kingdom, as well as the minute\nsubdivision of labour in the making of each commodity, are similarly\ndetermined. Or, turning to a somewhat different order of illustrations,\nwe might dwell on the multitudinous changes--material, intellectual,\nmoral,--caused by printing; or the further extensive series of changes\nwrought by gunpowder. But leaving the intermediate phases of social\ndevelopment, let us take a few illustrations from its most recent and\nits passing phases. To trace the effects of steam-power, in its manifold\napplications to mining, navigation, and manufactures of all kinds, would\ncarry us into unmanageable detail. Let us confine ourselves to the\nlatest embodiment of steam power--the locomotive engine. This, as the\nproximate cause of our railway system, has changed the face of the\ncountry, the course of trade, and the habits of the people. Consider,\nfirst, the complicated sets of changes that precede the making of every\nrailway--the provisional arrangements, the meetings, the registration,\nthe trial section, the parliamentary survey, the lithographed plans, the\nbooks of reference, the local deposits and notices, the application to\nParliament, the passing Standing Orders Committee, the first, second,\nand third readings: each of which brief heads indicates a multiplicity\nof transactions, and the extra development of sundry occupations--as\nthose of engineers, surveyors, lithographers, parliamentary agents,\nshare-brokers; and the creation of sundry others--as those of\ntraffic-takers, reference-takers. Consider, next, the yet more marked\nchanges implied in railway construction--the cuttings, embankings,\ntunnellings, diversions of roads; the building of bridges and stations,\nthe laying down of ballast, sleepers, and rails; the making of engines,\ntenders, carriages, and waggons: which processes, acting on numerous\ntrades, increase the importation of timber, the quarrying of stone, the\nmanufacture of iron, the mining of coal, the burning of bricks;\ninstitute a variety of special manufactures weekly advertised in the\n_Railway Times_; and, finally, open the way to sundry new occupations,\nas those of drivers, stokers, cleaners, plate-layers, &c., &c. And then\nconsider the changes, still more numerous and involved, which railways\nin action produce on the community at large. Business agencies are\nestablished where previously they would not have paid; goods are\nobtained from remote wholesale houses instead of near retail ones; and\ncommodities are used which distance once rendered inaccessible. Again,\nthe diminished cost of carriage tends to specialize more than ever the\nindustries of different districts--to confine each manufacture to the\nparts in which, from local advantages, it can be best carried on.\nFurther, the fall in freights, facilitating distribution, equalizes\nprices, and also, on the average, lowers prices: thus bringing divers\narticles within the means of those before unable to buy them, and so\nincreasing their comforts and improving their habits. At the same time\nthe practice of travelling is immensely extended. People who never\nbefore dreamed of it, take trips to the sea; visit their distant\nrelations; make tours; and so we are benefited in body, feelings, and\nideas. The more prompt transmission of letters and of news produces\nother marked changes--makes the pulse of the nation faster. Once more,\nthere arises a wide dissemination of cheap literature through railway\nbook-stalls, and of advertisements in railway carriages: both of them\naiding ulterior progress. And the countless changes here briefly\nindicated are consequent on the invention of the locomotive engine. The\nsocial organism has been rendered more heterogeneous in virtue of the\nmany new occupations introduced, and the many old ones further\nspecialized; prices of nearly all things in every place have been\naltered; each trader has modified his way of doing business; and every\nperson has been affected in his actions, thoughts, emotions.\n\nIllustrations to the same effect might be indefinitely accumulated, but\nthey are needless. The only further fact demanding notice, is, that we\nhere see still more clearly the truth before pointed out, that in\nproportion as the area on which any force expends itself becomes\nheterogeneous, the results are in a yet higher degree multiplied in\nnumber and kind. While among the simple tribes to whom it was first\nknown, caoutchouc caused but few changes, among ourselves the changes\nhave been so many and varied that the history of them occupies a\nvolume.[5] Upon the small, homogeneous community inhabiting one of the\nHebrides, the electric telegraph would produce, were it used, scarcely\nany results; but in England the results it produces are multitudinous.\nThe comparatively simple organization under which our ancestors lived\nfive centuries ago, could have undergone but few modifications from an\nevent like the recent one at Canton; but now, the legislative decision\nrespecting it sets up many hundreds of complex modifications, each of\nwhich will be the parent of numerous future ones.\n\nSpace permitting, we could willingly have pursued the argument in\nrelation to all the subtler results of civilization. As before we showed\nthat the law of progress to which the organic and inorganic worlds\nconform, is also conformed to by Language, the plastic arts, Music, &c.;\nso might we here show that the cause which we have hitherto found to\ndetermine progress holds in these cases also. Instances might be given\nproving how, in Science, an advance of one division presently advances\nother divisions--how Astronomy has been immensely forwarded by\ndiscoveries in Optics, while other optical discoveries have initiated\nMicroscopic Anatomy, and greatly aided the growth of Physiology--how\nChemistry has indirectly increased our knowledge of Electricity,\nMagnetism, Biology, Geology--how Electricity has reacted on Chemistry\nand Magnetism, and has developed our views of Light and Heat. In\nLiterature the same truth might be exhibited in the manifold effects of\nthe primitive mystery-play, as originating the modern drama, which has\nvariously branched; or in the still multiplying forms of periodical\nliterature which have descended from the first newspaper, and which have\nseverally acted and reacted on other forms of literature and on each\nother. The influence which a new school of Painting--as that of the\npre-Raphaelites--exercises upon other schools; the hints which all kinds\nof pictorial art are deriving from Photography; the complex results of\nnew critical doctrines, as those of Mr. Ruskin, might severally be dwelt\nupon as displaying the like multiplication of effects.\n\nBut we venture to think our case is already made out. The imperfections\nof statement which brevity has necessitated, do not, we believe,\ninvalidate the propositions laid down. The qualifications here and there\ndemanded would not, if made, affect the inferences. Though, in tracing\nthe genesis of progress, we have frequently spoken of complex causes as\nif they were simple ones; it still remains true that such causes are far\nless complex than their results. Detailed criticisms do not affect our\nmain position. Endless facts go to show that every kind of progress is\nfrom the homogeneous to the heterogeneous; and that it is so because\neach change is followed by many changes. And it is significant that\nwhere the facts are most accessible and abundant, there these truths are\nmost manifest.\n\nHowever, to avoid committing ourselves to more than is yet proved, we\nmust be content with saying that such are the law and the cause of all\nprogress that is known to us. Should the Nebular Hypothesis ever be\nestablished, then it will become manifest that the Universe at large,\nlike every organism, was once homogeneous; that as a whole, and in every\ndetail, it has unceasingly advanced towards greater heterogeneity. It\nwill be seen that as in each event of to-day, so from the beginning, the\ndecomposition of every expended force into several forces has been\nperpetually producing a higher complication; that the increase of\nheterogeneity so brought about is still going on and must continue to go\non; and that thus progress is not an accident, not a thing within human\ncontrol, but a beneficent necessity.\n\n       *       *       *       *       *\n\nA few words must be added on the ontological bearings of our argument.\nProbably not a few will conclude that here is an attempted solution of\nthe great questions with which Philosophy in all ages has perplexed\nitself. Let none thus deceive themselves. After all that has been said,\nthe ultimate mystery remains just as it was. The explanation of that\nwhich is explicable, does but bring out into greater clearness the\ninexplicableness of that which remains behind. Little as it seems to do\nso, fearless inquiry tends continually to give a firmer basis to all\ntrue Religion. The timid sectarian, obliged to abandon one by one the\nsuperstitions bequeathed to him, and daily finding his cherished beliefs\nmore and more shaken, secretly fears that all things may some day be\nexplained; and has a corresponding dread of Science: thus evincing the\nprofoundest of all infidelity--the fear lest the truth be bad. On the\nother hand, the sincere man of science, content to follow wherever the\nevidence leads him, becomes by each new inquiry more profoundly\nconvinced that the Universe is an insoluble problem. Alike in the\nexternal and the internal worlds, he sees himself in the midst of\nceaseless changes, of which he can discover neither beginning nor end.\nIf, tracing back the evolution of things, he allows himself to entertain\nthe hypothesis that all matter once existed in a diffused form, he finds\nit impossible to conceive how this came to be so; and equally, if he\nspeculates on the future, he can assign no limit to the grand succession\nof phenomena ever unfolding themselves before him. Similarly, if he\nlooks inward, he perceives that both terminations of the thread of\nconsciousness are beyond his grasp: he cannot remember when or how\nconsciousness commenced, and he cannot examine the consciousness at any\nmoment existing; for only a state of consciousness which is already past\ncan become the object of thought, and never one which is passing. When,\nagain, he turns from the succession of phenomena, external or internal,\nto their essential nature, he is equally at fault. Though he may succeed\nin resolving all properties of objects into manifestations of force, he\nis not thereby enabled to conceive what force is; but finds, on the\ncontrary, that the more he thinks about it, the more he is baffled.\nSimilarly, though analysis of mental actions may finally bring him down\nto sensations as the original materials out of which all thought is\nwoven, he is none the forwarder; for he cannot in the least comprehend\nsensation. Inward and outward things he thus discovers to be alike\ninscrutable in their ultimate genesis and nature. He sees that the\nMaterialist and Spiritualist controversy is a mere war of words; the\ndisputants being equally absurd--each believing he understands that\nwhich it is impossible for any man to understand. In all directions his\ninvestigations eventually bring him face to face with the unknowable;\nand he ever more clearly perceives it to be the unknowable. He learns at\nonce the greatness and the littleness of human intellect--its power in\ndealing with all that comes within the range of experience; its\nimpotence in dealing with all that transcends experience. He feels more\nvividly than any others can feel, the utter incomprehensibleness of the\nsimplest fact, considered in itself. He alone truly _sees_ that absolute\nknowledge is impossible. He alone _knows_ that under all things there\nlies an impenetrable mystery.\n\nFOOTNOTES:\n\n[Footnote 2: Since this was written (in 1857) the advance of\npaleontological discovery, especially in America, has shown\nconclusively, in respect of certain groups of vertebrates, that higher\ntypes have arisen by modifications of lower; so that, in common with\nothers, Prof. Huxley, to whom the above allusion is made, now admits, or\nrather asserts, biological progression, and, by implication, that there\nhave arisen more heterogeneous organic forms and a more heterogeneous\nassemblage of organic forms.]\n\n[Footnote 3: For detailed proof of these assertions see essay on\n\"Manners and Fashion.\"]\n\n[Footnote 4: The argument concerning organic evolution contained in this\nparagraph and the one preceding it, stands verbatim as it did when first\npublished in the _Westminster Review_ for April, 1857. I have thus left\nit without the alteration of a word that it may show the view I then\nheld concerning the origin of species. The sole cause recognized is that\nof direct adaptation of constitution to conditions consequent on\ninheritance of the modifications of structure resulting from use and\ndisuse. There is no recognition of that further cause disclosed in Mr.\nDarwin's work, published two and a half years later--the indirect\nadaptation resulting from the natural selection of favourable\nvariations. The multiplication of effects is, however, equally\nillustrated in whatever way the adaptation to changing conditions is\neffected, or if it is effected in both ways, as I hold. I may add that\nthere is indicated the view that the succession of organic forms is not\nserial but proceeds by perpetual divergence and re-divergence--that\nthere has been a continual \"divergence of many races from one race\":\neach species being a \"root\" from which several other species branch out;\nand the growth of a tree being thus the implied symbol.]\n\n[Footnote 5: \"Personal Narrative of the Origin of the Caoutchouc, or\nIndia-Rubber Manufacture in England.\" By Thomas Hancock.]\n\n\n\n\nTRANSCENDENTAL PHYSIOLOGY.\n\n    [_First published in_ The National Review _for October,_ 1857_,\n    under the title of \"The Ultimate Laws of Physiology\". The title\n    \"Transcendental Physiology\", which the editor did not approve, was\n    restored when the essay was re-published with others in_ 1857.]\n\n\nThe title Transcendental Anatomy is used to distinguish that division of\nbiological science which treats, not of the structures of individual\norganisms considered separately, but of the general principles of\nstructure common to vast and varied groups of organisms,--the unity of\nplan discernible throughout multitudinous species, genera, and orders,\nwhich differ widely in appearance. And here, under the head of\nTranscendental Physiology, we purpose putting together sundry laws of\ndevelopment and function which hold not of particular kinds or classes\nof organisms, but of all organisms: laws, some of which have not, we\nbelieve, been hitherto enunciated.\n\nBy way of unobtrusively introducing the general reader to biological\ntruths of this class, let us begin by noticing one or two with which he\nis familiar. Take first, the relation between the activity of an organ\nand its growth. This is a universal relation. It holds, not only of a\nbone, a muscle, a nerve, an organ of sense, a mental faculty; but of\nevery gland, every viscus, every element of the body. It is seen, not in\nman only, but in each animal which affords us adequate opportunity of\ntracing it. Always providing that the performance of function is not so\nexcessive as to produce disorder, or to exceed the repairing powers\neither of the system at large or of the particular agencies by which\nnutriment is brought to the organ,--always providing this, it is a law\nof organized bodies that, other things equal, development varies as\nfunction. On this law are based all maxims and methods of right\neducation, intellectual, moral, and physical; and when statesmen are\nwise enough to see it, this law will be found to underlie all right\nlegislation.\n\nAnother truth co-extensive with the organic world, is that of hereditary\ntransmission. It is not, as commonly supposed, that hereditary\ntransmission is exemplified merely in re-appearance of the family\npeculiarities displayed by immediate or remote progenitors. Nor does the\nlaw of hereditary transmission comprehend only such more general facts\nas that modified plants or animals become the parents of permanent\nvarieties; and that new kinds of potatoes, new breeds of sheep, new\nraces of men, have been thus originated. These are but minor\nexemplifications of the law. Understood in its entirety, the law is that\neach plant or animal produces others of like kind with itself: the\nlikeness of kind consisting not so much in the repetition of individual\ntraits as in the assumption of the same general structure. This truth\nhas been made by daily illustration so familiar as nearly to have lost\nits significance. That wheat produces wheat,--that existing oxen are\ndescended from ancestral oxen,--that every unfolding organism ultimately\ntakes the form of the class, order, genus, and species from which it\nsprang; is a fact which, by force of repetition, has assumed in our\nminds the character of a necessity. It is in this, however, that the law\nof hereditary transmission is principally displayed; the phenomena\ncommonly named as exemplifying it being quite subordinate\nmanifestations. And the law, as thus understood, is universal. Not\nforgetting the apparent, but only apparent, exceptions presented by the\nstrange class of phenomena known as \"alternate generation,\" the truth\nthat like produces like is common to all types of organisms.\n\nLet us take next a universal physiological law of a less conspicuous\nkind. To the ordinary observer, it seems that the multiplication of\norganisms proceeds in various ways. He sees that the young of the higher\nanimals when born resemble their parents; that birds lay eggs, which\nthey foster and hatch; that fish deposit spawn and leave it. Among\nplants, he finds that while in some cases new individuals grow from\nseeds only, in other cases they also grow from tubers; that by certain\nplants layers are sent out, take root, and develop new individuals; and\nthat many plants can be reproduced from cuttings. Further, in the mould\nthat quickly covers stale food, and the infusoria that soon swarm in\nwater exposed to air and light, he sees a mode of generation which,\nseeming inexplicable, he is apt to consider \"spontaneous.\" The reader of\npopular science thinks the modes of reproduction still more various. He\nlearns that whole tribes of creatures multiply by gemmation--by a\ndevelopment from the body of the parent of buds which, after unfolding\ninto the parental form, separate and lead independent lives. Concerning\nmicroscopic forms of both animal and vegetal life, he reads that the\nordinary mode of multiplication is by spontaneous fission--a splitting\nup of the original individual into two or more individuals, which by and\nby severally repeat the process. Still more remarkable are the cases in\nwhich, as in the _Aphis_, an egg gives rise to an imperfect female, from\nwhich other imperfect females are born viviparously, grow, and in their\nturns bear other imperfect females; and so on for eight, ten, or more\ngenerations, until finally, perfect males and females are viviparously\nproduced. But now under all these, and many more, modified modes of\nmultiplication, the physiologist finds complete uniformity. The\nstarting-point, not only of every higher animal or plant, but of every\nclan of organisms which by fission or gemmation have sprung from a\nsingle organism, is always a spore, seed, or ovum. The millions of\ninfusoria or of aphides which, by sub-division or gemmation, have\nproceeded from one individual; the countless plants which have been\nsuccessively propagated from one original plant by cuttings or tubers;\nare, in common with the highest creature, primarily descended from a\nfertilized germ. And in all cases--in the humblest alga as in the oak,\nin the protozoon as in the mammal--this fertilized germ results from the\nunion of the contents of two cells. Whether, as among the lowest forms\nof life, these two cells are seemingly identical in nature; or whether,\nas among higher forms, they are distinguishable into sperm-cell and\ngerm-cell; it remains throughout true that from their combination\nresults the mass out of which is evolved a new organism or new series of\norganisms. That this law is without exception we are not prepared to\nsay; for in the case of the _Aphis_ certain experiments are thought to\nimply that under special conditions the descendants of an original\nindividual may continue multiplying for ever, without further\nfecundation. But we know of no case where it _actually is_ so; for\nalthough there are certain plants of which the seeds have never been\nseen, it is more probable that our observations are in fault than that\nthese plants are exceptions. And until we find undoubted exceptions, the\nabove-stated induction must stand. Here, then, we have another of the\ntruths of Transcendental Physiology: a truth which, so far as we know,\n_transcends_ all distinctions of genus, order, class, kingdom, and\napplies to every living thing.\n\nYet another generalization of like universality expresses the process of\norganic development. To the ordinary observer there seems no unity in\nthis. No obvious parallelism exists between the unfolding of a plant and\nthe unfolding of an animal. There is no manifest similarity between the\ndevelopment of a mammal, which proceeds without break from its first to\nits last stage, and that of an insect, which is divided into\nstrongly-marked stages--egg, larva, pupa, imago. Nevertheless it is now\nan established fact, that all organisms are evolved after one general\nmethod. At the outset the germ of every plant or animal is relatively\nhomogeneous; and advance towards maturity is advance towards greater\nheterogeneity. Each organized thing commences as an almost structureless\nmass, and reaches its ultimate complexity by the establishment of\ndistinctions upon distinctions,--by the divergence of tissues from\ntissues and organs from organs. Here, then, we have yet another\nbiological law of transcendent generality.\n\nHaving thus recognized the scope of Transcendental Physiology as\npresented in its leading truths, we are prepared for the considerations\nthat are to follow.\n\n       *       *       *       *       *\n\nAnd first, returning to the last of the great generalizations above\ngiven, let us inquire more nearly how this change from the homogeneous\nto the heterogeneous is carried on. Usually it is said to result from\nsuccessive differentiations. This, however, cannot be considered a\ncomplete account of the process. During the evolution of an organism\nthere occur, not only separations of parts, but coalescences of parts.\nThere is not only segregation, but aggregation. The heart, at first a\nsimple pulsating blood-vessel, by and by twists upon itself and becomes\nintegrated. The bile-cells constituting the rudimentary liver, do not\nmerely diverge from the surface of the intestine in which they at first\nform a simple layer; but they simultaneously consolidate into a definite\norgan. And the gradual concentration seen in these and other cases is a\npart of the developmental process--a part which, though more or less\nrecognized by Milne-Edwards and others, does not seem to have been\nincluded as an essential element in it.\n\nThis progressive integration, manifest alike when tracing up the several\nstages passed through by every embryo, and when ascending from the lower\norganic forms to the higher, may be most conveniently studied under\nseveral heads. Let us consider first what may be called _longitudinal\nintegration_.\n\nThe lower _Annulosa_--worms, myriapods, &c.--are characterized by the\ngreat numbers of segments of which they respectively consist, reaching\nin some cases to several hundreds; but as we advance to the higher\n_Annulosa_--centipedes, crustaceans, insects, spiders,--we find these\nnumbers greatly reduced, down to twenty-two, thirteen, and even fewer;\nand accompanying this there is a shortening or integration of the whole\nbody, reaching its extreme in crabs and spiders. Similarly with the\ndevelopment of an individual crustacean or insect. The thorax of a\nlobster, which, in the adult, forms, with the head, one compact box\ncontaining the viscera, is made up by the union of a number of segments\nwhich in the embryo were separable. The thirteen distinct divisions seen\nin the body of a caterpillar, become further integrated in the\nbutterfly: several segments are consolidated to form the thorax, and the\nabdominal segments are more aggregated than they originally were. The\nlike truth is seen when we pass to the internal organs. In the lower\nannulose forms, and in the larvae of the higher ones, the alimentary\ncanal consists either of a tube that is uniform from end to end, or else\nbulges into a succession of stomachs, one to each segment; but in the\ndeveloped forms there is a single well-defined stomach. In the nervous,\nvascular, and respiratory systems a parallel concentration may be\ntraced. Again, in the development of the _Vertebrata_ we have sundry\nexamples of longitudinal integration. The coalescence of several\nsegmental groups of bones to form the skull is one instance of it. It is\nfurther illustrated in the _os coccygis_, which results from the fusion\nof a number of caudal vertebrae. And in the consolidation of the sacral\nvertebrae of a bird it is also well exemplified.\n\nThat which we may distinguish as _transverse integration_, is well\nillustrated among the _Annulosa_ in the development of the nervous\nsystem. Leaving out those simple forms which do not present distinct\nganglia, it is to be observed that the lower annulose animals, in common\nwith the larvae of the higher, are severally characterized by a double\nchain of ganglia running from end to end of the body; while in the more\nadvanced annulose animals this double chain becomes a single chain. Mr.\nNewport has described the course of this concentration in insects; and\nby Rathke it has been traced in crustaceans. In the early stages of the\n_Astacus fluviatilis_, or common cray-fish, there is a pair of separate\nganglia to each ring. Of the fourteen pairs belonging to the head and\nthorax, the three pairs in advance of the mouth consolidate into one\nmass to form the brain, or cephalic ganglion. Meanwhile out of the\nremainder, the first six pairs severally unite in the median line, while\nthe rest remain more or less separate. Of these six double ganglia thus\nformed, the anterior four coalesce into one mass; the remaining two\ncoalesce into another mass; and then these two masses coalesce into one.\nHere we see longitudinal and transverse integration going on\nsimultaneously; and in the highest crustaceans they are both carried\nstill further. The _Vertebrata_ exhibit this transverse integration in\nthe development of the generative system. The lowest of the\nmammalia--the _Monotremata_--in common with birds, have oviducts which\ntowards their lower extremities are dilated into cavities severally\nperforming in an imperfect way the function of a uterus. \"In the\n_Marsupialia_, there is a closer approximation of the two lateral sets\nof organs on the median line; for the oviducts converge towards one\nanother and meet (without coalescing) on the median line; so that their\nuterine dilatations are in contact with each other, forming a true\n'double uterus.' ... As we ascend the series of 'placental' mammals, we\nfind the lateral coalescence becoming gradually more and more\ncomplete.... In many of the _Rodentia_, the uterus still remains\ncompletely divided into two lateral halves; whilst in others, these\ncoalesce at their lower portion, forming a rudiment of the true 'body'\nof the uterus in the Human subject. This part increases at the expense\nof the lateral 'cornua' in the higher Herbivora and Carnivora; but even\nin the lower Quadrumana, the uterus is somewhat cleft at its\nsummit.\"[6] And this process of transverse integration, which is still\nmore striking when observed in its details, is accompanied by parallel\nthough less important changes in the opposite sex. Once more; in the\nincreasing commissural connexion of the cerebral hemispheres, which,\nthough separate in the lower vertebrata, become gradually more united in\nthe higher, we have another instance. And further ones of a different\norder, but of like general implication, are supplied by the vascular\nsystem.\n\nNow it seems to us that the various kinds of integration here\nexemplified, which are commonly set down as so many independent\nphenomena, ought to be generalized, and included in the formula\ndescribing the process of development. The fact that in an adult crab,\nmany pairs of ganglia originally separate have become fused into a\nsingle mass, is a fact only second in significance to the\ndifferentiation of its alimentary canal into stomach and intestine. That\nin the higher _Annulosa_, a single heart replaces the string of\nrudimentary hearts constituting the dorsal blood-vessel in the lower\n_Annulosa_, (reaching in one species to the number of one hundred and\nsixty), is a truth as much needing to be comprised in the history of\nevolution, as is the formation of a respiratory surface by a branched\nexpansion of the skin. A right conception of the genesis of a vertebral\ncolumn, includes not only the differentiations from which result the\n_chorda dorsalis_ and the vertebral segments imbedded in it; but quite\nas much it includes the coalescence of numerous vertebral processes with\ntheir respective vertebral bodies. The changes in virtue of which\nseveral things become one, demand recognition equally with those in\nvirtue of which one thing becomes several. Evidently, then, the current\nstatement which ascribes the developmental progress to differentiations\nalone, is incomplete. Adequately to express the facts, we must say\nthat the transition from the homogeneous to the heterogeneous is carried\non by differentiations and accompanying integrations.\n\nIt may not be amiss here to ask--What is the meaning of these\nintegrations? The evidence seems to show that they are in some way\ndependent on community of function. The eight segments which coalesce to\nmake the head of a centipede, jointly protect the cephalic ganglion, and\nafford a solid fulcrum for the jaws, &c. The many bones which unite to\nform a vertebral skull have like uses. In the consolidation of the\nseveral pieces which constitute a mammalian pelvis, and in the\nanchylosis of from ten to nineteen vertebrae in the sacrum of a bird, we\nhave kindred instances of the integration of parts which transfer the\nweight of the body to the legs. The more or less extensive fusion of the\ntibia with the fibula and the radius with the ulna in the ungulated\nmammals, whose habits require only partial rotations of the limbs, is a\nfact of like meaning. And all the instances lately given--the\nconcentration of ganglia, the replacement of many pulsating blood-sacs\nby fewer and finally by one, the fusion of two uteri into a single\nuterus--have the same implication. Whether, as in some cases, the\nintegration is merely a consequence of the growth which eventually\nbrings into contact adjacent parts performing similar duties; or\nwhether, as in other cases, there is an actual approximation of these\nparts before their union; or whether, as in yet other cases, the\nintegration is of that indirect kind which arises when, out of a number\nof like organs, one, or a group, discharges an ever-increasing share of\nthe common function, and so grows while the rest dwindle and\ndisappear;--the general fact remains the same, that there is a tendency\nto the unification of parts having similar duties.\n\nThe tendency, however, acts under limiting conditions; and recognition\nof them will explain some apparent exceptions. In the human foetus, as\nin the lower vertebrata, the eyes are placed one on each side of the\nhead. During evolution they become relatively nearer, and at birth are\nin front; though they are still, in the European infant as in the adult\nMongol, proportionately further apart than they afterwards become. But\nthis approximation shows no signs of further increase. Two reasons\nsuggest themselves. One is that the two eyes have not quite the same\nfunction, since they are directed to slightly-different aspects of each\nobject looked at; and, since the resulting binocular vision has an\nadvantage over monocular vision, there results a check upon further\napproach towards identity of function and unity of structure. The other\nreason is that the interposed structures do not admit of any nearer\napproach. For the orbits of the eyes to be brought closer together,\nwould imply a decrease in the olfactory chambers; and as these are\nprobably not larger than is demanded by their present functional\nactivity, no decrease can take place. Again, if we trace up the external\norgans of smell through fishes,[7] reptiles, ungulate mammals and\nunguiculate mammals, to man, we perceive a general tendency to\ncoalescence in the median line; and on comparing the savage with the\ncivilized, or the infant with the adult, we see this approach of the\nnostrils carried furthest in the most perfect of the species. But since\nthe septum which divides them has the function both of an evaporating\nsurface for the lachrymal secretion, and of a ramifying surface for a\nnerve ancillary to that of smell, it does not disappear entirely: the\nintegration remains incomplete. These and other like instances do not\nhowever militate against the hypothesis. They merely show that the\ntendency is sometimes antagonized by other tendencies. Bearing in mind\nwhich qualification, we may say, that as differentiation of parts is\nconnected with difference of function, so there appears to be a\nconnexion between integration of parts and sameness of function.\n\n       *       *       *       *       *\n\nClosely related to the general truth that the evolution of all organisms\nis carried on by combined differentiations and integrations, is another\ngeneral truth, which physiologists appear not to have recognized. When\nwe look at the organic world as a whole, we may observe that, on passing\nfrom lower to higher forms, we pass to forms which are not only\ncharacterized by a greater differentiation of parts, but are at the same\ntime more completely differentiated from the surrounding medium. This\ntruth may be contemplated under various aspects.\n\nIn the first place it is illustrated in _structure_. The advance from\nthe homogeneous to the heterogeneous itself involves an increasing\ndistinction from the inorganic world. In the lowest _Protozoa_, as some\nof the Rhizopods, we have a homogeneity approaching to that of air,\nwater, or earth; and the ascent to organisms of greater and greater\ncomplexity of structure, is an ascent to organisms which are in that\nrespect more strongly contrasted with the relatively structureless\nmasses in the environment.\n\nIn _form_ again we see the same truth. A general characteristic of\ninorganic matter is its indefiniteness of form, and this is also a\ncharacteristic of the lower organisms, as compared with the higher.\nSpeaking generally, plants are less definite than animals, both in shape\nand size--admit of greater modifications from variations of position and\nnutrition. Among animals, the _Amoeba_ and its allies are not only\nalmost structureless, but are amorphous; and the irregular form is\nconstantly changing. Of the organisms resulting from the aggregation of\namoeba-like creatures, we find that while some assume a certain\ndefiniteness of form, in their compound shells at least, others, as the\nSponges, are irregular. In the Zoophytes and in the _Polyzoa_, we see\ncompound organisms, most of which have modes of growth not more\ndeterminate than those of plants. But among the higher animals, we find\nnot only that the mature shape of each species is quite definite, but\nthat the individuals of each species differ very little in size.\n\nA parallel increase of contrast is seen in _chemical composition_. With\nbut few exceptions, and those only partial ones, the lowest animal and\nvegetal forms are inhabitants of the water; and water is almost their\nsole constituent. Dessicated _Protophyta_ and _Protozoa_ shrink into\nmere dust; and among the acalephes we find but a few grains of solid\nmatter to a pound of water. The higher aquatic plants, in common with\nthe higher aquatic animals, possessing as they do much greater tenacity\nof substance, also contain a greater proportion of the organic elements;\nand so are chemically more unlike their medium. And when we pass to the\nsuperior classes of organisms--land plants and land animals--we find\nthat, chemically considered, they have little in common either with the\nearth on which they stand or the air which surrounds them.\n\nIn _specific gravity_, too, we may note the like. The very simplest\nforms, in common with the spores and gemmules of the higher ones, are as\nnearly as may be of the same specific gravity as the water in which they\nfloat; and though it cannot be said that among aquatic creatures\nsuperior specific gravity is a standard of general superiority, yet we\nmay fairly say that the superior orders of them, when divested of the\nappliances by which their specific gravity is regulated, differ more\nfrom water in their relative weights than do the lower. In terrestrial\norganisms, the contrast becomes extremely marked. Trees and plants, in\ncommon with insects, reptiles, mammals, birds, are all of a specific\ngravity considerably less than the earth and immensely greater than the\nair.\n\nWe see the law similarly fulfilled in respect of _temperature_. Plants\ngenerate but an extremely small quantity of heat, which is to be\ndetected only by delicate experiments; and practically they may be\nconsidered as being in this respect like their environment. Aquatic\nanimals rise very little above the surrounding water in temperature:\nthat of the invertebrata being mostly less than a degree above it, and\nthat of fishes not exceeding it by more than two or three degrees, save\nin the case of some large red-blooded fishes, as the tunny, which exceed\nit by nearly ten degrees. Among insects, the range is from two to ten\ndegrees above that of the air: the excess varying according to their\nactivity. The heat of reptiles is from four to fifteen degrees more than\nthat of their medium. While mammals and birds maintain a heat which\ncontinues almost unaffected by external variations, and is often greater\nthan that of the air by seventy, eighty, ninety, and even a hundred\ndegrees.\n\nOnce more, in greater _self-mobility_ a progressive differentiation is\ntraceable. Dead matter is inert: some form of independent motion is our\nmost general test of life. Passing over the indefinite border-land\nbetween the animal and vegetable kingdoms, we may roughly class plants\nas organisms which, while they exhibit the kind of motion implied in\ngrowth, are not only without locomotive power, but in nearly all cases\nare without the power of moving their parts in relation to one another;\nand thus are less differentiated from the inorganic world than animals.\nThough in those microscopic _Protophyta_ and _Protozoa_ inhabiting the\nwater--the spores of algae, the gemmules of sponges, and the infusoria\ngenerally--we see locomotion produced by ciliary action; yet this\nlocomotion, while rapid relatively to their sizes, is absolutely slow.\nOf the _Coelenterata_, a great part are either permanently rooted or\nhabitually stationary, and so have scarcely any self-mobility but that\nimplied in the relative movements of parts; while the rest, of which the\ncommon jelly-fish serves as a sample, have mostly but little ability to\nmove themselves through the water. Among the higher aquatic\n_Invertebrata_,--cuttle-fishes and lobsters, for instance,--there is a\nvery considerable power of locomotion; and the aquatic _Vertebrata_ are,\nconsidered as a class, much more active in their movements than the\nother inhabitants of the water. But it is only when we come to\nair-breathing creatures that we find the vital characteristic of\nself-mobility manifested in the highest degree. Flying insects, mammals,\nbirds, travel with velocities far exceeding those attained by any of the\nlower classes of animals; and so are more strongly contrasted with their\ninert environments.\n\nThus, on contemplating the various grades of organisms in their\nascending order, we find them more and more distinguished from their\ninanimate media in _structure_, in _form_, in _chemical composition_, in\n_specific gravity_, in _temperature_, in _self-mobility_. It is true\nthat this generalization does not hold with regularity. Organisms which\nare in some respects the most strongly contrasted with the inorganic\nworld, are in other respects less contrasted than inferior organisms. As\na class, mammals are higher than birds; and yet they are of lower\ntemperature, and have smaller powers of locomotion. The stationary\noyster is of higher organization than the free-swimming medusa; and the\ncold-blooded and less heterogeneous fish is quicker in its movements\nthan the warm-blooded and more heterogeneous sloth. But the admission\nthat the several aspects under which this increasing contrast shows\nitself bear variable ratios to one another, does not negative the\ngeneral truth enunciated. Looking at the facts in the mass, it cannot be\ndenied that the successively higher groups of organisms are severally\ncharacterized, not only by greater differentiation of parts, but also by\ngreater differentiation from the surrounding medium in sundry other\nphysical attributes. It would seem that this peculiarity has some\nnecessary connexion with superior vital manifestations. One of those\nlowly gelatinous forms which are some of them so transparent and\ncolourless as to be with difficulty distinguished from the water they\nfloat in, is not more like its medium in chemical, mechanical, optical,\nthermal, and other properties, than it is in the passivity with which it\nsubmits to all the actions brought to bear on it; while the mammal does\nnot more widely differ from inanimate things in these properties than it\ndoes in the activity with which it meets surrounding changes by\ncompensating changes in itself. Between these two extremes, we see a\ntolerably constant ratio between these two kinds of contrast. In\nproportion as an organism is physically like its environment it remains\na passive partaker of the changes going on in its environment; while in\nproportion as it is endowed with powers of counteracting such changes,\nit exhibits greater unlikeness to its environment.\n\n       *       *       *       *       *\n\nThus far we have proceeded inductively, in conformity with established\nusage; but it seems to us that much may be done in this and other\ndepartments of biologic inquiry by pursuing the deductive method. The\ngeneralizations at present constituting the science of physiology, both\ngeneral and special, have been reached _a posteriori_; but certain\nfundamental data have now been discovered, starting from which we may\nreason our way _a priori_, not only to some of the truths that have been\nascertained by observation and experiment, but also to some others. The\npossibility of such _a priori_ conclusions will be at once recognized on\nconsidering some familiar cases.\n\nChemists have shown that a necessary condition to vital activity in\nanimals is oxidation of certain matters contained in the body either as\ncomponents or as waste products. The oxygen requisite for this oxidation\nis contained in the surrounding medium--air or water, as the case may\nbe. If the organism be minute, mere contact of its external surface with\nthe oxygenated medium achieves the requisite oxidation; but if the\norganism is bulky, and so exposes a surface which is small in\nproportion to its mass, any considerable oxidation cannot be thus\nachieved. One of two things is therefore implied. Either this bulky\norganism, receiving no oxygen but that absorbed through its integument,\nmust possess but little vital activity; or else, if it possesses much\nvital activity, there must be some extensive ramified surface, internal\nor external, through which adequate aeration may take place--a\nrespiratory apparatus. That is to say, lungs, or gills, or branchiae, or\ntheir equivalents, are predicable _a priori_ as possessed by all active\ncreatures of any size.\n\nSimilarly with respect to nutriment. There are _entozoa_ which, living\nin the insides of other animals, and being constantly bathed by\nnutritive fluids, absorb a sufficiency through their outer surfaces; and\nso have no need of stomachs, and do not possess them. But all other\nanimals, inhabiting media that are not in themselves nutritive, but only\ncontain masses of food here and there, must have appliances by which\nthese masses of food may be utilized. Evidently mere external contact of\na solid organism with a solid portion of nutriment, could not result in\nthe absorption of it in any moderate time, if at all. To effect\nabsorption, there must be both a solvent or macerating action, and an\nextended surface fit for containing and imbibing the dissolved products:\nthere must be a digestive cavity. Thus, given the ordinary conditions of\nanimal life, and the possession of stomachs by all creatures living\nunder these conditions may be deductively known.\n\nCarrying out the train of reasoning still further, we may infer the\nexistence of a vascular system or something equivalent to it, in all\ncreatures of any size and activity. In a comparatively small inert\nanimal, such as the hydra, which consists of little more than a sac\nhaving a double wall--an outer layer of cells forming the skin, and an\ninner layer forming the digestive and absorbent surface--there is no\nneed for a special apparatus to diffuse through the body the aliment\ntaken up; for the body is little more than a wrapper to the food it\nencloses. But where the bulk is considerable, or where the activity is\nsuch as to involve much waste and repair, or where both these\ncharacteristics exist, there is a necessity for a system of\nblood-vessels. It is not enough that there be adequately extensive\nsurfaces for absorption and aeration; for in the absence of any means of\nconveyance, the absorbed elements can be of little or no use to the\norganism at large. Evidently there must be channels of communication.\nWhen, as in the _Medusae_, we find these channels of communication\nconsisting simply of branched canals opening out of the stomach and\nspreading through the disk, we may know, _a priori_, that such creatures\nare comparatively inactive; seeing that the nutritive liquid thus\npartially distributed throughout their bodies is crude and dilute, and\nthat there is no efficient appliance for keeping it in motion.\nConversely, when we meet with a creature of considerable size which\ndisplays much vivacity, we may know, _a priori_, that it must have an\napparatus for the unceasing supply of concentrated nutriment, and of\noxygen, to every organ--a pulsating vascular system.\n\nIt is manifest, then, that setting out from certain known fundamental\nconditions to vital activity, we may deduce from them sundry of the\nchief characteristics of organized bodies. Doubtless these known\nfundamental conditions have been inductively established. But what we\nwish to show is that, given these inductively-established primary facts\nin physiology, we may with safety draw certain general deductions from\nthem. And, indeed, the legitimacy of such deductions, though not\nformally acknowledged, is practically recognized in the convictions of\nevery physiologist, as may be readily proved. Thus, were a physiologist\nto find a creature exhibiting complex and variously co-ordinated\nmovements, and yet having no nervous system; he would be less astonished\nat the breach of his empirical generalization that all such creatures\nhave nervous systems, than at the disproof of his unconscious deduction\nthat all creatures exhibiting complex and variously co-ordinated\nmovements must have an \"internuncial\" apparatus by which the\nco-ordination may be effected. Or were he to find a creature having\nblood rapidly circulated and rapidly aerated, but yet showing a low\ntemperature, the proof so afforded that active change of matter is not,\nas he had inferred from chemical data, the cause of animal heat, would\nstagger him more than would the exception to a constantly-observed\nrelation. Clearly, then, the _a priori_ method already plays a part in\nphysiological reasoning. If not ostensibly employed as a means of\nreaching new truths, it is at least privately appealed to for\nconfirmation of truths reached _a posteriori_.\n\nBut the illustrations above given go far to show, that it may to a\nconsiderable extent be safely used as an independent instrument of\nresearch. The necessities for a nutritive system, a respiratory system,\nand a vascular system, in all animals of size and vivacity, seem to us\nlegitimately inferable from the conditions to continued vital activity.\nGiven the physical and chemical data, and these structural peculiarities\nmay be deduced with as much certainty as may the hollowness of an iron\nball from its power of floating in water.\n\nIt is not, of course, asserted that the more _special_ physiological\ntruths can be deductively reached. The argument by no means implies\nthis. Legitimate deduction presupposes adequate data; and in respect to\nthe _special_ phenomena of organic growth, structure, and function,\nadequate data are unattainable, and will probably ever remain so. It is\nonly in the case of the more _general_ physiological truths, such as\nthose above instanced, where we have something like adequate data, that\ndeductive reasoning becomes possible.\n\nAnd here is reached the stage to which the foregoing considerations are\nintroductory. We propose now to show that there are certain still more\ngeneral attributes of organized bodies, which are deducible from certain\nstill more general attributes of things.\n\n       *       *       *       *       *\n\nIn an essay on \"Progress: its Law and Cause,\" elsewhere published,[8] we\nhave endeavoured to show that the transformation of the homogeneous into\nthe heterogeneous, in which all progress, organic or other, essentially\nconsists, is consequent on the production of many effects by one\ncause--many changes by one force. Having pointed out that this is a law\nof all things, we proceeded to show deductively that the multiform\nevolutions of the homogeneous into the heterogeneous--astronomic,\ngeologic, ethnologic, social, &c.,--were explicable as consequences. And\nthough in the case of organic evolution, lack of data disabled us from\nspecifically tracing out the progressive complication as due to the\nmultiplication of effects; yet, we found sundry indirect evidences that\nit was so. Now in so far as this conclusion, that organic evolution\nresults from the decomposition of each expended force into several\nforces, was inferred from the general law previously pointed out, it was\nan example of deductive physiology. The particular was concluded from\nthe universal.\n\nWe here propose in the first place to show, that there is another\ngeneral truth closely connected with the above; and in common with it\nunderlying explanations of all progress, and therefore the progress of\norganisms--a truth which may indeed be considered as taking precedence\nof it in respect of time, if not in respect of generality. This truth\nis, that _the condition of homogeneity is a condition of unstable\nequilibrium_.\n\nThe phrase _unstable equilibrium_ is one used in mechanics to express\na balance of forces of such kind, that the interference of any further\nforce, however minute, will destroy the arrangement previously existing,\nand bring about a different arrangement. Thus, a stick poised on its\nlower end is in unstable equilibrium: however exactly it may be placed\nin a perpendicular position, as soon as it is left to itself it begins,\nat first imperceptibly and then visibly, to lean on one side, and with\nincreasing rapidity falls into another position. Conversely, a stick\nsuspended from its upper end is in stable equilibrium: however much\ndisturbed, it will return to the same position. Our meaning is, then,\nthat the state of homogeneity, like the state of the stick poised on its\nlower end, is one that cannot be maintained; and that hence results the\nfirst step in its gravitation towards the heterogeneous. Let us take a\nfew illustrations.\n\nOf mechanical ones the most familiar is that of the scales. If\naccurately made and not clogged by dirt or rust, a pair of scales cannot\nbe perfectly balanced: eventually one scale will descend and the other\nascend--they will assume a heterogeneous relation. Again, if we sprinkle\nover the surface of a liquid a number of equal-sized particles, having\nan attraction for one another, they will, no matter how uniformly\ndistributed, by and by concentrate irregularly into groups. Were it\npossible to bring a mass of water into a state of perfect homogeneity--a\nstate of complete quiescence, and exactly equal density throughout--yet\nthe radiation of heat from neighbouring bodies, by affecting differently\nits different parts, would soon produce inequalities of density and\nconsequent currents; and would so render it to that extent\nheterogeneous. Take a piece of red-hot matter, and however evenly heated\nit may at first be, it will quickly cease to be so: the exterior,\ncooling faster than the interior, will become different in temperature\nfrom it. And the lapse into heterogeneity of temperature, so obvious in\nthis extreme case, is ever taking place more or less in all cases. The\nactions of chemical forces supply other illustrations. Expose a\nfragment of metal to air or water, and in course of time it will be\ncoated with a film of oxide, carbonate, or other compound: its outer\nparts will become unlike its inner parts. Thus, every homogeneous\naggregate of matter tends to lose its balance in some way or\nother--either mechanically, chemically, thermally or electrically; and\nthe rapidity with which it lapses into a non-homogeneous state is simply\na question of time and circumstances. Social bodies illustrate the law\nwith like constancy. Endow the members of a community with equal\nproperties, positions, powers, and they will forthwith begin to slide\ninto inequalities. Be it in a representative assembly, a railway board,\nor a private partnership, the homogeneity, though it may continue in\nname, inevitably disappears in reality.\n\nThe instability thus variously illustrated becomes still more manifest\nif we consider its rationale. It is consequent on the fact that the\nseveral parts of any homogeneous mass are necessarily exposed to\ndifferent forces--forces which differ either in their kinds or amounts;\nand being exposed to different forces they are of necessity differently\nmodified. The relations of outside and inside, and of comparative\nnearness to neighbouring sources of influence, imply the reception of\ninfluences which are unlike in quantity or quality or both; and it\nfollows that unlike changes will be wrought in the parts dissimilarly\nacted upon. The unstable equilibrium of any homogeneous aggregate can\nthus be shown both inductively and deductively.\n\nAnd now let us consider the bearing of this general truth on the\nevolution of organisms. The germ of a plant or animal is one of these\nhomogeneous aggregates--relatively homogeneous if not absolutely\nso--whose equilibrium is unstable. But it has not simply the ordinary\ninstability of homogeneous aggregates: it has something more. For it\nconsists of units which are themselves specially characterized by\ninstability. The constituent molecules of organic matter are\ndistinguished by the feebleness of the affinities which hold their\ncomponent elements together. They are extremely sensitive to heat,\nlight, electricity, and the chemical actions of foreign elements; that\nis, they are peculiarly liable to be modified by disturbing forces.\nHence then it follows, _a priori_, that a homogeneous aggregate of these\nunstable molecules will have an excessive tendency to lose its\nequilibrium. It will have a quite special liability to lapse into a\nnon-homogeneous state. It will rapidly gravitate towards heretogeneity.\n\nMoreover, the process must repeat itself in each of the subordinate\ngroups of organic units which are differentiated by the modifying\nforces. Each of these subordinate groups, like the original group, must\ngradually, in obedience to the influences acting on it, lose its balance\nof parts--must pass from a uniform into a multiform state. And so on\ncontinuously.\n\nThus, starting from the general laws of things, and the known chemical\nattributes of organic matter, we may conclude deductively that the\nhomogeneous germs of organisms have a peculiar proclivity towards a\nnon-homogeneous state; which may be either the state we call\ndecomposition, or the state we call organization.\n\n       *       *       *       *       *\n\nAt present we have reached a conclusion only of the most general nature.\nWe merely learn that _some_ kind of heterogeneity is inevitable; but as\nyet there is nothing to tell us _what_ kind. Besides that _orderly_\nheterogeneity which distinguishes organisms, there is the _disorderly_\nor _chaotic_ heterogeneity, into which a loose mass of inorganic matter\nlapses; and at present no reason has been given why the homogeneous germ\nof a plant or animal should not lapse into the disorderly instead of the\norderly heterogeneity. But by pursuing still further the line of\nargument hitherto followed we shall find a reason.\n\nWe have seen that the instability of homogeneous aggregates in general,\nand of organic ones in particular, is consequent on the various ways and\ndegrees in which their constituent parts are exposed to the disturbing\nforces brought to bear on them: their parts are differently acted upon,\nand therefore become different. Manifestly, then, a rationale of the\nspecial changes which a germ undergoes, must be sought in the particular\nrelations which its several parts bear to each other and to their\nenvironment. However it may be masked, we may suspect the fundamental\nprinciple of organization to be, that the many like units forming a germ\nacquire those kinds and degrees of unlikeness which their respective\npositions entail.\n\nTake a mass of unorganized but organizable matter--either the body of\none of the lowest living forms, or the germ of one of the higher.\nConsider its circumstances. It is immersed in water or air; or it is\ncontained within a parent organism. Wherever placed, however, its outer\nand inner parts stand differently related to surrounding\nexistences--nutriment, oxygen, and the various stimuli. But this is not\nall. Whether it lies quiescent at the bottom of the water, whether it\nmoves through the water preserving some definite attitude, or whether it\nis in the inside of an adult; it equally results that certain parts of\nits surface are more directly exposed to surrounding agencies than other\nparts--in some cases more exposed to light, heat, or oxygen, and in\nothers to the maternal tissues and their contents. The destruction of\nits original equilibrium is therefore certain. It may take place in one\nof two ways. Either the disturbing forces may be such as to overbalance\nthe affinities of the organic elements, in which case there results that\nchaotic heterogeneity known as decomposition; or, as is ordinarily the\ncase, such changes are induced as do not destroy the organic compounds,\nbut only modify them: the parts most exposed to the modifying forces\nbeing most modified. Hence result those first differentiations which\nconstitute incipient organization. From the point of view thus reached,\nsuppose we look at a few cases: neglecting for the present all\nconsideration of the tendency to assume the inherited type.\n\nNote first what appear to be exceptions, as the _Amoeba_. In this\ncreature and its allies, the substance of the jelly-like body remains\nthroughout life unorganized--undergoes no permanent differentiations.\nBut this fact, which seems directly opposed to our inference, is really\none of the most significant evidences of its truth. For what is the\npeculiarity of the Rhizopods, exemplified by the _Amoeba_? They\nundergo perpetual and irregular changes of shape--they show no\npersistent relations of parts. What lately formed a portion of the\ninterior is now protruded, and, as a temporary limb, is attached to some\nobject it happens to touch. What is now a part of the surface will\npresently be drawn, along with the atom of nutriment sticking to it,\ninto the centre of the mass. Thus there is an unceasing interchange of\nplaces; and the relations of inner and outer have no settled existence.\nBut by the hypothesis, it is only in virtue of their unlike positions\nwith respect to modifying forces, that the originally-like units of a\nliving mass become unlike. We must not therefore expect any established\ndifferentiation of parts in creatures which exhibit no established\ndifferences of position in their parts.\n\nThis negative evidence is borne out by abundant positive evidence. When\nwe turn from these ever-changing specks of living jelly to organisms\nhaving unchanging distributions of substance, we find differences of\ntissue corresponding to differences of relative position. In all the\nhigher _Protozoa_, as also in the _Protophyta_, we meet with a\nfundamental differentiation into cell-membrane and cell-contents,\nanswering to that fundamental contrast of conditions implied by the\nwords outside and inside. And on passing from what are roughly classed\nas unicellular organisms to the lowest of those which consist of\naggregated cells, we equally observe the connexion between structural\ndifferences and differences of circumstance. In the sponge, permeated\nthroughout by currents of sea-water, the absence of definite\norganization corresponds with the absence of definite unlikeness of\nconditions. In the _Thalassicolla_ of Professor Huxley--a transparent,\ncolourless body, found floating passively at the surface of the sea, and\nconsisting essentially of \"a mass of cells united by jelly\"--there is\ndisplayed a rude structure obviously subordinated to the primary\nrelations of centre and surface: in all of its many and important\nvarieties, the parts exhibit a more or less concentric arrangement.\n\nAfter this primary modification, by which the outer tissues are\ndifferentiated from the inner, the next in order of constancy and\nimportance is that by which some part of the outer tissues is\ndifferentiated from the rest; and this corresponds with the almost\nuniversal fact that some part of the outer tissues is more directly\nexposed to certain environing influences than the rest. Here, as before,\nthe apparent exceptions are extremely significant. Some of the lowest\nvegetable organisms, as the _Hematococci_ and _Protococci_, evenly\nimbedded in a mass of mucus, or dispersed through the Arctic snow,\ndisplay no differentiations of surface: the several parts of the surface\nbeing subjected to no definite contrasts of conditions. The\n_Thalassicolla_ above mentioned, unfixed, and rolled about by the waves,\npresents all its sides successively to the same agencies; and all its\nsides are alike. A ciliated sphere like the _Volvox_ has no parts of its\nperiphery unlike other parts; and it is not to be expected that it\nshould have; seeing that as it revolves in all directions, it does not,\nin traversing the water, permanently expose any part to special\nconditions. But when we come to creatures that are either fixed, or\nwhile moving, severally preserve a definite attitude, we no longer find\nuniformity of surface. The gemmule of a Zoophyte, which during its\nlocomotive stage is distinguishable only into outer and inner tissues,\nno sooner takes root than its upper end begins to assume a different\nstructure from its lower. The free-swimming embryo of an aquatic\nannelid, being ovate and not ciliated all over, moves with one end\nforemost; and its differentiations proceed in conformity with this\ncontrast of circumstances.\n\nThe principle thus displayed in the humbler forms of life, is traceable\nduring the development of the higher; though being here soon masked by\nthe assumption of the hereditary type, it cannot be traced far. Thus the\n\"mulberry-mass\" into which a fertilized ovum of a vertebrate animal\nfirst resolves itself, soon begins to exhibit a difference between the\nouter and inner parts answering to the difference of circumstances. The\nperipheral cells, after reaching a more complete development than the\ncentral ones, coalesce into a membrane enclosing the rest; and then the\ncells lying next to these outer ones become aggregated with them, and\nincrease the thickness of the germinal membrane, while the central cells\nliquefy. Again, one part of the germinal membrane presently becomes\ndistinguishable as the germinal spot; and without asserting that the\ncause of this is to be found in the unlike relations which the\nrespective parts of the germinal membrane bear to environing influences,\nit is clear that we have in these unlike relations an element of\ndisturbance tending to destroy the original homogeneity of the germinal\nmembrane. Further, the germinal membrane by and by divides into two\nlayers, internal and external; the one in contact with the liquefied\ninterior part or yelk, the other exposed to the surrounding fluids: this\ncontrast of circumstances being in obvious correspondence with the\ncontrast of structures which follows it. Once more, the subsequent\nappearance of the vascular layer between these mucous and serous layers,\nas they have been named, admits of a like interpretation. And in this\nand the various complications which now begin to show themselves, we may\nsee coming into play that general law of the multiplication of effects\nflowing from one cause, to which the increase of heterogeneity was\nelsewhere ascribed.[9]\n\nConfining our remarks, as we do, to the most general facts of\ndevelopment, we think that some light is thus thrown on them. That the\nunstable equilibrium of a homogeneous germ must be destroyed by the\nunlike exposure of its several units to surrounding influences, is an _a\npriori_ conclusion. And it seems also to be an _a priori_ conclusion,\nthat the several units thus differently acted upon, must either be\ndecomposed, or must undergo such modifications of nature as may enable\nthem to live in the respective circumstances they are thrown into: in\nother words--_they must either die or become adapted to their\nconditions_. Indeed, we might infer as much without going through the\nforegoing train of reasoning. The superficial organic units (be they the\nouter cells of a \"mulberry-mass,\" or be they the outer molecules of an\nindividual cell) must assume the function which their position\nnecessitates; and assuming this function, must acquire such character as\nperformance of it involves. The layer of organic units lying in contact\nwith the yelk must be those through which the yelk is absorbed; and so\nmust be adapted to the absorbent office. On this condition only does the\nprocess of organization appear possible. We might almost say that just\nas some race of animals, which multiplies and spreads into divers\nregions of the earth, becomes differentiated into several races through\nthe adaptation of each to its conditions of life; so, the originally\nhomogeneous population of cells arising in a fertilized germ-cell,\nbecomes divided into several populations of cells that grow unlike in\nvirtue of the unlikeness of their circumstances.\n\nMoreover, it is to be remarked in further proof of our position, that it\nfinds its clearest and most abundant illustrations where the conditions\nof the case are the simplest and most general--where the phenomena are\nthe least involved: we mean in the production of individual cells. The\nstructures which presently arise round nuclei in a blastema, and which\nhave in some way been determined by those nuclei as centres of\ninfluence, evidently conform to the law; for the parts of the blastema\nin contact with the nuclei are differently conditioned from the parts\nnot in contact with them. Again, the formation of a membrane round each\nof the masses of granules into which the endochrome of an alga-cell\nbreaks up, is an instance of analogous kind. And should the\nrecently-asserted fact that cells may arise round vacuoles in a mass of\norganizable substance, be confirmed, another good example will be\nfurnished; for such portions of substance as bound these vacant spaces\nare subject to influences unlike those to which other portions of the\nsubstance are subject. If then we can most clearly trace this law of\nmodification in these primordial processes, as well as in those more\ncomplex but analogous ones exhibited in the early changes of an ovum, we\nhave strong reason for thinking that the law is fundamental.\n\nBut, as already more than once hinted, this principle, understood in the\nsimple form here presented, supplies no key to the detailed phenomena of\norganic development. It fails entirely to explain generic and specific\npeculiarities; and leaves us equally in the dark respecting those more\nimportant distinctions by which families and orders are marked out. Why\ntwo ova, similarly exposed in the same pool, should become the one a\nfish, and the other a reptile, it cannot tell us. That from two\ndifferent eggs placed under the same hen, should respectively come forth\na duckling and a chicken, is a fact not to be accounted for on the\nhypothesis above developed. Here we are obliged to fall back upon the\nunexplained principle of hereditary transmission. The capacity possessed\nby an unorganized germ of unfolding into a complex adult which repeats\nancestral traits in minute details, and that even when it has been\nplaced in conditions unlike those of its ancestors, is a capacity\nimpossible for us to understand. That a microscopic portion of seemingly\nstructureless matter should embody an influence of such kind, that the\nresulting man will in fifty years after become gouty or insane, is a\ntruth which would be incredible were it not daily illustrated. But\nthough the _manner_ in which hereditary likeness, in all its\ncomplications, is conveyed, is a mystery passing comprehension, it is\nquite conceivable that it is conveyed in subordination to the law of\nadaptation above explained; and we are not without reasons for thinking\nthat it is so. Various facts show that acquired peculiarities resulting\nfrom the adaptation of constitution to conditions, are transmissible to\noffspring. Such acquired peculiarities consist of differences of\nstructure or composition in one or more of the tissues. That is to say,\nof the aggregate of similar organic units composing a germ, the group\ngoing to the formation of a particular tissue, will take on the special\ncharacter which the adaptation of that tissue to new circumstances had\nproduced in the parents. We know this to be a general law of organic\nmodifications. Further, it is the _only_ law of organic modifications of\nwhich we have any evidence.[10] It is not impossible then that it is the\nuniversal law; comprehending not simply those minor modifications which\noffspring inherit from recent ancestry, but comprehending also those\nlarger modifications distinctive of species, genus, order, class, which\nthey inherit from antecedent races of organisms. And thus it _may be_\nthat the law of adaptation is the sole law; presiding not only over the\ndifferentiation of any race of organisms into several races, but also\nover the differentiation of the race of organic units composing a germ,\ninto the many races of organic units composing an adult. So understood,\nthe process gone through by every unfolding organism will consist,\npartly in the direct adaptation of its elements to their several\ncircumstances, and partly in the assumption of characters resulting from\nanalogous adaptations of the elements of all ancestral organisms.\n\nBut our argument does not commit us to any such far-reaching speculation\nas this; which we introduce simply as suggested by it, not involved. All\nwe are here concerned to show, is, that the deductive method aids us in\ninterpreting some of the more general phenomena of development. That all\nhomogeneous aggregates are in unstable equilibrium is a universal truth,\nfrom which is deducible the instability of every organic germ. From the\nknown sensitiveness of organic compounds to chemical, thermal, and other\ndisturbing forces, we further infer the _unusual_ instability of every\norganic germ--a proneness far beyond that of other homogeneous\naggregates to lapse into a heterogeneous state. By the same line of\nreasoning we are led to the additional inference, that the first\ndivisions into which a germ resolves itself, being severally in a state\nof unstable equilibrium, are similarly prone to undergo further changes;\nand so on continuously. Moreover, we have found it to be equally an _a\npriori_ conclusion, that as, in all other cases, the loss of homogeneity\nis due to the different degrees and kinds of force brought to bear on\nthe different parts; so, in this case too, difference of circumstances\nis the primary cause of differentiation. Add to which, that as the\nseveral changes undergone by the respective parts thus diversely acted\nupon, are changes which do not destroy their vital activity, they must\nbe changes which bring that vital activity into subordination to the\nincident forces--they must be adaptations; and the like must be in some\nsense true of all the subsequent changes. Thus by deductive reasoning we\nget some insight into the method of organization. However unable we are,\nand probably ever shall be, to comprehend the way in which a germ is\nmade to take on the special form of its race, we may yet comprehend the\ngeneral principles which regulate its first modifications; and,\nremembering the unity of plan so conspicuous throughout nature, we may\n_suspect_ that these principles are in some way concerned in succeeding\nmodifications.\n\n       *       *       *       *       *\n\nA controversy now going on among zoologists, opens yet another field for\nthe application of the deductive method. We believe that the question\nwhether there does or does not exist a _necessary correlation_ among the\nseveral parts of an organism is determinable _a priori_.\n\nCuvier, who first asserted this necessary correlation, professed to base\nhis restorations of extinct animals upon it. Geoffroy St. Hilaire and\nDe Blainville, from different points of view, contested Cuvier's\nhypothesis; and the discussion, which has much interest as bearing on\npaleontology, has been recently revived under a somewhat modified form:\nProfessors Huxley and Owen being respectively the assailant and defender\nof the hypothesis.\n\nCuvier says--\"Comparative anatomy possesses a principle whose just\ndevelopment is sufficient to dissipate all difficulties; it is that of\nthe correlation of forms in organized beings, by means of which every\nkind of organized being might, strictly speaking, be recognized by a\nfragment of any of its parts. Every organized being constitutes a whole,\na single and complete system, whose parts mutually correspond and concur\nby their reciprocal reaction to the same definite end. None of these\nparts can be changed without affecting the others; and consequently each\ntaken separately, indicates and gives all the rest.\" He then gives\nillustrations: arguing that the carnivorous form of tooth necessitating\na certain action of the jaw, implies a particular form in its condyles;\nimplies also limbs fit for seizing and holding prey; therefore implies\nclaws, a certain structure of the leg-bones, a certain form of\nshoulder-blade. Summing up he says, that \"the claw, the scapula, the\ncondyle, the femur, and all the other bones, taken separately, will give\nthe tooth or one another; and by commencing with any one, he who had a\nrational conception of the laws of the organic economy, could\nreconstruct the whole animal.\"\n\nIt will be seen that the method of restoration here contended for, is\nbased on the alleged physiological necessity of the connexion between\nthese several peculiarities. The argument used is, not that a scapula of\na certain shape may be recognized as having belonged to a carnivorous\nmammal because we always find that carnivorous mammals _do_ possess such\nscapulas; but the argument is that they _must_ possess them, because\ncarnivorous habits would be impossible without them. And in the above\nquotation Cuvier asserts that the necessary correlation which he\nconsiders so obvious in these cases, exists throughout the system:\nadmitting, however, that in consequence of our limited knowledge of\nphysiology we are unable in many cases to trace this necessary\ncorrelation, and are obliged to base our conclusions upon observed\ncoexistences, of which we do not understand the reason, but which we\nfind invariable.\n\nNow Professor Huxley has recently shown that, in the first place, this\nempirical method, which Cuvier introduces as quite subordinate, and to\nbe used only in aid of the rational method, is really the method which\nCuvier habitually employed--the so-called rational method remaining\npractically a dead letter; and, in the second place, he has shown that\nCuvier himself has in several places so far admitted the inapplicability\nof the rational method, as virtually to surrender it as a method. But\nmore than this, Professor Huxley contends that the alleged necessary\ncorrelation is not true. Quite admitting the physiological dependence of\nparts on each other, he denies that it is a dependence of a kind which\ncould not be otherwise. \"Thus the teeth of a lion and the stomach of\nthe animal are in such relation that the one is fitted to digest the\nfood which the other can tear, they are physiologically correlated; but\nwe have no reason for affirming this to be a necessary physiological\ncorrelation, in the sense that no other could equally fit its possessor\nfor living on recent flesh. The number and form of the teeth might have\nbeen quite different from that which we know them to be, and the\nconstruction of the stomach might have been greatly altered; and yet the\nfunctions of these organs might have been equally well performed.\"\n\nThus much is needful to give an idea of the controversy. It is not here\nour purpose to go more at length into the evidence cited on either side.\nWe simply wish to show that the question may be settled deductively.\nBefore going on to do this, however, let us briefly notice two\ncollateral points.\n\nIn his defence of the Cuvierian doctrine, Professor Owen avails himself\nof the _odium theologicum_. He attributes to his opponents \"the\ninsinuation and masked advocacy of the doctrine subversive of a\nrecognition of the Higher Mind.\" Now, saying nothing about the\nquestionable propriety of thus prejudging an issue in science, we think\nthis is an unfortunate accusation. What is there in the hypothesis of\n_necessary_, as distinguished from _actual_, correlation of parts, which\nis particularly in harmony with Theism? Maintenance of the _necessity_,\nwhether of sequences or of coexistences, is commonly thought rather a\nderogation from divine power than otherwise. Cuvier says--\"None of these\nparts can be changed without affecting the others; and consequently,\neach taken separately, indicates and gives all the rest.\" That is to\nsay, in the nature of things the correlation _could not_ have been\notherwise. On the other hand, Professor Huxley says we have no warrant\nfor asserting that the correlation _could not_ have been otherwise; but\nhave not a little reason for thinking that the same physiological ends\nmight have been differently achieved. The one doctrine limits the\npossibilities of creation; the other denies the implied limit. Which,\nthen, is most open to the charge of covert Atheism?\n\nOn the other point we lean to the opinion of Professor Owen. We agree\nwith him in thinking that where a rational correlation (in the highest\nsense of the term) can be made out, it affords a better basis for\ndeduction than an empirical correlation ascertained only by accumulated\nobservations. Premising that by rational correlation is not meant one in\nwhich we can trace, or think we can trace, a design, but one of which\nthe negation is inconceivable (and this is the species of correlation\nwhich Cuvier's principle implies); then we hold that our knowledge of\nthe correlation is of a more certain kind than where it is simply\ninductive. We think that Professor Huxley, in his anxiety to avoid the\nerror of making Thought the measure of Things, does not sufficiently\nbear in mind the fact, that as our notion of necessity is determined by\nsome absolute uniformity pervading all orders of our experiences, it\nfollows that an organic correlation which cannot be conceived otherwise,\nis guaranteed by a much wider induction than one ascertained only by the\nobservation of organisms. But the truth is, that there are relatively\nfew organic correlations of which the negation is inconceivable. If we\nfind the skull, vertebrae, ribs, and phalanges of some quadruped as large\nas an elephant; we may indeed be certain that the legs of this quadruped\nwere of considerable size--much larger than those of a rat; and our\nreason for conceiving this correlation as necessary, is, that it is\nbased, not only upon our experiences of moving organisms, but upon all\nour mechanical experiences relative to masses and their supports. But\neven were there many physiological correlations really of this order,\nwhich there are not, there would be danger in pursuing this line of\nreasoning, in consequence of the liability to include within the class\nof truly necessary correlations, those which are not such. For instance,\nthere would seem to be a necessary correlation between the eye and the\nsurface of the body: light being needful for vision, it might be\nsupposed that every eye must be external. Nevertheless it is a fact that\nthere are creatures, as the _Cirrhipedia_, having eyes (not very\nefficient ones, it may be) deeply imbedded within the body. Again, a\nnecessary correlation might be assumed between the dimensions of the\nmammalian uterus and those of the pelvis. It would appear impossible\nthat in any species there should exist a well-developed uterus\ncontaining a full-sized foetus, and yet that the arch of the pelvis\nshould be too small to allow the foetus to pass. And were the only\nmammal having a very small pelvic arch, a fossil one, it would have been\ninferred, on the Cuvierian method, that the foetus must have been born\nin a rudimentary state; and that the uterus must have been\nproportionally small. But there happens to be an extant mammal having an\nundeveloped pelvis--the mole--which presents us with a fact that saves\nus from this erroneous inference. The young of the mole are not born\nthrough the pelvic arch at all; but in front of it! Thus, granting that\nsome quite _direct_ physiological correlations may be necessary, we see\nthat there is great risk of including among them some which are not.\n\nWith regard to the great mass of the correlations, however, including\nall the _indirect_ ones, Professor Huxley seems to us warranted in\ndenying that they are necessary; and we now propose to show deductively\nthe truth of his thesis. Let us begin with an analogy.\n\nWhoever has been through an extensive iron-works, has seen a gigantic\npair of shears worked by machinery, and used for cutting in two, bars of\niron that are from time to time thrust between its blades. Supposing\nthese blades to be the only visible parts of the apparatus, anyone\nobserving their movements (or rather the movement of one, for the other\nis commonly fixed), will see from the manner in which the angle\nincreases and decreases, and from the curve described by the moving\nextremity, that there must be some centre of motion--either a pivot or\nan external box equivalent to it. This may be regarded as a necessary\ncorrelation. Moreover, he might infer that beyond the centre of motion\nthe moving blade was produced into a lever, to which the power was\napplied; but as another arrangement is just possible, this could not be\ncalled anything more than a highly probable correlation. If now he went\na step further, and asked how the reciprocal movement was given to the\nlever, he would perhaps conclude that it was given by a crank. But if he\nknew anything of mechanics, he would know that it might possibly be\ngiven by an eccentric. Or again, he would know that the effect could be\nachieved by a cam. That is to say, he would see that there was no\nnecessary correlation between the shears and the remoter parts of the\napparatus. Take another case. The plate of a printing-press is required\nto move up and down to the extent of an inch or so; and it must exert\nits greatest pressure when it reaches the extreme of its downward\nmovement. If now anyone will look over the stock of a printing-press\nmaker, he will see half a dozen different mechanical arrangements by\nwhich these ends are achieved; and a machinist would tell him that as\nmany more might readily be invented. If, then, there is no necessary\ncorrelation between the special parts of a machine, still less is there\nbetween those of an organism.\n\nFrom a converse point of view the same truth is manifest. Bearing in\nmind the above analogy, it will be foreseen that an alteration in one\npart of an organism will not necessarily entail _some one specific set\nof alterations in the other parts_. Cuvier says, \"None of these parts\ncan be changed without affecting the others; and consequently, each\ntaken separately, indicates and gives all the rest.\" The first of these\npropositions may pass, but the second, which it is alleged follows from\nit, is not true; for it implies that \"all the rest\" can be severally\naffected in only one way and degree, whereas they can be affected in\nmany ways and degrees. To show this, we must again have recourse to a\nmechanical analogy.\n\nIf you set a brick on end and thrust it over, you can predict with\ncertainty in what direction it will fall, and what attitude it will\nassume. If, again setting it up, you put another on the top of it, you\ncan no longer foresee with accuracy the results of an overthrow; and on\nrepeating the experiment, no matter how much care is taken to place the\nbricks in the same positions, and to apply the same degree of force in\nthe same direction, the effects will on no two occasions be exactly\nalike. And in proportion as the aggregation is complicated by the\naddition of new and unlike parts, will the results of any disturbance\nbecome more varied and incalculable. The like truth is curiously\nillustrated by locomotive engines. It is a fact familiar to mechanical\nengineers and engine-drivers, that out of a number of engines built as\naccurately as possible to the same pattern, no two will act in just the\nsame manner. Each will have its peculiarities. The play of actions and\nreactions will so far differ, that under like conditions each will\nbehave in a somewhat different way; and every driver has to learn the\nidiosyncrasies of his own engine before he can work it to the greatest\nadvantage. In organisms themselves this indefiniteness of mechanical\nreaction is clearly traceable. Two boys throwing stones will always\ndiffer more or less in their attitudes, as will two billiard-players.\nThe familiar fact that each individual has a characteristic gait,\nillustrates the point still better. The rhythmical motion of the leg is\nsimple, and on the Cuvierian hypothesis, should react on the body in\nsome uniform way. But in consequence of those slight differences of\nstructure which consist with identity of species, no two individuals\nmake exactly similar movements either of the trunk or the arms. There\nis always a peculiarity recognizable by their friends.\n\nWhen we pass to disturbing forces of a non-mechanical kind, the same\ntruth becomes still more conspicuous. Expose several persons to a\ndrenching storm; and while one will subsequently feel no appreciable\ninconvenience, another will have a cough, another a catarrh, another an\nattack of diarrhoea, another a fit of rheumatism. Vaccinate several\nchildren of the same age with the same quantity of virus, applied to the\nsame part, and the symptoms will not be quite alike in any of them,\neither in kind or intensity; and in some cases the differences will be\nextreme. The quantity of alcohol which will send one man to sleep, will\nrender another unusually brilliant--will make this maudlin, and that\nirritable. Opium will produce either drowsiness or wakefulness: so will\ntobacco.\n\nNow in all these cases--mechanical and other--some force is brought to\nbear primarily on one part of an organism, and secondarily on the rest;\nand, according to the doctrine of Cuvier, the rest ought to be affected\nin a specific way. We find this to be by no means the case. The original\nchange produced in one part does not stand in any necessary correlation\nwith every one of the changes produced in the other parts; nor do these\nstand in any necessary correlation with one another. The functional\nalteration which the disturbing force causes in the organ directly acted\nupon, does not involve some _particular set_ of functional alterations\nin the other organs; but will be followed by some one out of various\nsets. And it is a manifest corollary, that any _structural alteration_\nwhich may eventually be produced in the one organ, will not be\naccompanied by _some particular set of structural alterations_ in the\nother organs. There will be no necessary correlation of forms.\n\nThus Paleontology must depend upon the empirical method. A fossil\nspecies that was obliged to change its food or habits of life, did not\nof necessity undergo the particular set of modifications exhibited; but,\nunder some slight change of predisposing causes--as of season or\nlatitude--might have undergone some other set of modifications: the\ndetermining circumstance being one which, in the human sense, we call\nfortuitous.\n\nMay we not say then, that the deductive method elucidates this vexed\nquestion in physiology; while at the same time our argument collaterally\nexhibits the limits within which the deductive method is applicable. For\nwhile we see that this extremely _general_ question may be\nsatisfactorily dealt with deductively; the conclusion arrived at itself\nimplies that the more _special_ phenomena of organization cannot be so\ndealt with.\n\n       *       *       *       *       *\n\nThere is yet another method of investigating the general truths of\nphysiology--a method to which physiology already owes one luminous idea,\nbut which is not at present formally recognized as a method. We refer to\nthe comparison of physiological phenomena with social phenomena.\n\nThe analogy between individual organisms and the social organism, is one\nthat has from early days occasionally forced itself on the attention of\nthe observant. And though modern science does not countenance those\ncrude ideas of this analogy which have been from time to time expressed\nsince the Greeks flourished; yet it tends to show that there _is_ an\nanalogy, and a remarkable one. While it is becoming clear that there are\nnot those special parallelisms between the constituent parts of a man\nand those of a nation, which have been thought to exist; it is also\nbecoming clear that the general principles of development and structure\ndisplayed in organized bodies are displayed in societies also. The\nfundamental characteristic both of societies and of living creatures,\nis, that they consist of mutually-dependent parts; and it would seem\nthat this involves a community of various other characteristics. Those\nwho are acquainted with the broad facts of both physiology and\nsociology, are beginning to recognize this correspondence not as a\nplausible fancy, but as a scientific truth. And we are strongly of\nopinion that it will by and by be seen to hold to an extent which few at\npresent suspect.\n\nMeanwhile, if any such correspondence exists, it is clear that\nphysiology and sociology will more or less interpret each other. Each\naffords its special facilities for inquiry. Relations of cause and\neffect clearly traceable in the social organism, may lead to the search\nfor analogous ones in the individual organism; and may so elucidate what\nmight else be inexplicable. Laws of growth and function disclosed by the\npure physiologist, may occasionally give us the clue to certain social\nmodifications otherwise difficult to understand. If they can do no more,\nthe two sciences can at least exchange suggestions and confirmations;\nand this will be no small aid. The conception of \"the physiological\ndivision of labour,\" which political economy has already supplied to\nphysiology, is one of no small value. And probably it has others to\ngive.\n\nIn support of this opinion, we will now cite cases in which such aid is\nfurnished. And in the first place, let us see whether the facts of\nsocial organization do not afford additional support to some of the\ndoctrines set forth in the foregoing parts of this article.\n\nOne of the propositions supported by evidence was that in animals the\nprocess of development is carried on, not by differentiations only, but\nby subordinate integrations. Now in the social organism we may see the\nsame duality of process; and further, it is to be observed that the\nintegrations are of the same three kinds. Thus we have integrations\nwhich arise from the simple growth of adjacent parts that perform like\nfunctions: as, for instance, the coalescence of Manchester with its\ncalico-weaving suburbs. We have other integrations which arise when, out\nof several places producing a particular commodity, one monopolizes\nmore and more of the business, and leaves the rest to dwindle: witness\nthe growth of the Yorkshire cloth-districts at the expense of those in\nthe west of England; or the absorption by Staffordshire of the\npottery-manufacture, and the consequent decay of the establishments that\nonce flourished at Worcester, Derby, and elsewhere. And we have those\nyet other integrations which result from the actual approximation of the\nsimilarly-occupied parts: whence result such facts as the concentration\nof publishers in Paternoster Row, of lawyers in the Temple and\nneighbourhood, of corn-merchants about Mark Lane, of civil engineers in\nGreat George Street, of bankers in the centre of the city. Finding thus\nthat in the evolution of the social organism, as in the evolution of\nindividual organisms, there are integrations as well as\ndifferentiations, and moreover that these integrations are of the same\nthree orders; we have additional reason for considering these\nintegrations as essential parts of the developmental process, needed to\nbe included in its formula. And further, the circumstance that in the\nsocial organism these integrations are determined by community of\nfunction, confirms the hypothesis that they are thus determined in the\nindividual organism.\n\nAgain, we endeavoured to show deductively, that the contrasts of parts\nfirst seen in all unfolding embryos, are consequent upon the contrasted\ncircumstances to which such parts are exposed; that thus, adaptation of\nconstitution to conditions is the principle which determines their\nprimary changes; and that, possibly, if we include under the formula\nhereditarily-transmitted adaptations, all subsequent differentiations\nmay be similarly determined. Well, we need not long contemplate the\nfacts to see that some of the predominant social differentiations are\nbrought about in an analogous way. As the members of an\noriginally-homogeneous community multiply and spread, the gradual\nseparation into sections which simultaneously takes place, manifestly\ndepends on differences of local circumstances. Those who happen to\nlive near some place chosen, perhaps for its centrality, as one of\nperiodical assemblage, become traders, and a town springs up; those who\nlive dispersed, continue to hunt or cultivate the earth; those who\nspread to the sea-shore fall into maritime occupations. And each of\nthese classes undergoes modifications of character fitting to its\nfunction. Later in the process of social evolution these local\nadaptations are greatly multiplied. In virtue of differences of soil and\nclimate, the rural inhabitants in different parts of the kingdom, have\ntheir occupations partially specialized; and are respectively\ndistinguished as chiefly producing cattle, or sheep, or wheat, or oats,\nor hops, or cider. People living where coal-fields are discovered become\ncolliers; Cornishmen take to mining because Cornwall is metalliferous;\nand the iron-manufacture is the dominant industry where ironstone is\nplentiful. Liverpool has assumed the office of importing cotton, in\nconsequence of its proximity to the district where cotton goods are\nmade; and for analogous reasons Hull has become the chief port at which\nforeign wools are brought in. Even in the establishment of breweries, of\ndye-works, of slate-quarries, of brick-yards, we may see the same truth.\nSo that, both in general and in detail, these industrial specializations\nof the social organism which characterize separate districts, primarily\ndepend on local circumstances. Of the originally-similar units making up\nthe social mass, different groups assume the different functions which\ntheir respective positions entail; and become adapted to their\nconditions. Thus, that which we concluded, _a priori_, to be the leading\ncause of organic differentiations, we find, _a posteriori_, to be the\nleading cause of social differentiations. Nay further, as we inferred\nthat possibly the embryonic changes which are not thus directly caused,\nare caused by hereditarily-transmitted adaptations; so, we may actually\nsee that in embryonic societies, such changes as are not due to direct\nadaptations, are in the main traceable to adaptations originally\nundergone by the parent society. The colonies founded by distinct\nnations, while they are alike in exhibiting specializations caused in\nthe way above described, grow unlike in so far as they take on, more or\nless, the organizations of the nations they sprung from. A French\nsettlement does not develop exactly after the same manner as an English\none; and both assume forms different from those which Roman settlements\nassumed. Now the fact that the differentiation of societies is\ndetermined partly by the direct adaptation of their units to local\nconditions, and partly by the transmitted influence of like adaptations\nundergone by ancestral societies, tends strongly to enforce the\nconclusion, otherwise reached, that the differentiation of individual\norganisms, similarly results from immediate adaptations compounded with\nancestral adaptations.\n\nFrom confirmations thus furnished by sociology to physiology, let us now\npass to a suggestion similarly furnished. A factory, or other producing\nestablishment, or a town made up of such establishments, is an agency\nfor elaborating some commodity consumed by society at large; and may be\nregarded as analogous to a gland or viscus in an individual organism. If\nwe inquire what is the primitive mode in which one of these producing\nestablishments grows up, we find it to be this. A single worker, who\nhimself sells the produce of his labour, is the germ. His business\nincreasing, he employs helpers--his sons or others; and having done\nthis, he becomes a vendor not only of his own handiwork, but of that of\nothers. A further increase of his business compels him to multiply his\nassistants, and his sale grows so rapid that he is obliged to confine\nhimself to the process of selling: he ceases to be a producer, and\nbecomes simply a channel through which the produce of others is conveyed\nto the public. Should his prosperity rise yet higher, he finds that he\nis unable to manage even the sale of his commodities, and has to employ\nothers, probably of his own family, to aid him in selling; so that, to\nhim as a main channel are now added subordinate channels. Moreover, when\nthere grow up in one place, as a Manchester or a Birmingham, many\nestablishments of like kind, this process is carried still further.\nThere arise factors and buyers, who are the channels through which is\ntransmitted the produce of many factories; and we believe that primarily\nthese factors were manufacturers who undertook to dispose of the produce\nof smaller houses as well as their own, and ultimately became salesmen\nonly. Under a converse aspect, all the stages of this development have\nbeen within these few years exemplified in our railway contractors.\nThere are sundry men now living who illustrate the whole process in\ntheir own persons--men who were originally navvies, digging and\nwheeling; who then undertook some small sub-contract, and worked along\nwith those they paid; who presently took larger contracts, and employed\nforemen; and who now contract for whole railways, and let portions to\nsub-contractors. That is to say, we have men who were originally\nworkers, but have finally become the main channels out of which diverge\nsecondary channels, which again bifurcate into the subordinate channels,\nthrough which flows the money (representing the nutriment) supplied by\nsociety to the actual makers of the railway. Now it seems worth\ninquiring whether this is not the original course followed in the\nevolution of secreting and excreting organs in an animal. We know that\nsuch is the process by which the liver is developed. Out of the group of\nbile-cells forming the germ of it, some centrally-placed ones, lying\nnext to the intestine, are transformed into ducts through which the\nsecretion of the peripheral bile-cells is poured into the intestine; and\nas the peripheral bile-cells multiply, there similarly arise secondary\nducts emptying themselves into the main ones; tertiary ones into these;\nand so on. Recent inquiries show that the like is the case with the\nlungs,--that the bronchial tubes are thus formed. But while analogy\nsuggests that this is the _original_ mode in which such organs are\ndeveloped, it at the same time suggests that this does not necessarily\ncontinue to be the mode. For as we find that in the social organism,\nmanufacturing establishments are no longer commonly developed through\nthe series of modifications above described, but now mostly arise by the\ndirect transformation of a number of persons into master, clerks,\nforemen, workers, &c.; so the approximate method of forming organs, may\nin some cases be replaced by a direct metamorphosis of the organic units\ninto the destined structure, without any transitional structures being\npassed through. That there are organs thus formed is an ascertained\nfact; and the additional question which analogy suggests is, whether the\ndirect method is substituted for the indirect method.\n\nSuch parallelisms might be multiplied. And were it possible here to show\nin detail the close correspondence between the two kinds of\norganization, our case would be seen to have abundant support. But, as\nit is, these few illustrations will sufficiently justify the opinion\nthat study of organized bodies may be indirectly furthered by study of\nthe body politic. Hints may be expected, if nothing more. And thus we\nventure to think that the Inductive Method, usually alone employed by\nmost physiologists, may not only derive important assistance from the\nDeductive Method, but may further be supplemented by the Sociological\nMethod.\n\nFOOTNOTES:\n\n[Footnote 6: Carpenter's _Principles of Comparative Physiology_, pp.\n616-17.]\n\n[Footnote 7: With the exception, perhaps, of the Myxinoid fishes, in\nwhich what is considered as the nasal orifice is single, and on the\nmedian line. But seeing how unusual is the position of this orifice, it\nseems questionable whether it is the true homologue of the nostrils.]\n\n[Footnote 8: In the _Westminster Review_ for April, 1857; and now\nreprinted in this volume.]\n\n[Footnote 9: See Essay on \"Progress: its Law and Cause.\"]\n\n[Footnote 10: This was written before the publication of the _Origin of\nSpecies_. I leave it standing because it shows the stage of thought then\narrived at.]\n\n\n\n\nTHE NEBULAR HYPOTHESIS.\n\n    [_First published in_ The Westminster Review _for July,_ 1858. _In\n    explanation of sundry passages, it seems needful to state that this\n    essay was written in defence of the Nebular Hypothesis at a time\n    when it had fallen into disrepute. Hence there are some opinions\n    spoken of as current which are no longer current._]\n\n\nInquiring into the pedigree of an idea is not a bad means of roughly\nestimating its value. To have come of respectable ancestry, is _prima\nfacie_ evidence of worth in a belief as in a person; while to be\ndescended from a discreditable stock is, in the one case as in the\nother, an unfavourable index. The analogy is not a mere fancy. Beliefs,\ntogether with those who hold them, are modified little by little in\nsuccessive generations; and as the modifications which successive\ngenerations of the holders undergo do not destroy the original type, but\nonly disguise and refine it, so the accompanying alterations of belief,\nhowever much they purify, leave behind the essence of the original\nbelief.\n\nConsidered genealogically, the received theory respecting the creation\nof the Solar System is unmistakably of low origin. You may clearly trace\nit back to primitive mythologies. Its remotest ancestor is the doctrine\nthat the celestial bodies are personages who originally lived on the\nEarth--a doctrine still held by some of the negroes Livingstone visited.\nScience having divested the sun and planets of their divine\npersonalities, this old idea was succeeded by the idea which even Kepler\nentertained, that the planets are guided in their courses by presiding\nspirits: no longer themselves gods, they are still severally kept in\ntheir orbits by gods. And when gravitation came to dispense with these\ncelestial steersmen, there was begotten a belief, less gross than its\nparent, but partaking of the same essential nature, that the planets\nwere originally launched into their orbits by the Creator's hand.\nEvidently, though much refined, the anthropomorphism of the current\nhypothesis is inherited from the aboriginal anthropomorphism, which\ndescribed gods as a stronger order of men.\n\nThere is an antagonist hypothesis which does not propose to honour the\nUnknown Power manifested in the Universe, by such titles as \"The\nMaster-Builder,\" or \"The Great Artificer;\" but which regards this\nUnknown Power as probably working after a method quite different from\nthat of human mechanics. And the genealogy of this hypothesis is as high\nas that of the other is low. It is begotten by that ever-enlarging and\never-strengthening belief in the presence of Law, which accumulated\nexperiences have gradually produced in the human mind. From generation\nto generation Science has been proving uniformities of relation among\nphenomena which were before thought either fortuitous or supernatural in\ntheir origin--has been showing an established order and a constant\ncausation where ignorance had assumed irregularity and arbitrariness.\nEach further discovery of Law has increased the presumption that Law is\neverywhere conformed to. And hence, among other beliefs, has arisen the\nbelief that the Solar System originated, not by _manufacture_ but by\n_evolution_. Besides its abstract parentage in those grand general\nconceptions which Science has generated, this hypothesis has a concrete\nparentage of the highest character. Based as it is on the law of\nuniversal gravitation, it may claim for its remote progenitor the great\nthinker who established that law. It was first suggested by one who\nranks high among philosophers. The man who collected evidence indicating\nthat stars result from the aggregation of diffused matter, was the most\ndiligent, careful, and original astronomical observer of modern times.\nAnd the world has not seen a more learned mathematician than the man\nwho, setting out with this conception of diffused matter concentrating\ntowards its centre of gravity, pointed out the way in which there would\narise, in the course of its concentration, a balanced group of sun,\nplanets, and satellites, like that of which the Earth is a member.\n\nThus, even were there but little direct evidence assignable for the\nNebular Hypothesis, the probability of its truth would be strong. Its\nown high derivation and the low derivation of the antagonist hypothesis,\nwould together form a weighty reason for accepting it--at any rate,\nprovisionally. But the direct evidence assignable for the Nebular\nHypothesis is by no means little. It is far greater in quantity, and\nmore varied in kind, than is commonly supposed. Much has been said here\nand there on this or that class of evidences; but nowhere, so far as we\nknow, have all the evidences been fully stated. We propose here to do\nsomething towards supplying the deficiency: believing that, joined with\nthe _a priori_ reasons given above, the array of _a posteriori_ reasons\nwill leave little doubt in the mind of any candid inquirer.\n\nAnd first, let us address ourselves to those recent discoveries in\nstellar astronomy which have been supposed to conflict with this\ncelebrated speculation.\n\n       *       *       *       *       *\n\nWhen Sir William Herschel, directing his great reflector to various\nnebulous spots, found them resolvable into clusters of stars, he\ninferred, and for a time maintained, that all nebulous spots are\nclusters of stars exceedingly remote from us. But after years of\nconscientious investigation, he concluded that \"there were nebulosities\nwhich are not of a starry nature;\" and on this conclusion was based his\nhypothesis of a diffused luminous fluid which, by its eventual\naggregation, produced stars. A telescopic power much exceeding that used\nby Herschel, has enabled Lord Rosse to resolve some of the nebulae\npreviously unresolved; and, returning to the conclusion which Herschel\nfirst formed on similar grounds but afterwards rejected, many\nastronomers have assumed that, under sufficiently high powers, every\nnebula would be decomposed into stars--that the irresolvability is due\nsolely to distance. The hypothesis now commonly entertained is, that all\nnebulae are galaxies more or less like in nature to that immediately\nsurrounding us; but that they are so inconceivably remote as to look,\nthrough ordinary telescopes, like small faint spots. And not a few have\ndrawn the corollary, that by the discoveries of Lord Rosse the Nebular\nHypothesis has been disproved.\n\nNow, even supposing that these inferences respecting the distances and\nnatures of the nebulae are valid, they leave the Nebular Hypothesis\nsubstantially as it was. Admitting that each of these faint spots is a\nsidereal system, so far removed that its countless stars give less light\nthan one small star of our own sidereal system; the admission is in no\nway inconsistent with the belief that stars, and their attendant\nplanets, have been formed by the aggregation of nebulous matter. Though,\ndoubtless, if the existence of nebulous matter now in course of\nconcentration be disproved, one of the evidences of the Nebular\nHypothesis is destroyed, yet the remaining evidences remain. It is a\ntenable position that though nebular condensation is now nowhere to be\nseen in progress, yet it was once going on universally. And, indeed, it\nmight be argued that the still-continued existence of diffused nebulous\nmatter is scarcely to be expected; seeing that the causes which have\nresulted in the aggregation of one mass, must have been acting on all\nmasses, and that hence the existence of masses not aggregated would be a\nfact calling for explanation. Thus, granting the immediate conclusions\nsuggested by these recent disclosures of the six-feet reflector, the\ncorollary which many have drawn is inadmissible.\n\nBut these conclusions may be successfully contested. Receiving them\nthough we have been, for years past, as established truths, a critical\nexamination of the facts has convinced us that they are quite\nunwarrantable. They involve so many manifest incongruities, that we have\nbeen astonished to find men of science entertaining them, even as\nprobable. Let us consider these incongruities.\n\n       *       *       *       *       *\n\nIn the first place, mark what is inferable from the distribution of\nnebulae.\n\n     \"The spaces which precede or which follow simple nebulae,\" says\n     Arago, \"and _a fortiori_, groups of nebulae, contain generally few\n     stars. Herschel found this rule to be invariable. Thus every time\n     that during a short interval no star approached in virtue of the\n     diurnal motion, to place itself in the field of his motionless\n     telescope, he was accustomed to say to the secretary who assisted\n     him,--'Prepare to write; nebulae are about to arrive.'\"\n\nHow does this fact consist with the hypothesis that nebulae are remote\ngalaxies? If there were but one nebula, it would be a curious\ncoincidence were this one nebula so placed in the distant regions of\nspace, as to agree in direction with a starless spot in our own sidereal\nsystem. If there were but two nebulae, and both were so placed, the\ncoincidence would be excessively strange. What, then, shall we say on\nfinding that there are thousands of nebulae so placed? Shall we believe\nthat in thousands of cases these far-removed galaxies happen to agree in\ntheir visible positions with the thin places in our own galaxy? Such a\nbelief is impossible.\n\nStill more manifest does the impossibility of it become when we consider\nthe general distribution of nebulae. Besides again showing itself in the\nfact that \"the poorest regions in stars are near the richest in nebulae,\"\nthe law above specified applies to the heavens as a whole. In that zone\nof celestial space where stars are excessively abundant, nebulae are\nrare; while in the two opposite celestial spaces that are furthest\nremoved from this zone, nebulae are abundant. Scarcely any nebulae lie\nnear the galactic circle (or plane of the Milky Way); and the great\nmass of them lie round the galactic poles. Can this also be mere\ncoincidence? When to the fact that the general mass of nebulae are\nantithetical in position to the general mass of stars, we add the fact\nthat local regions of nebulae are regions where stars are scarce, and the\nfurther fact that single nebulae are habitually found in comparatively\nstarless spots; does not the proof of a physical connexion become\noverwhelming? Should it not require an infinity of evidence to show that\nnebulae are not parts of our sidereal system? Let us see whether any such\ninfinity of evidence is assignable. Let us see whether there is even a\nsingle alleged proof which will bear examination.\n\n     \"As seen through colossal telescopes,\" says Humboldt, \"the\n     contemplation of these nebulous masses leads us into regions from\n     whence a ray of light, according to an assumption not wholly\n     improbable, requires millions of years to reach our earth--to\n     distances for whose measurement the dimensions (the distance of\n     Sirius, or the calculated distances of the binary stars in Cygnus\n     and the Centaur) of our nearest stratum of fixed stars scarcely\n     suffice.\"\n\nIn this confused sentence there is implied a belief, that the distances\nof the nebulae from our galaxy of stars as much transcend the distances\nof our stars from one another, as these interstellar distances transcend\nthe dimensions of our planetary system. Just as the diameter of the\nEarth's orbit, is a mere point when compared with the distance of our\nSun from Sirius; so is the distance of our Sun from Sirius, a mere point\nwhen compared with the distance of our galaxy from those far-removed\ngalaxies constituting nebulae. Observe the consequences of this\nassumption.\n\nIf one of these supposed galaxies is so remote that its distance dwarfs\nour interstellar spaces into points, and therefore makes the dimensions\nof our whole sidereal system relatively insignificant; does it not\ninevitably follow that the telescopic power required to resolve this\nremote galaxy into stars, must be incomparably greater than the\ntelescopic power required to resolve the whole of our own galaxy into\nstars? Is it not certain that an instrument which can just exhibit with\nclearness the most distant stars of our own cluster, must be utterly\nunable to separate one of these remote clusters into stars? What, then,\nare we to think when we find that the same instrument which decomposes\nhosts of nebulae into stars, _fails_ to resolve completely our own Milky\nWay? Take a homely comparison. Suppose a man who was surrounded by a\nswarm of bees, extending, as they sometimes do, so high in the air as to\nrender some of the individual bees almost invisible, were to declare\nthat a certain spot on the horizon was a swarm of bees; and that he knew\nit because he could see the bees as separate specks. Incredible as the\nassertion would be, it would not exceed in incredibility this which we\nare criticising. Reduce the dimensions to figures, and the absurdity\nbecomes still more palpable. In round numbers, the distance of Sirius\nfrom the Earth is half a million times the distance of the Earth from\nthe Sun; and, according to the hypothesis, the distance of a nebula is\nsomething like half a million times the distance of Sirius. Now, our own\n\"starry island, or nebula,\" as Humboldt calls it, \"forms a lens-shaped,\nflattened, and everywhere detached stratum, whose major axis is\nestimated at seven or eight hundred, and its minor axis at a hundred and\nfifty times the distance of Sirius from the Earth.\"[11] And since it is\nconcluded that the Solar System is near the centre of this aggregation,\nit follows that our distance from the remotest parts of it is some four\nhundred distances of Sirius. But the stars forming these remotest parts\nare not individually visible, even through telescopes of the highest\npower. How, then, can such telescopes make individually visible the\nstars of a nebula which is half a million times the distance of Sirius?\nThe implication is, that a star rendered invisible by distance becomes\nvisible if taken twelve hundred times further off! Shall we accept this\nimplication? or shall we not rather conclude that the nebulae are _not_\nremote galaxies? Shall we not infer that, be their nature what it may,\nthey must be at least as near to us as the extremities of our own\nsidereal system?\n\nThroughout the above argument, it is tacitly assumed that differences of\napparent magnitude among the stars, result mainly from differences of\ndistance. On this assumption the current doctrines respecting the nebulae\nare founded; and this assumption is, for the nonce, admitted in each of\nthe foregoing criticisms. From the time, however, when it was first made\nby Sir W. Herschel, this assumption has been purely gratuitous; and it\nnow proves to be inadmissible. But, awkwardly enough, its truth and its\nuntruth are alike fatal to the conclusions of those who argue after the\nmanner of Humboldt. Note the alternatives.\n\nOn the one hand, what follows from the untruth of the assumption? If\napparent largeness of stars is not due to comparative nearness, and\ntheir successively smaller sizes to their greater and greater degrees of\nremoteness, what becomes of the inferences respecting the dimensions of\nour sidereal system and the distances of nebulae? If, as has lately been\nshown, the almost invisible star 61 Cygni has a greater parallax than\n[Greek: a] Cygni, though, according to an estimate based on Sir W.\nHerschel's assumption, it should be about twelve times more distant--if,\nas it turns out, there exist telescopic stars which are nearer to us\nthan Sirius; of what worth is the conclusion that the nebulae are very\nremote, because their component luminous masses are made visible only by\nhigh telescopic powers? Clearly, if the most brilliant star in the\nheavens and a star that cannot be seen by the naked eye, prove to be\nequidistant, relative distances cannot be in the least inferred from\nrelative visibilities. And if so, nebulae may be comparatively near,\nthough the starlets of which they are made up appear extremely minute.\n\nOn the other hand, what follows if the truth of the assumption be\ngranted? The arguments used to justify this assumption in the case of\nthe stars, equally justify it in the case of the nebulae. It cannot be\ncontended that, on the average, the _apparent_ sizes of the stars\nindicate their distances, without its being admitted that, on the\naverage, the _apparent_ sizes of the nebulae indicate their\ndistances--that, generally speaking, the larger are the nearer and the\nsmaller are the more distant. Mark, now, the necessary inference\nrespecting their resolvability. The largest or nearest nebulae will be\nmost easily resolved into stars; the successively smaller will be\nsuccessively more difficult of resolution; and the irresolvable ones\nwill be the smallest ones. This, however, is exactly the reverse of the\nfact. The largest nebulae are either wholly irresolvable, or but\npartially resolvable under the highest telescopic powers; while large\nnumbers of quite small nebulae are easily resolved by far less powerful\ntelescopes. An instrument through which the great nebula in Andromeda,\ntwo and a half degrees long and one degree broad, appears merely as a\ndiffused light, decomposes a nebula of fifteen minutes diameter into\ntwenty thousand starry points. At the same time that the individual\nstars of a nebula eight minutes in diameter are so clearly seen as to\nallow of their number being estimated, a nebula covering an area five\nhundred times as great shows no stars at all! What possible explanation\nof this can be given on the current hypothesis?\n\nYet a further difficulty remains--one which is, perhaps, still more\nobviously fatal than the foregoing. This difficulty is presented by the\nphenomena of the Magellanic clouds. Describing the larger of these, Sir\nJohn Herschel says:--\n\n     \"The Nubecula Major, like the Minor, consists partly of large\n     tracts and ill-defined patches of irresolvable nebula, and of\n     nebulosity in every stage of resolution, up to perfectly resolved\n     stars like the Milky Way, as also of regular and irregular nebulae\n     properly so called, of globular clusters in every stage of\n     resolvability, and of clustering groups sufficiently insulated and\n     condensed to come under the designation of 'clusters of\n     stars.'\"--_Cape Observations_, p. 146.\n\nIn his _Outlines of Astronomy_, Sir John Herschel, after repeating this\ndescription in other words, goes on to remark that--\n\n     \"This combination of characters, rightly considered, is in a high\n     degree instructive, affording an insight into the probable\n     comparative distance of _stars_ and _nebulae_, and the real\n     brightness of individual stars as compared with one another. Taking\n     the apparent semidiameter of the nubecula major at three degrees,\n     and regarding its solid form as, roughly speaking, spherical, its\n     nearest and most remote parts differ in their distance from us by a\n     little more than a tenth part of our distance from its center. The\n     brightness of objects situated in its nearer portions, therefore,\n     cannot be _much_ exaggerated, nor that of its remoter _much_\n     enfeebled, by their difference of distance; yet within this\n     globular space, we have collected upwards of six hundred stars of\n     the seventh, eighth, ninth, and tenth magnitudes, nearly three\n     hundred nebulae, and globular and other clusters, _of all degrees of\n     resolvability_, and smaller scattered stars innumerable of every\n     inferior magnitude, from the tenth to such as by their multitude\n     and minuteness constitute irresolvable nebulosity, extending over\n     tracts of many square degrees. Were there but one such object, it\n     might be maintained without utter improbability that its apparent\n     sphericity is only an effect of foreshortening, and that in reality\n     a much greater proportional difference of distance between its\n     nearer and more remote parts exists. But such an adjustment,\n     improbable enough in one case, must be rejected as too much so for\n     fair argument in two. It must, therefore, be taken as a\n     demonstrated fact, that stars of the seventh or eighth magnitude\n     and irresolvable nebula may co-exist within limits of distance not\n     differing in proportion more than as nine to ten.\"--_Outlines of\n     Astronomy_ (10th Ed.), pp. 656-57.\n\nThis supplies yet another _reductio ad absurdum_ of the doctrine we are\ncombating. It gives us the choice of two incredibilities. If we are to\nbelieve that one of these included nebulae is so remote that its hundred\nthousand stars look like a milky spot, invisible to the naked eye; we\nmust also believe that there are single stars so enormous that though\nremoved to this same distance they remain visible. If we accept the\nother alternative, and say that many nebulae are no further off than our\nown stars of the eighth magnitude; then it is requisite to say that at\na distance not greater than that at which a single star is still\nfaintly visible to the naked eye, there may exist a group of a hundred\nthousand stars which is invisible to the naked eye. Neither of these\nsuppositions can be entertained. What, then, is the conclusion that\nremains? This only:--that the nebulae are not further from us than parts\nof our own sidereal system, of which they must be considered members;\nand that when they are resolvable into discrete masses, these masses\ncannot be considered as stars in anything like the ordinary sense of\nthat word.[12]\n\nAnd now, having seen the untenability of this idea, rashly espoused by\nsundry astronomers, that the nebulae are extremely remote galaxies; let\nus consider whether the various appearances they present are not\nreconcilable with the Nebular Hypothesis.\n\n       *       *       *       *       *\n\nGiven a rare and widely-diffused mass of nebulous matter, having a\ndiameter, say, of one hundred times that of the Solar System,[13] what\nare the successive changes that may be expected to take place in it?\nMutual gravitation will approximate its atoms or its molecules; but\ntheir approximation will be opposed by that atomic motion the resultant\nof which we recognize as repulsion, and the overcoming of which implies\nthe evolution of heat. As fast as this heat partially escapes by\nradiation, further approximation will take place, attended by further\nevolution of heat, and so on continuously: the processes not occurring\nseparately as here described, but simultaneously, uninterruptedly, and\nwith increasing activity. When the nebulous mass has reached a\nparticular stage of condensation--when its internally-situated atoms\nhave approached to within certain distances, have generated a certain\namount of heat, and are subject to a certain mutual pressure,\ncombinations may be anticipated. Whether the molecules produced be of\nkinds such as we know, which is possible, or whether they be of kinds\nsimpler than any we know, which is more probable, matters not to the\nargument. It suffices that molecular unions, either between atoms of the\nsame kind or between atoms of different kinds, will finally take place.\nWhen they do take place, they will be accompanied by a sudden and great\ndisengagement of heat; and until this excess of heat has escaped, the\nnewly-formed molecules will remain uniformly diffused, or, as it were,\ndissolved in the pre-existing nebulous medium.\n\nBut now what may be expected by and by to happen? When radiation has\nadequately lowered the temperature, these molecules will precipitate;\nand, having precipitated, they will not remain uniformly diffused, but\nwill aggregate into flocculi; just as water, precipitated from air,\ncollects into clouds. Concluding, thus, that a nebulous mass will, in\ncourse of time, resolve itself into flocculi of precipitated denser\nmatter, floating in the rarer medium from which they were precipitated,\nlet us inquire what are the mechanical results to be inferred. Of\nclustered bodies in empty space, each will move along a line which is\nthe resultant of the tractive forces exercised by all the rest, modified\nfrom moment to moment by the acquired motion; and the aggregation of\nsuch clustered bodies, if it eventually results at all, can result only\nfrom collision, dissipation, and the formation of a resisting medium.\nBut with clustered bodies already immersed in a resisting medium, and\nespecially if such bodies are of small densities, such as those we are\nconsidering, the process of concentration will begin forthwith: two\nfactors conspiring to produce it. The flocculi described, irregular in\ntheir shapes and presenting, as they must in nearly all cases,\nunsymmetrical faces to their lines of motion, will be deflected from\nthose courses which mutual gravitation, if uninterfered with, would\nproduce among them; and this will militate against that balancing of\nmovements which permanence of the cluster pre-supposes. If it be said,\nas it may truly be said, that this is too trifling a cause of\nderangement to produce much effect, then there comes the more important\ncause with which it co-operates. The medium from which the flocculi have\nbeen precipitated, and through which they are moving, must, by\ngravitation, be rendered denser in its central parts than in its\nperipheral parts. Hence the flocculi, none of them moving in straight\nlines to the common centre of gravity, but having courses made to\ndiverge to one or other side of it (in small degrees by the cause just\nassigned, and in much greater degrees by the tractive forces of other\nflocculi) will, in moving towards the central region, meet with greater\nresistances on their inner sides than on their outer sides; and will be\nthus made to diverge outwardly from their courses more than they would\notherwise do. Hence a tendency which, apart from other tendencies, will\ncause them severally to go on one or other side of the centre of\ngravity, and, approaching it, to get motions more and more tangential.\nObserve, however, that their respective motions will be deflected, not\ntowards one side of the common centre of gravity, but towards various\nsides. How then can there result a movement common to them all? Very\nsimply. Each flocculus, in describing its course, must give motion to\nthe medium through which it is moving. But the probabilities are\ninfinity to one against all the respective motions thus impressed on\nthis medium, exactly balancing one another. And if they do not balance\none another the result must be rotation of the whole mass of the medium\nin one direction. But preponderating momentum in one direction, having\ncaused rotation of the medium in that direction, the rotating medium\nmust in its turn gradually arrest such flocculi as are moving in\nopposition, and impress its own motion upon them; and thus there will\nultimately be formed a rotating medium with suspended flocculi partaking\nof its motion, while they move in converging spirals towards the common\ncentre of gravity.[14]\n\nBefore comparing these conclusions with facts, let us pursue the\nreasoning a little further, and observe certain subordinate actions. The\nrespective flocculi must be drawn not towards their common centre of\ngravity only, but also towards neighbouring flocculi. Hence the whole\nassemblage of flocculi will break up into groups: each group\nconcentrating towards its local centre of gravity, and in so doing\nacquiring a vortical movement like that subsequently acquired by the\nwhole nebula. According to circumstances, and chiefly according to the\nsize of the original nebulous mass, this process of local aggregation\nwill produce various results. If the whole nebula is but small, the\nlocal groups of flocculi may be drawn into the common centre of gravity\nbefore their constituent masses have coalesced with one another. In a\nlarger nebula, these local aggregations may have concentrated into\nrotating spheroids of vapour, while yet they have made but little\napproach towards the general focus of the system. In a still larger\nnebula, where the local aggregations are both greater and more remote\nfrom the common centre of gravity, they may have condensed into masses\nof molten matter before the general distribution of them has greatly\naltered. In short, as the conditions in each case determine, the\ndiscrete masses produced may vary indefinitely in number, in size, in\ndensity, in motion, in distribution.\n\nAnd now let us return to the visible characters of nebulae, as observed\nthrough modern telescopes. Take first the description of those nebulae\nwhich, by the hypothesis, must be in an early stage of evolution.\n\n     Among the \"_irregular nebulae_,\" says Sir John Herschel, \"may be\n     comprehended all which, to _a want of complete and in most\n     instances even of partial resolvability_ by the power of the\n     20-feet reflector, unite such a deviation from the circular or\n     elliptic form, or such a want of symmetry (with that form) as\n     preclude their being placed in class 1, or that of Regular Nebulae.\n     This second class comprises many of the most remarkable and\n     interesting objects in the heavens, _as well as the most extensive\n     in respect of the area they occupy_.\"\n\nAnd, referring to this same order of objects, M. Arago says:--\"The forms\nof very large diffuse nebulae do not appear to admit of definition; they\nhave no regular outline.\"\n\nThis coexistence of largeness, irregularity, and indefiniteness of\noutline, with irresolvability, is extremely significant. The fact that\nthe largest nebulae are either irresolvable or very difficult to resolve,\nmight have been inferred _a priori_; seeing that irresolvability,\nimplying that the aggregation of precipitated matter has gone on to but\na small extent, will be found in nebulae of wide diffusion. Again, the\nirregularity of these large, irresolvable nebulae, might also have been\nexpected; seeing that their outlines, compared by Arago with \"the\nfantastic figures which characterize clouds carried away and tossed\nabout by violent and often contrary winds,\" are similarly characteristic\nof a mass not yet gathered together by the mutual attraction of its\nparts. And once more, the fact that these large, irregular, irresolvable\nnebulae have indefinite outlines--outlines that fade off insensibly into\nsurrounding darkness--is one of like meaning.\n\nSpeaking generally (and of course differences of distance negative\nanything beyond average statements), the spiral nebulae are smaller than\nthe irregular nebulae, and more resolvable; at the same time that they\nare not so small as the regular nebulae, and not so resolvable. This is\nas, according to the hypothesis, it should be. The degree of\ncondensation causing spiral movement, is a degree of condensation also\nimplying masses of flocculi that are larger, and therefore more visible,\nthan those existing in an earlier stage. Moreover, the forms of these\nspiral nebulae are quite in harmony with the explanation given. The\ncurves of luminous matter which they exhibit, are _not_ such as would be\ndescribed by discrete masses starting from a state of rest, and moving\nthrough a resisting medium to a common centre of gravity; but they _are_\nsuch as would be described by masses having their movements modified by\nthe rotation of the medium.\n\nIn the centre of a spiral nebula is seen a mass both more luminous and\nmore resolvable than the rest. Assume that, in process of time, all the\nspiral streaks of luminous matter which converge to this centre are\ndrawn into it, as they must be; assume further, that the flocculi, or\nother discrete portions constituting these luminous streaks, aggregate\ninto larger masses at the same time that they approach the central\ngroup, and that the masses forming this central group also aggregate\ninto larger masses; and there will finally result a cluster of such\nlarger masses, which will be resolvable with comparative ease. And, as\nthe coalescence and concentration go on, the constituent masses will\ngradually become fewer, larger, brighter, and more densely collected\naround the common centre of gravity. See now how completely this\ninference agrees with observation. \"The circular form is that which most\ncommonly characterises resolvable nebulae,\" writes Arago. Resolvable\nnebulae, says Sir John Herschel, \"are almost universally round or oval.\"\nMoreover, the centre of each group habitually displays a closer\nclustering of the constituent masses than the outer parts; and it is\nshown that, under the law of gravitation, which we now know extends to\nthe stars, this distribution is _not_ one of equilibrium, but implies\nprogressing concentration. While, just as we inferred that, according to\ncircumstances, the extent to which aggregation has been carried must\nvary; so we find that, in fact, there are regular nebulae of all degrees\nof resolvability, from those consisting of innumerable minute masses, to\nthose in which their numbers are smaller and the sizes greater, and to\nthose in which there are a few large bodies worthy to be called stars.\n\nOn the one hand, then, we see that the notion, of late years\nuncritically received, that the nebulae are extremely remote galaxies of\nstars like those which make up our own Milky Way, is totally\nirreconcilable with the facts--involves us in sundry absurdities. On the\nother hand, we see that the hypothesis of nebular condensation\nharmonizes with the most recent results of stellar astronomy: nay\nmore--that it supplies us with an explanation of various appearances\nwhich in its absence would be incomprehensible.\n\n       *       *       *       *       *\n\nDescending now to the Solar System, let us consider first a class of\nphenomena in some sort transitional--those offered by comets. In them,\nor at least in those most numerous of them which lie far out of the\nplane of the Solar System, and are not to be counted among its members,\nwe have, still existing, a kind of matter like that out of which,\naccording to the Nebular Hypothesis, the Solar System was evolved.\nHence, for the explanation of them, we must go back to the time when the\nsubstances forming the sun and planets were yet unconcentrated.\n\nWhen diffused matter, precipitated from a rarer medium, is aggregating,\nthere are certain to be here and there produced small flocculi, which\nlong remain detached; as do, for instance, minute shreds of cloud in a\nsummer sky. In a concentrating nebula these will, in the majority of\ncases, eventually coalesce with the larger flocculi near to them. But it\nis tolerably evident that some of those formed at the outermost parts of\nthe nebula, will _not_ coalesce with the larger internal masses, but\nwill slowly follow without overtaking them. The relatively greater\nresistance of the medium necessitates this. As a single feather falling\nto the ground will be rapidly left behind by a pillow-full of feathers;\nso, in their progress to the common centre of gravity, will the\noutermost shreds of vapour be left behind by the great masses of vapour\ninternally situated. But we are not dependent merely on reasoning for\nthis belief. Observation shows us that the less concentrated external\nparts of nebulae, _are_ left behind by the more concentrated internal\nparts. Examined through high powers, all nebulae, even when they have\nassumed regular forms, are seen to be surrounded by luminous streaks, of\nwhich the directions show that they are being drawn into the general\nmass. Still higher powers bring into view still smaller, fainter, and\nmore widely-dispersed streaks. And it cannot be doubted that the minute\nfragments which no telescopic aid makes visible, are yet more numerous\nand widely dispersed. Thus far, then, inference and observation are at\none.\n\nGranting that the great majority of these outlying portions of nebulous\nmatter will be drawn into the central mass long before it reaches a\ndefinite form, the presumption is that some of the very small,\nfar-removed portions will not be so; but that before they arrive near\nit, the central mass will have contracted into a comparatively moderate\nbulk. What now will be the characters of these late-arriving portions?\n\nIn the first place, they will have either extremely eccentric orbits or\nnon-elliptic paths. Left behind at a time when they were moving towards\nthe centre of gravity in slightly-deflected lines, and therefore having\nbut very small angular velocities, they will approach the central mass\nin greatly elongated curves; and rushing round it, will go off again\ninto space. That is, they will behave just as we see the majority of\ncomets do; the orbits of which are either so eccentric as to be\nindistinguishable from parabolas, or else are not orbits at all, but are\npaths which are distinctly either parabolic or hyperbolic.\n\nIn the second place, they will come from all parts of the heavens. Our\nsupposition implies that they were left behind at a time when the\nnebulous mass was of irregular shape, and had not acquired a definite\nrotation; and as the separation of them would not be from any one\nsurface of the nebulous mass more than another, the conclusion must be\nthat they will come to the central body from various directions in\nspace. This, too, is exactly what happens. Unlike planets, whose orbits\napproximate to one plane, comets have orbits that show no relation to\none another; but cut the plane of the ecliptic at all angles, and have\naxes inclined to it at all angles.\n\nIn the third place, these remotest flocculi of nebulous matter will, at\nthe outset, be deflected from their direct courses to the common centre\nof gravity, not all on one side, but each on such side as its form, or\nits original proper motion, determines. And being left behind before the\nrotation of the nebula is set up, they will severally retain their\ndifferent individual motions. Hence, following the concentrated mass,\nthey will eventually go round it on all sides; and as often from right\nto left as from left to right. Here again the inference perfectly\ncorresponds with the facts. While all the planets go round the sun from\nwest to east, comets as often go round the sun from east to west as from\nwest to east. Of 262 comets recorded since 1680, 130 are direct, and 132\nare retrograde. This equality is what the law of probabilities would\nindicate.\n\nThen, in the fourth place, the physical constitution of comets accords\nwith the hypothesis.[15] The ability of nebulous matter to concentrate\ninto a concrete form, depends on its mass. To bring its ultimate atoms\ninto that proximity requisite for chemical union--requisite, that is,\nfor the production of denser matter--their repulsion must be overcome.\nThe only force antagonistic to their repulsion, is their mutual\ngravitation. That their mutual gravitation may generate a pressure and\ntemperature of sufficient intensity, there must be an enormous\naccumulation of them; and even then the approximation can slowly go on\nonly as fast as the evolved heat escapes. But where the quantity of\natoms is small, and therefore the force of mutual gravitation small,\nthere will be nothing to coerce the atoms into union. Whence we infer\nthat these detached fragments of nebulous matter will continue in\ntheir original state. Non-periodic comets seem to do so.\n\nWe have already seen that this view of the origin of comets harmonizes\nwith the characters of their orbits; but the evidence hence derived is\nmuch stronger than was indicated. The great majority of cometary orbits\nare classed as parabolic; and it is ordinarily inferred that they are\nvisitors from remote space, and will never return. But are they rightly\nclassed as parabolic? Observations on a comet moving in an extremely\neccentric ellipse, which are possible only when it is comparatively near\nperihelion, must fail to distinguish its orbit from a parabola.\nEvidently, then, it is not safe to class it as a parabola because of\ninability to detect the elements of an ellipse. But if extreme\neccentricity of an orbit necessitates such inability, it seems quite\npossible that comets have no other orbits than elliptic ones. Though\nfive or six are said to be hyperbolic, yet, as I learn from one who has\npaid special attention to comets, \"no such orbit has, I believe, been\ncomputed for a well-observed comet.\" Hence the probability that all the\norbits are ellipses is overwhelming. Ellipses and hyperbolas have\ncountless varieties of forms, but there is only one form of parabola;\nor, to speak literally, all parabolas are similar, while there are\ninfinitely numerous dissimilar ellipses and dissimilar hyperbolas.\nConsequently, anything coming to the Sun from a great distance must have\none exact amount of proper motion to produce a parabola: all other\namounts would give hyperbolas or ellipses. And if there are no\nhyperbolic orbits, then it is infinity to one that all the orbits are\nelliptical. This is just what they would be if comets had the genesis\nabove supposed.\n\n       *       *       *       *       *\n\nAnd now, leaving these erratic bodies, let us turn to the more familiar\nand important members of the Solar System. It was the remarkable harmony\namong their movements which first made Laplace conceive that the Sun,\nplanets, and satellites had resulted from a common genetic process. As\nSir William Herschel, by his observations on the nebulae, was led to the\nconclusion that stars resulted from the aggregation of diffused matter;\nso Laplace, by his observations on the structure of the Solar System,\nwas led to the conclusion that only by the rotation of aggregating\nmatter were its peculiarities to be explained. In his _Exposition du\nSysteme du Monde_, he enumerates as the leading evidences:--1. The\nmovements of the planets in the same direction and in orbits approaching\nto the same plane; 2. The movements of the satellites in the same\ndirection as those of the planets; 3. The movements of rotation of these\nvarious bodies and of the sun in the same direction as the orbital\nmotions, and mostly in planes little different; 4. The small\neccentricities of the orbits of the planets and satellites, as\ncontrasted with the great eccentricities of the cometary orbits. And the\nprobability that these harmonious movements had a common cause, he\ncalculates as two hundred thousand billions to one.\n\nThis immense preponderance of probability does not point to a common\ncause under the form ordinarily conceived--an Invisible Power working\nafter the method of \"a Great Artificer;\" but to an Invisible Power\nworking after the method of evolution. For though the supporters of the\ncommon hypothesis may argue that it was necessary for the sake of\nstability that the planets should go round the Sun in the same direction\nand nearly in one plane, they cannot thus account for the direction of\nthe axial motions.[16] The mechanical equilibrium would not have been\ninterfered with, had the Sun been without any rotatory movement; or had\nhe revolved on his axis in a direction opposite to that in which the\nplanets go round him; or in a direction at right angles to the average\nplane of their orbits. With equal safety the motion of the Moon round\nthe Earth might have been the reverse of the Earth's motion round its\naxis; or the motions of Jupiter's satellites might similarly have been\nat variance with his axial motion; or those of Saturn's satellites with\nhis. As, however, none of these alternatives have been followed, the\nuniformity must be considered, in this case as in all others, evidence\nof subordination to some general law--implies what we call natural\ncausation, as distinguished from arbitrary arrangement.\n\nHence the hypothesis of evolution would be the only probable one, even\nin the absence of any clue to the particular mode of evolution. But when\nwe have, propounded by a mathematician of the highest authority, a\ntheory of this evolution based on established mechanical principles,\nwhich accounts for these various peculiarities, as well as for many\nminor ones, the conclusion that the Solar System _was_ evolved becomes\nalmost irresistible.\n\nThe general nature of Laplace's theory scarcely needs stating. Books of\npopular astronomy have familiarized most readers with his\nconceptions;--namely, that the matter now condensed into the Solar\nSystem, once formed a vast rotating spheroid of extreme rarity extending\nbeyond the orbit of the outermost planet; that as this spheroid\ncontracted, its rate of rotation necessarily increased; that by\naugmenting centrifugal force its equatorial zone was from time to time\nprevented from following any further the concentrating mass, and so\nremained behind as a revolving ring; that each of the revolving rings\nthus periodically detached, eventually became ruptured at its weakest\npoint, and, contracting on itself, gradually aggregated into a rotating\nmass; that this, like the parent mass, increased in rapidity of rotation\nas it decreased in size, and, where the centrifugal force was\nsufficient, similarly left behind rings, which finally collapsed into\nrotating spheroids; and that thus, out of these primary and secondary\nrings, there arose planets and their satellites, while from the central\nmass there resulted the Sun. Moreover, it is tolerably well known that\nthis _a priori_ reasoning harmonizes with the results of experiment. Dr.\nPlateau has shown that when a mass of fluid is, as far may be, protected\nfrom the action of external forces, it will, if made to rotate with\nadequate velocity, form detached rings; and that these rings will break\nup into spheroids which turn on their axes in the same direction with\nthe central mass. Thus, given the original nebula, which, acquiring a\nvortical motion in the way indicated, has at length concentrated into a\nvast spheroid of aeriform matter moving round its axis--given this, and\nmechanical principles explain the rest. The genesis of a Solar System\ndisplaying movements like those observed, may be predicted; and the\nreasoning on which the prediction is based is countenanced by\nexperiment.[17]\n\nBut now let us inquire whether, besides these most conspicuous\nstructural and dynamic peculiarities of the Solar System, sundry minor\nones are not similarly explicable.\n\n       *       *       *       *       *\n\nTake first the relation between the planes of the planetary orbits and\nthe plane of the Sun's equator. If, when the nebulous spheroid extended\nbeyond the orbit of Neptune, all parts of it had been revolving exactly\nin the same plane, or rather in parallel planes--if all its parts had\nhad one axis; then the planes of the successive rings would have been\ncoincident with each other and with that of the Sun's rotation. But it\nneeds only to go back to the earlier stages of concentration, to see\nthat there could exist no such complete uniformity of motion. The\nflocculi, already described as precipitated from an irregular and\nwidely-diffused nebula, and as starting from all points to their common\ncentre of gravity, must move not in one plane but in innumerable planes,\ncutting each other at all angles. The gradual establishment of a\nvortical motion such as we at present see indicated in the spiral\nnebulae, is the gradual approach towards motion in one plane. But this\nplane can but slowly become decided. Flocculi not moving in this plane,\nbut entering into the aggregation at various inclinations, will tend to\nperform their revolutions round its centre in their own planes; and only\nin course of time will their motions be partly destroyed by conflicting\nones, and partly resolved into the general motion. Especially will the\noutermost portions of the rotating mass retain for a long time their\nmore or less independent directions. Hence the probabilities are, that\nthe planes of the rings first detached will differ considerably from the\naverage plane of the mass; while the planes of those detached latest\nwill differ from it less.\n\nHere, again, inference to a considerable extent agrees with observation.\nThough the progression is irregular, yet, on the average, the\ninclinations decrease on approaching the Sun; and this is all we can\nexpect. For as the portions of the nebulous spheroid must have arrived\nwith miscellaneous inclinations, its strata must have had planes of\nrotation diverging from the average plane in degrees not always\nproportionate to their distances from the centre.\n\n       *       *       *       *       *\n\nConsider next the movements of the planets on their axes. Laplace\nalleged as one among other evidences of a common genetic cause, that the\nplanets rotate in a direction the same as that in which they go round\nthe Sun, and on axes approximately perpendicular to their orbits. Since\nhe wrote, an exception to this general rule has been discovered in the\ncase of Uranus, and another still more recently in the case of\nNeptune--judging, at least, from the motions of their respective\nsatellites. This anomaly has been thought to throw considerable doubt on\nhis speculation; and at first sight it does so. But a little reflection\nshows that the anomaly is not inexplicable, and that Laplace simply went\ntoo far in putting down as a certain result of nebular genesis, what is,\nin some instances, only a probable result. The cause he pointed out as\ndetermining the direction of rotation, is the greater absolute velocity\nof the outer part of the detached ring. But there are conditions under\nwhich this difference of velocity may be too insignificant, even if it\nexists. If a mass of nebulous matter approaching spirally to the central\nspheroid, and eventually joining it tangentially, is made up of parts\nhaving the same absolute velocities; then, after joining the equatorial\nperiphery of the spheroid and being made to rotate with it, the angular\nvelocity of its outer parts will be smaller than the angular velocity of\nits inner parts. Hence, if, when the angular velocities of the outer and\ninner parts of a detached ring are the same, there results a tendency to\nrotation in the same direction with the orbital motion, it may be\ninferred that when the outer parts of the ring have a smaller angular\nvelocity than the inner parts, a tendency to retrograde rotation will be\nthe consequence.\n\nAgain, the sectional form of the ring is a circumstance of moment; and\nthis form must have differed more or less in every case. To make this\nclear, some illustration will be necessary. Suppose we take an orange,\nand, assuming the marks of the stalk and the calyx to represent the\npoles, cut off round the line of the equator a strip of peel. This strip\nof peel, if placed on the table with its ends meeting, will make a ring\nshaped like the hoop of a barrel--a ring of which the thickness in the\nline of its diameter is very small, but of which the width in a\ndirection perpendicular to its diameter is considerable. Suppose, now,\nthat in place of an orange, which is a spheroid of very slight\noblateness, we take a spheroid of very great oblateness, shaped somewhat\nlike a lens of small convexity. If from the edge or equator of this\nlens-shaped spheroid, a ring of moderate size were cut off, it would be\nunlike the previous ring in this respect, that its greatest thickness\nwould be in the line of its diameter, and not in a line at right angles\nto its diameter: it would be a ring shaped somewhat like a quoit, only\nfar more slender. That is to say, according to the oblateness of a\nrotating spheroid, the detached ring may be either a hoop-shaped ring or\na quoit-shaped ring.\n\nOne further implication must be noted. In a much-flattened or\nlens-shaped spheroid, the form of the ring will vary with its bulk. A\nvery slender ring, taking off just the equatorial surface, will be\nhoop-shaped; while a tolerably massive ring, trenching appreciably on\nthe diameter of the spheroid, will be quoit-shaped. Thus, then,\naccording to the oblateness of the spheroid and the bulkiness of the\ndetached ring, will the greatest thickness of that ring be in the\ndirection of its plane, or in a direction perpendicular to its plane.\nBut this circumstance must greatly affect the rotation of the resulting\nplanet. In a decidedly hoop-shaped nebulous ring, the differences of\nvelocity between the inner and outer surfaces will be small; and such a\nring, aggregating into a mass of which the greatest diameter is at right\nangles to the plane of the orbit, will almost certainly give to this\nmass a predominant tendency to rotate in a direction at right angles to\nthe plane of the orbit. Where the ring is but little hoop-shaped, and\nthe difference between the inner and outer velocities greater, as it\nmust be, the opposing tendencies--one to produce rotation in the plane\nof the orbit, and the other, rotation perpendicular to it--will both be\ninfluential; and an intermediate plane of rotation will be taken up.\nWhile, if the nebulous ring is decidedly quoit-shaped, and therefore\naggregates into a mass whose greatest dimension lies in the plane of\nthe orbit, both tendencies will conspire to produce rotation in that\nplane.\n\nOn referring to the facts, we find them, as far as can be judged, in\nharmony with this view. Considering the enormous circumference of\nUranus's orbit, and his comparatively small mass, we may conclude that\nthe ring from which he resulted was a comparatively slender, and\ntherefore a hoop-shaped one: especially as the nebulous mass must have\nbeen at that time less oblate than afterwards. Hence, a plane of\nrotation nearly perpendicular to his orbit, and a direction of rotation\nhaving no reference to his orbital movement. Saturn has a mass seven\ntimes as great, and an orbit of less than half the diameter; whence it\nfollows that his genetic ring, having less than half the circumference,\nand less than half the vertical thickness (the spheroid being then\ncertainly _as_ oblate, and indeed _more_ oblate), must have had a much\ngreater width--must have been less hoop-shaped, and more approaching to\nthe quoit-shaped: notwithstanding difference of density, it must have\nbeen at least two or three times as broad in the line of its plane.\nConsequently, Saturn has a rotatory movement in the same direction as\nthe movement of translation, and in a plane differing from it by thirty\ndegrees only. In the case of Jupiter, again, whose mass is three and a\nhalf times that of Saturn, and whose orbit is little more than half the\nsize, the genetic ring must, for the like reasons, have been still\nbroader--decidedly quoit-shaped, we may say; and there hence resulted a\nplanet whose plane of rotation differs from that of his orbit by\nscarcely more than three degrees. Once more, considering the comparative\ninsignificance of Mars, Earth, Venus, and Mercury, it follows that, the\ndiminishing circumferences of the rings not sufficing to account for the\nsmallness of the resulting masses, the rings must have been slender\nones--must have again approximated to the hoop-shaped; and thus it\nhappens that the planes of rotation again diverge more or less widely\nfrom those of the orbits. Taking into account the increasing oblateness\nof the original spheroid in the successive stages of its concentration,\nand the different proportions of the detached rings, it may fairly be\nheld that the respective rotatory motions are not at variance with the\nhypothesis but contrariwise tend to confirm it.\n\nNot only the directions, but also the velocities of rotation seem thus\nexplicable. It might naturally be supposed that the large planets would\nrevolve on their axes more slowly than the small ones: our terrestrial\nexperiences of big and little bodies incline us to expect this. It is a\ncorollary from the Nebular Hypothesis, however, more especially when\ninterpreted as above, that while large planets will rotate rapidly,\nsmall ones will rotate slowly; and we find that in fact they do so.\nOther things equal, a concentrating nebulous mass which is diffused\nthrough a wide space, and whose outer parts have, therefore, to travel\nfrom great distances to the common centre of gravity, will acquire a\nhigh axial velocity in course of its aggregation; and conversely with a\nsmall mass. Still more marked will be the difference where the form of\nthe genetic ring conspires to increase the rate of rotation. Other\nthings equal, a genetic ring which is broadest in the direction of its\nplane will produce a mass rotating faster than one which is broadest at\nright angles to its plane; and if the ring is absolutely as well as\nrelatively broad, the rotation will be very rapid. These conditions\nwere, as we saw, fulfilled in the case of Jupiter; and Jupiter turns\nround his axis in less than ten hours. Saturn, in whose case, as above\nexplained, the conditions were less favourable to rapid rotation, takes\nnearly ten hours and a half. While Mars, Earth, Venus, and Mercury,\nwhose rings must have been slender, take more than double that time: the\nsmallest taking the longest.\n\n       *       *       *       *       *\n\nFrom the planets let us now pass to the satellites. Here, beyond the\nconspicuous facts commonly adverted to, that they go round their\nprimaries in the directions in which these turn on their axes, in planes\ndiverging but little from their equators, and in orbits nearly circular,\nthere are several significant traits which must not be passed over.\n\nOne of them is that each set of satellites repeats in miniature the\nrelations of the planets to the Sun, both in certain respects above\nnamed and in the order of their sizes. On progressing from the outside\nof the Solar System to its centre, we see that there are four large\nexternal planets, and four internal ones which are comparatively small.\nA like contrast holds between the outer and inner satellites in every\ncase. Among the four satellites of Jupiter, the parallel is maintained\nas well as the comparative smallness of the number allows: the two outer\nones are the largest, and the two inner ones the smallest. According to\nthe most recent observations made by Mr. Lassell, the like is true of\nthe four satellites of Uranus. In the case of Saturn, who has eight\nsecondary planets revolving round him, the likeness is still more close\nin arrangement as in number: the three outer satellites are large, the\ninner ones small; and the contrasts of size are here much greater\nbetween the largest, which is nearly as big as Mars, and the smallest,\nwhich is with difficulty discovered even by the best telescopes. But the\nanalogy does not end here. Just as with the planets, there is at first a\ngeneral increase of size on travelling inwards from Neptune and Uranus,\nwhich do not differ very widely, to Saturn, which is much larger, and to\nJupiter, which is the largest; so of the eight satellites of Saturn, the\nlargest is not the outermost, but the outermost save two; so of\nJupiter's four secondaries, the largest is the most remote but one. Now\nthese parallelisms are inexplicable by the theory of final causes. For\npurposes of lighting, if this be the presumed object of these attendant\nbodies, it would have been far better had the larger been the nearer: at\npresent, their remoteness renders them of less service than the\nsmallest. To the Nebular Hypothesis, however, these analogies give\nfurther support. They show the action of a common physical cause. They\nimply a _law_ of genesis, holding in the secondary systems as in the\nprimary system.\n\nStill more instructive shall we find the distribution of the\nsatellites--their absence in some instances, and their presence in other\ninstances, in smaller or greater numbers. The argument from design fails\nto account for this distribution. Supposing it be granted that planets\nnearer the Sun than ourselves, have no need of moons (though,\nconsidering that their nights are as dark, and, relatively to their\nbrilliant days, even darker than ours, the need seems quite as\ngreat)--supposing this to be granted; how are we to explain the fact\nthat Uranus has but half as many moons as Saturn, though he is at double\nthe distance? While, however, the current presumption is untenable, the\nNebular Hypothesis furnishes us with an explanation. It enables us to\npredict where satellites will be abundant and where they will be absent.\nThe reasoning is as follows.\n\nIn a rotating nebulous spheroid which is concentrating into a planet,\nthere are at work two antagonist mechanical tendencies--the centripetal\nand the centrifugal. While the force of gravitation draws all the atoms\nof the spheroid together, their tangential momentum is resolvable into\ntwo parts, of which one resists gravitation. The ratio which this\ncentrifugal force bears to gravitation, varies, other things equal, as\nthe square of the velocity. Hence, the aggregation of a rotating\nnebulous spheroid will be more or less hindered by this resisting force,\naccording as the rate of rotation is high or low: the opposition, in\nequal spheroids, being four times as great when the rotation is twice as\nrapid; nine times as great when it is three times as rapid; and so on.\nNow the detachment of a ring from a planet-forming body of nebulous\nmatter, implies that at its equatorial zone the increasing centrifugal\nforce consequent on concentration has become so great as to balance\ngravity. Whence it is tolerably obvious that the detachment of rings\nwill be most frequent from those masses in which the centrifugal\ntendency bears the greatest ratio to the gravitative tendency. Though it\nis not possible to calculate what ratio these two tendencies had to each\nother in the genetic spheroid which produced each planet, it is possible\nto calculate where each was the greatest and where the least. While it\nis true that the ratio which centrifugal force now bears to gravity at\nthe equator of each planet, differs widely from that which it bore\nduring the earlier stages of concentration; and while it is true that\nthis change in the ratio, depending on the degree of contraction each\nplanet has undergone, has in no two cases been the same; yet we may\nfairly conclude that where the ratio is still the greatest, it has been\nthe greatest from the beginning. The satellite-forming tendency which\neach planet had, will be approximately indicated by the proportion now\nexisting in it between the aggregating power, and the power that has\nopposed aggregation. On making the requisite calculations, a remarkable\nharmony with this inference comes out. The following table shows what\nfraction the centrifugal force is of the centripetal force in every\ncase; and the relation which that fraction bears to the number of\nsatellites.[18]\n\n   Mercury.  1/360\n   Venus.    1/253\n   Earth.    1/289    1 Satellite.\n   Mars.     1/127    2 Satellites.\n   Jupiter.  1/11.4   4 Satellites.\n   Saturn.   1/6.4    8 Satellites, and three rings.\n   Uranus.   1/10.9   4 Satellites.\n\nThus taking as our standard of comparison the Earth with its one moon,\nwe see that Mercury, in which the centrifugal force is relatively less,\nhas no moon. Mars, in which it is relatively much greater, has two\nmoons. Jupiter, in which it is far greater, has four moons. Uranus, in\nwhich it is greater still, has certainly four, and more if Herschel was\nright. Saturn, in which it is the greatest, being nearly one-sixth of\ngravity, has, including his rings, eleven attendants. The only instance\nin which there is nonconformity with observation, is that of Venus. Here\nit appears that the centrifugal force is relatively greater than in the\nEarth; and, according to the hypothesis, Venus ought to have a\nsatellite. Respecting this anomaly several remarks are to be made.\nWithout putting any faith in the alleged discovery of a satellite of\nVenus (repeated at intervals by five different observers), it may yet be\ncontended that as the satellites of Mars eluded observation up to 1877,\na satellite of Venus may have eluded observation up to the present time.\nMerely naming this as possible, but not probable, a consideration of\nmore weight is that the period of rotation of Venus is but indefinitely\nfixed, and that a small diminution in the estimated angular velocity of\nher equator would bring the result into congruity with the hypothesis.\nFurther, it may be remarked that not exact, but only general, congruity\nis to be expected; since the process of condensation of each planet from\nnebulous matter can scarcely be expected to have gone on with absolute\nuniformity: the angular velocities of the superposed strata of nebulous\nmatter probably differed from one another in degrees unlike in each\ncase; and such differences would affect the satellite-forming tendency.\nBut without making much of these possible explanations of the\ndiscrepancy, the correspondence between inference and fact which we find\nin so many planets, may be held to afford strong support to the Nebular\nHypothesis.\n\nCertain more special peculiarities of the satellites must be mentioned\nas suggestive. One of them is the relation between the period of\nrevolution and that of rotation. No discoverable purpose is served by\nmaking the Moon go round its axis in the same time that it goes round\nthe Earth: for our convenience, a more rapid axial motion would have\nbeen equally good; and for any possible inhabitants of the Moon, much\nbetter. Against the alternative supposition, that the equality occurred\nby accident, the probabilities are, as Laplace says, infinity to one.\nBut to this arrangement, which is explicable neither as the result of\ndesign nor of chance, the Nebular Hypothesis furnishes a clue. In his\n_Exposition du Systeme du Monde_, Laplace shows, by reasoning too\ndetailed to be here repeated, that under the circumstances such a\nrelation of movements would be likely to establish itself.\n\nAmong Jupiter's satellites, which severally display these same\nsynchronous movements, there also exists a still more remarkable\nrelation. \"If the mean angular velocity of the first satellite be added\nto twice that of the third, the sum will be equal to three times that of\nthe second;\" and \"from this it results that the situations of any two of\nthem being given, that of the third can be found.\" Now here, as before,\nno conceivable advantage results. Neither in this case can the connexion\nhave been accidental: the probabilities are infinity to one to the\ncontrary. But again, according to Laplace, the Nebular Hypothesis\nsupplies a solution. Are not these significant facts?\n\nMost significant fact of all, however, is that presented by the rings of\nSaturn. As Laplace remarks, they are, as it were, still extant witnesses\nof the genetic process he propounded. Here we have, continuing\npermanently, forms of aggregation like those through which each planet\nand satellite once passed; and their movements are just what, in\nconformity with the hypothesis, they should be. \"La duree de la rotation\nd'une planete doit donc etre, d'apres cette hypothese, plus petite que\nla duree de la revolution du corps le plus voisin qui circule autour\nd'elle,\" says Laplace. And he then points out that the time of Saturn's\nrotation is to that of his rings as 427 to 438--an amount of difference\nsuch as was to be expected.[19]\n\nRespecting Saturn's rings it may be further remarked that the place of\ntheir occurrence is not without significance.\n\nRings detached early in the process of concentration, consisting of\ngaseous matter having extremely little power of cohesion, can have\nlittle ability to resist the disruptive forces due to imperfect balance;\nand, therefore, collapse into satellites. A ring of a denser kind,\nwhether solid, liquid, or composed of small discrete masses (as Saturn's\nrings are now concluded to be), we can expect will be formed only near\nthe body of a planet when it has reached so late a stage of\nconcentration that its equatorial portions contain matters capable of\neasy precipitation into liquid and, finally, solid forms. Even then it\ncan be produced only under special conditions. Gaining a\nrapidly-increasing preponderance as the gravitative force does during\nthe closing stages of concentration, the centrifugal force cannot, in\nordinary cases, cause the leaving behind of rings when the mass has\nbecome dense. Only where the centrifugal force has all along been very\ngreat, and remains powerful to the last, as in Saturn, can we expect\ndense rings to be formed.\n\nWe find, then, that besides those most conspicuous peculiarities of the\nSolar System which first suggested the theory of its evolution, there\nare many minor ones pointing in the same direction. Were there no other\nevidence, these mechanical arrangements would, considered in their\ntotality, go far to establish the Nebular Hypothesis.\n\n       *       *       *       *       *\n\nFrom the mechanical arrangements of the Solar System, turn we now to its\nphysical characters; and, first, let us consider the inferences\ndeducible from relative specific gravities.\n\nThe fact that, speaking generally, the denser planets are the nearer to\nthe Sun, has been by some considered as adding another to the many\nindications of nebular origin. Legitimately assuming that the outermost\nparts of a rotating nebulous spheroid, in its earlier stages of\nconcentration, must be comparatively rare; and that the increasing\ndensity which the whole mass acquires as it contracts, must hold of the\noutermost parts as well as the rest; it is argued that the rings\nsuccessively detached will be more and more dense, and will form planets\nof higher and higher specific gravities. But passing over other\nobjections, this explanation is quite inadequate to account for the\nfacts. Using the Earth as a standard of comparison, the relative\ndensities run thus:--\n\n   Neptune. Uranus. Saturn. Jupiter. Mars. Earth. Venus. Mercury. Sun.\n    0.17     0.25    0.11    0.23    0.45   1.00   0.92   1.26    0.25\n\nTwo insurmountable objections are presented by this series. The first\nis, that the progression is but a broken one. Neptune is denser than\nSaturn, which, by the hypothesis, it ought not to be. Uranus is denser\nthan Jupiter, which it ought not to be. Uranus is denser than Saturn,\nand the Earth is denser than Venus--facts which not only give no\ncountenance to, but directly contradict, the alleged explanation. The\nsecond objection, still more manifestly fatal, is the low specific\ngravity of the Sun. If, when the matter of the Sun filled the orbit of\nMercury, its state of aggregation was such that the detached ring formed\na planet having a specific gravity equal to that of iron; then the Sun\nitself, now that it has concentrated, should have a specific gravity\nmuch greater than that of iron; whereas its specific gravity is only\nhalf as much again as that of water. Instead of being far denser than\nthe nearest planet, it is but one-fifth as dense.\n\nWhile these anomalies render untenable the position that the relative\nspecific gravities of the planets are direct indications of nebular\ncondensation; it by no means follows that they negative it. Several\ncauses may be assigned for these unlikenesses:--1. Differences among the\nplanets in respect of the elementary substances composing them; or in\nthe proportions of such elementary substances, if they contain the same\nkinds. 2. Differences among them in respect of the quantities of matter\nthey contain; for, other things equal, the mutual gravitation of\nmolecules will make a larger mass denser than a smaller. 3. Differences\nof temperatures; for, other things equal, those having higher\ntemperatures will have lower specific gravities. 4. Differences of\nphysical states, as being gaseous, liquid, or solid; or, otherwise,\ndifferences in the relative amounts of the solid, liquid, and gaseous\nmatter they contain.\n\nIt is quite possible, and we may indeed say probable, that all these\ncauses come into play, and that they take various shares in the\nproduction of the several results. But difficulties stand in the way of\ndefinite conclusions. Nevertheless, if we revert to the hypothesis of\nnebular genesis, we are furnished with partial explanations if nothing\nmore.\n\nIn the cooling of celestial bodies several factors are concerned. The\nfirst and simplest is the one illustrated at every fire-side by the\nrapid blackening of little cinders which fall into the ashes, in\ncontrast with the long-continued redness of big lumps. This factor is\nthe relation between increase of surface and increase of content:\nsurfaces, in similar bodies, increasing as the squares of the dimensions\nwhile contents increase as their cubes. Hence, on comparing the Earth\nwith Jupiter, whose diameter is about eleven times that of the Earth, it\nresults that while his surface is 125 times as great, his content is\n1390 times as great. Now even (supposing we assume like temperatures and\nlike densities) if the only effect were that through a given area of\nsurface eleven times more matter had to be cooled in the one case than\nin the other, there would be a vast difference between the times\noccupied in concentration. But, in virtue of a second factor, the\ndifference would be much greater than that consequent on these\ngeometrical relations. The escape of heat from a cooling mass is\neffected by conduction, or by convection, or by both. In a solid it is\nwholly by conduction; in a liquid or gas the chief part is played by\nconvection--by circulating currents which continually transpose the\nhotter and cooler parts. Now in fluid spheroids--gaseous, or liquid, or\nmixed--increasing size entails an increasing obstacle to cooling,\nconsequent on the increasing distances to be travelled by the\ncirculating currents. Of course the relation is not a simple one: the\nvelocities of the currents will be unlike. It is manifest, however, that\nin a sphere of eleven times the diameter, the transit of matter from\ncentre to surface and back from surface to centre, will take a much\nlonger time; even if its movement is unrestrained. But its movement is,\nin such cases as we are considering, greatly restrained. In a rotating\nspheroid there come into play retarding forces augmenting with the\nvelocity of rotation. In such a spheroid the respective portions of\nmatter (supposing them equal in their angular velocities round the axis,\nwhich they will tend more and more to become as the density increases),\nmust vary in their absolute velocities according to their distances from\nthe axis; and each portion cannot have its distance from the axis\nchanged by circulating currents, which it must continually be, without\nloss or gain in its quantity of motion: through the medium of fluid\nfriction, force must be expended, now in increasing its motion and now\nin retarding its motion. Hence, when the larger spheroid has also a\nhigher velocity of rotation, the relative slowness of the circulating\ncurrents, and the consequent retardation of cooling, must be much\ngreater than is implied by the extra distances to be travelled.\n\nAnd now observe the correspondence between inference and fact. In the\nfirst place, if we compare the group of the great planets, Jupiter,\nSaturn, and Uranus, with the group of the small planets, Mars, Earth,\nVenus, and Mercury, we see that low density goes along with great size\nand great velocity of rotation, and that high density goes along with\nsmall size and small velocity of rotation. In the second place, we are\nshown this relation still more clearly if we compare the extreme\ninstances--Saturn and Mercury. The special contrast of these two, like\nthe general contrast of the groups, points to the truth that low\ndensity, like the satellite-forming tendency, is associated with the\nratio borne by centrifugal force to gravity; for in the case of Saturn\nwith his many satellites and least density, centrifugal force at the\nequator is nearly 1/6th of gravity, whereas in Mercury with no satellite\nand greatest density centrifugal force is but 1/360th of gravity.\n\nThere are, however, certain factors which, working in an opposite way,\nqualify and complicate these effects. Other things equal, mutual\ngravitation among the parts of a large mass will cause a greater\nevolution of heat than is similarly caused in a small mass; and the\nresulting difference of temperature will tend to produce more rapid\ndissipation of heat. To this must be added the greater velocity of the\ncirculating currents which the intenser forces at work in larger\nspheroids will produce--a contrast made still greater by the relatively\nsmaller retardation by friction to which the more voluminous currents\nare exposed. In these causes, joined with causes previously indicated,\nwe may recognize a probable explanation of the otherwise anomalous fact\nthat the Sun, though having a thousand times the mass of Jupiter, has\nyet reached as advanced a stage of concentration. For the force of\ngravity in the Sun, which at his surface is some ten times that at the\nsurface of Jupiter, must expose his central parts to a pressure\nrelatively very intense; producing, during contraction, a relatively\nrapid genesis of heat. And it is further to be remarked that, though the\ncirculating currents in the Sun have far greater distances to travel,\nyet since his rotation is relatively so slow that the angular velocity\nof his substance is but about one-sixtieth of that of Jupiter's\nsubstance, the resulting obstacle to circulating currents is relatively\nsmall, and the escape of heat far less retarded. Here, too, we may note\nthat in the co-operation of these factors, there seems a reason for the\ngreater concentration reached by Jupiter than by Saturn, though Saturn\nis the elder as well as the smaller of the two; for at the same time\nthat the gravitative force in Jupiter is more than twice as great as in\nSaturn, his velocity of rotation is very little greater, so that the\nopposition of the centrifugal force to the centripetal is not much more\nthan half.\n\nBut now, not judging more than roughly of the effects of these several\nfactors, co-operating in various ways and degrees, some to aid\nconcentration and others to resist it, it is sufficiently manifest that,\nother things equal, the larger nebulous spheroids, longer in losing\ntheir heat, will more slowly reach high specific gravities; and that\nwhere the contrasts in size are so immense as those between the greater\nand the smaller planets, the smaller may have reached relatively high\nspecific gravities when the greater have reached but relatively low\nones. Further, it appears that such qualification of the process as\nresults from the more rapid genesis of heat in the larger masses, will\nbe countervailed where high velocity of rotation greatly impedes the\ncirculating currents. Thus interpreted then, the various specific\ngravities of the planets may be held to furnish further evidences\nsupporting the Nebular Hypothesis.\n\n       *       *       *       *       *\n\nIncrease of density and escape of heat are correlated phenomena, and\nhence in the foregoing section, treating of the respective densities of\nthe celestial bodies in connexion with nebular condensation, much has\nbeen said and implied respecting the accompanying genesis and\ndissipation of heat. Quite apart, however, from the foregoing arguments\nand inferences, there is to be noted the fact that in the present\ntemperatures of the celestial bodies at large we find additional\nsupports to the hypothesis; and these, too, of the most substantial\ncharacter. For if, as is implied above, heat must inevitably be\ngenerated by the aggregation of diffused matter, we ought to find in all\nthe heavenly bodies, either present high temperatures or marks of past\nhigh temperatures. This we do, in the places and in the degrees which\nthe hypothesis requires.\n\nObservations showing that as we descend below the Earth's surface there\nis a progressive increase of heat, joined with the conspicuous evidence\nfurnished by volcanoes, necessitate the conclusion that the temperature\nis very high at great depths. Whether, as some believe, the interior of\nthe Earth is still molten, or whether, as Sir William Thomson contends,\nit must be solid; there is agreement in the inference that its heat is\nintense. And it has been further shown that the rate at which the\ntemperature increases on descending below the surface, is such as would\nbe found in a mass which had been cooling for an indefinite period. The\nMoon, too, shows us, by its corrugations and its conspicuous extinct\nvolcanoes, that in it there has been a process of refrigeration and\ncontraction, like that which has gone on in the Earth. There is no\nteleological explanation of these facts. The frequent destructions of\nlife by earthquakes and volcanoes, imply, rather, that it would have\nbeen better had the Earth been created with a low internal temperature.\nBut if we contemplate the facts in connexion with the Nebular\nHypothesis, we see that this still-continued high internal heat is one\nof its corollaries. The Earth must have passed through the gaseous and\nthe molten conditions before it became solid, and must for an almost\ninfinite period by its internal heat continue to bear evidence of this\norigin.\n\nThe group of giant planets furnishes remarkable evidence. The _a priori_\ninference drawn above, that great size joined with relatively high ratio\nof centrifugal force to gravity must greatly retard aggregation, and\nmust thus, by checking the genesis and dissipation of heat, make the\nprocess of cooling a slow one, has of late years received verifications\nfrom inferences drawn _a posteriori_; so that now the current conclusion\namong astronomers is that in physical condition the great planets are in\nstages midway between that of the Earth and that of the Sun. The fact\nthat the centre of Jupiter's disc is twice or thrice as bright as his\nperiphery, joined with the facts that he seems to radiate more light\nthan is accounted for by reflection of the Sun's rays, and that his\nspectrum shows the \"red-star line\", are taken as evidences of\nluminosity; while the immense and rapid perturbations in his atmosphere,\nfar greater than could be caused by heat received from the Sun, as well\nas the formation of spots analogous to those of the Sun, which also,\nlike those of the Sun, show a higher rate of rotation near the equator\nthan further from it, are held to imply high internal temperature. Thus\nin Jupiter, as also in Saturn, we find states which, not admitting of\nany teleological explanations (for they manifestly exclude the\npossibility of life), admit of explanations derived from the Nebular\nHypothesis.\n\nBut the argument from temperature does not end here. There remains to be\nnoticed a more conspicuous and still more significant fact. If the Solar\nSystem was produced by the concentration of diffused matter, which\nevolved heat while gravitating into its present dense form; then there\nis an obvious implication. Other things equal, the latest-formed mass\nwill be the latest in cooling--will, for an almost infinite time,\npossess a greater heat than the earlier-formed ones. Other things equal,\nthe largest mass will, because of its superior aggregative force, become\nhotter than the others, and radiate more intensely. Other things equal,\nthe largest mass, notwithstanding the higher temperature it reaches,\nwill, in consequence of its relatively small surface, be the slowest in\nlosing its evolved heat. And hence, if there is one mass which was not\nonly formed after the rest, but exceeds them enormously in size, it\nfollows that this one will reach an intensity of incandescence far\nbeyond that reached by the rest; and will continue in a state of intense\nincandescence long after the rest have cooled. Such a mass we have in\nthe Sun. It is a corollary from the Nebular Hypothesis, that the matter\nforming the Sun assumed its present integrated shape at a period much\nmore recent than that at which the planets became definite bodies. The\nquantity of matter contained in the Sun is nearly five million times\nthat contained in the smallest planet, and above a thousand times that\ncontained in the largest. And while, from the enormous gravitative force\nof his parts to their common centre, the evolution of heat has been\nintense, the facilities of radiation have been relatively small. Hence\nthe still-continued high temperature. Just that condition of the central\nbody which is a necessary inference from the Nebular Hypothesis, we find\nactually existing in the Sun.\n\n[The paragraph which here follows, though it contains some questionable\npropositions, I reproduce just as it stood when first published in 1858,\nfor reasons which will presently be apparent.]\n\nIt may be well to consider more closely, what is the probable condition\nof the Sun's surface. Round the globe of incandescent molten substances,\nthus conceived to form the visible body of the Sun [which in conformity\nwith the argument in a previous section, now transferred to the Addenda,\nwas inferred to be hollow and filled with gaseous matter at high\ntension] there is known to exist a voluminous atmosphere: the inferior\nbrilliancy of the Sun's border, and the appearances during a total\neclipse, alike show this. What now must be the constitution of this\natmosphere? At a temperature approaching a thousand times that of molten\niron, which is the calculated temperature of the solar surface, very\nmany, if not all, of the substances we know as solid, would become\ngaseous; and though the Sun's enormous attractive force must be a\npowerful check on this tendency to assume the form of vapour, yet it\ncannot be questioned that if the body of the Sun consists of molten\nsubstances, some of them must be constantly undergoing evaporation. That\nthe dense gases thus continually being generated will form the entire\nmass of the solar atmosphere, is not probable. If anything is to be\ninferred, either from the Nebular Hypothesis, or from the analogies\nsupplied by the planets, it must be concluded that the outermost part of\nthe solar atmosphere consists of what are called permanent gases--gases\nthat are not condensible into fluid even at low temperatures. If we\nconsider what must have been the state of things here, when the surface\nof the Earth was molten, we shall see that round the still molten\nsurface of the Sun, there probably exists a stratum of dense aeriform\nmatter, made up of sublimed metals and metallic compounds, and above\nthis a stratum of comparatively rare medium analogous to air. What now\nwill happen with these two strata? Did they both consist of permanent\ngases, they could not remain separate: according to a well-known law,\nthey would eventually form a homogeneous mixture. But this will by no\nmeans happen when the lower stratum consists of matters that are gaseous\nonly at excessively high temperatures. Given off from a molten surface,\nascending, expanding, and cooling, these will presently reach a limit of\nelevation above which they cannot exist as vapour, but must condense and\nprecipitate. Meanwhile the upper stratum, habitually charged with its\nquantum of these denser matters, as our air with its quantum of water,\nand ready to deposit them on any depression of temperature, must be\nhabitually unable to take up any more of the lower stratum; and\ntherefore this lower stratum will remain quite distinct from it.[20]\n\n       *       *       *       *       *\n\nConsidered in their _ensemble_, the several groups of evidences assigned\namount almost to proof. We have seen that, when critically examined,\nthe speculations of late years current respecting the nature of the\nnebulae, commit their promulgators to sundry absurdities; while, on the\nother hand, we see that the various appearances these nebulae present,\nare explicable as different stages in the precipitation and aggregation\nof diffused matter. We find that the immense majority of comets (_i.e._\nomitting the periodic ones), by their physical constitution, their\nimmensely-extended and variously-directed paths, the distribution of\nthose paths, and their manifest structural relation to the Solar System,\nbear testimony to the past existence of that system in a nebulous form.\nNot only do those obvious peculiarities in the motions of the planets\nwhich first suggested the Nebular Hypothesis, supply proofs of it, but\non closer examination we discover, in the slightly-diverging\ninclinations of their orbits, in their various rates of rotation, and\ntheir differently-directed axes of rotation, that the planets yield us\nyet further testimony; while the satellites, by sundry traits, and\nespecially by their occurrence in greater or less abundance where the\nhypothesis implies greater or less abundance, confirm this testimony. By\ntracing out the process of planetary condensation, we are led to\nconclusions respecting the physical states of planets which explain\ntheir anomalous specific gravities. Once more, it turns out that what is\ninferable from the Nebular Hypothesis respecting the temperatures of\ncelestial bodies, is just what observation establishes; and that both\nthe absolute and the relative temperatures of the Sun and planets are\nthus accounted for. When we contemplate these various evidences in their\ntotality--when we observe that, by the Nebular Hypothesis, the leading\nphenomena of the Solar System, and the heavens in general, are\nexplicable; and when, on the other hand, we consider that the current\ncosmogony is not only without a single fact to stand on, but is at\nvariance with all our positive knowledge of Nature, we see that the\nproof becomes overwhelming.\n\nIt remains only to point out that while the genesis of the Solar System,\nand of countless other systems like it, is thus rendered comprehensible,\nthe ultimate mystery continues as great as ever. The problem of\nexistence is not solved: it is simply removed further back. The Nebular\nHypothesis throws no light on the origin of diffused matter; and\ndiffused matter as much needs accounting for as concrete matter. The\ngenesis of an atom is not easier to conceive than the genesis of a\nplanet. Nay, indeed, so far from making the Universe less a mystery than\nbefore, it makes it a greater mystery. Creation by manufacture is a much\nlower thing than creation by evolution. A man can put together a\nmachine; but he cannot make a machine develop itself. That our\nharmonious universe once existed potentially as formless diffused\nmatter, and has slowly grown into its present organized state, is a far\nmore astonishing fact than would have been its formation after the\nartificial method vulgarly supposed. Those who hold it legitimate to\nargue from phenomena to noumena, may rightly contend that the Nebular\nHypothesis implies a First Cause as much transcending \"the mechanical\nGod of Paley,\" as this does the fetish of the savage.\n\nFOOTNOTES:\n\n[Footnote 11: _Cosmos._ (Seventh Edition.) Vol. i. pp. 79, 80.]\n\n[Footnote 12: Since the publication of this essay the late Mr. R. A.\nProctor has given various further reasons for the conclusion that the\nnebulae belong to our own sidereal system. The opposite conclusion,\ncontested throughout the foregoing section, has now been tacitly\nabandoned.]\n\n[Footnote 13: Any objection made to the extreme tenuity this involves,\nis met by the calculation of Newton, who proved that were a spherical\ninch of air removed four thousand miles from the Earth, it would expand\ninto a sphere more than filling the orbit of Saturn.]\n\n[Footnote 14: A reference may fitly be made here to a reason given by\nMons. Babinet for rejection of the Nebular Hypothesis. He has calculated\nthat taking the existing Sun, with its observed angular velocity, its\nsubstance, if expanded so as to fill the orbit of Neptune, would have\nnothing approaching the angular velocity which the time of revolution of\nthat planet implies. The assumption he makes is inadmissible. He\nsupposes that all parts of the nebulous spheroid when it filled\nNeptune's orbit, had the same angular velocities. But the process of\nnebular condensation as indicated above, implies that the remoter\nflocculi of nebulous matter, later in reaching the central mass, and\nforming its peripheral portions, will acquire, during their longer\njourneys towards it, greater velocities. An inspection of one of the\nspiral nebulae, as 51st or 99th Messier, at once shows that the outlying\nportions when they reach the nucleus, will form an equatorial belt\nmoving round the common centre more rapidly than the rest. Thus the\ncentral parts will have small angular velocities, while there will be\nincreasing angular velocities of parts increasingly remote from the\ncentre. And while the density of the spheroid continues small, fluid\nfriction will scarcely at all change these differences.\n\nA like criticism may, I think, be passed on an opinion expressed by\nProf. Newcomb. He says:--\"When the contraction [of the nebulous\nspheroid] had gone so far that the centrifugal and attracting forces\nnearly balanced each other at the outer equatorial limit of the mass,\nthe result would have been that contraction in the direction of the\nequator would cease entirely, and be confined to the polar regions, each\nparticle dropping, not towards the sun, but towards the plane of the\nsolar equator. Thus, we should have a constant flattening of the\nspheroidal atmosphere until it was reduced to a thin flat disk. This\ndisk might then separate itself into rings, which would form planets in\nmuch the same way that Laplace supposed. But there would probably be no\nmarked difference in the age of the planets.\" (_Popular Astronomy_,\np. 512.) Now this conclusion assumes, like that of M. Babinet, that all\nparts of the nebulous spheroid had equal angular velocities. If, as\nabove contended, it is inferable from the process by which a nebulous\nspheroid was formed, that its outer portions revolved with greater\nangular velocities than its inner; then the inference which Prof.\nNewcomb draws is not necessitated.]\n\n[Footnote 15: It is true that since this essay was written reasons have\nbeen given for concluding that comets consist of swarms of meteors\nenveloped in aeriform matter. Very possibly this is the constitution of\nthe periodic comets which, approximating their orbits to the plane of\nthe Solar System, form established parts of the System, and which, as\nwill be hereafter indicated, have probably a quite different origin.]\n\n[Footnote 16: Though this rule fails at the periphery of the Solar\nSystem, yet it fails only where the axis of rotation, instead of being\nalmost perpendicular to the orbit-plane, is very little inclined to it;\nand where, therefore, the forces tending to produce the congruity of\nmotions were but little operative.]\n\n[Footnote 17: It is true that, as expressed by him, these propositions\nof Laplace are not all beyond dispute. An astronomer of the highest\nauthority, who has favoured me with some criticisms on this essay,\nalleges that instead of a nebulous ring rupturing at one point, and\ncollapsing into a single mass, \"all probability would be in favour of\nits breaking up into many masses.\" This alternative result certainly\nseems the more likely. But granting that a nebulous ring would break up\ninto many masses, it may still be contended that, since the chances are\ninfinity to one against these being of equal sizes _and_ equidistant,\nthey could not remain evenly distributed round their orbit. This annular\nchain of gaseous masses would break up into groups of masses; these\ngroups would eventually aggregate into larger groups; and the final\nresult would be the formation of a single mass. I have put the question\nto an astronomer scarcely second in authority to the one above referred\nto, and he agrees that this would probably be the process.]\n\n[Footnote 18: The comparative statement here given differs, slightly in\nmost cases and in one case largely, from the statement included in this\nessay as originally published in 1858. As then given the table ran\nthus:--\n\n   Mercury.   1/362\n   Venus.     1/282\n   Earth.     1/289   1 Satellite.\n   Mars.      1/326\n   Jupiter.   1/14    4 Satellites.\n   Saturn.    1/6.2   8 Satellites, and three rings.\n   Uranus.    1/9     4 (or 6 according to Herschel).\n\nThe calculations ending with these figures were made while the Sun's\ndistance was still estimated at 95 millions of miles. Of course the\nreduction afterwards established in the estimated distance, entailing,\nas it did, changes in the factors which entered into the calculations,\naffected the results; and, though it was unlikely that the relations\nstated would be materially changed, it was needful to have the\ncalculations made afresh. Mr. Lynn has been good enough to undertake\nthis task, and the figures given in the text are his. In the case of\nMars a large error in my calculation had arisen from accepting Arago's\nstatement of his density (0.95), which proves to be something like\ndouble what it should be. Here a curious incident may be named. When, in\n1877, it was discovered that Mars has two satellites, though, according\nto my hypothesis, it seemed that he should have none, my faith in it\nreceived a shock; and since that time I have occasionally considered\nwhether the fact is in any way reconcilable with the hypothesis. But now\nthe proof afforded by Mr. Lynn that my calculation contained a wrong\nfactor, disposes of the difficulty--nay, changes the objection to a\nverification. It turns out that, according to the hypothesis, Mars\n_ought_ to have satellites; and, further, that he ought to have a number\nintermediate between 1 and 4.]\n\n[Footnote 19: Since this paragraph was first published, the discovery\nthat Mars has two satellites revolving round him in periods shorter than\nthat of his rotation, has shown that the implication on which Laplace\nhere insists is general only, and not absolute. Were it a necessary\nassumption that all parts of a concentrating nebulous spheroid revolve\nwith the same angular velocities, the exception would appear an\ninexplicable one; but if, as suggested in a preceding section, it is\ninferable from the process of formation of a nebulous spheroid, that its\nouter strata will move round the general axis with higher angular\nvelocities than the inner ones, there follows a possible interpretation.\nThough, during the earlier stages of concentration, while the nebulous\nmatter, and especially its peripheral portions, are very rare, the\neffects of fluid-friction will be too small to change greatly such\ndifferences of angular velocities as exist; yet, when concentration has\nreached its last stages, and the matter is passing from the gaseous into\nthe liquid and solid states, and when also the convection-currents have\nbecome common to the whole mass (which they probably at first are not),\nthe angular velocity of the peripheral portion will gradually be\nassimilated to that of the interior; and it becomes comprehensible that\nin the case of Mars the peripheral portion, more and more dragged back\nby the internal mass, lost part of its velocity during the interval\nbetween the formation of the innermost satellite and the arrival at the\nfinal form.]\n\n[Footnote 20: I was about to suppress part of the above paragraph,\nwritten before the science of solar physics had taken shape, because of\ncertain physical difficulties which stand in the way of its argument,\nwhen, on looking into recent astronomical works, I found that the\nhypothesis it sets forth respecting the Sun's structure has kinships to\nthe several hypotheses since set forth by Zoellner, Faye, and Young. I\nhave therefore decided to let it stand as it originally did.\n\nThe contemplated partial suppression just named, was prompted by\nrecognition of the truth that to effect mechanical stability the gaseous\ninterior of the Sun must have a density at least equal to that of the\nmolten shell (greater, indeed, at the centre); and this seems to imply a\nspecific gravity higher than that which he possesses. It may, indeed, be\nthat the unknown elements which spectrum analysis shows to exist in the\nSun, are metals of very low specific gravities, and that, existing in\nlarge proportion with other of the lighter metals, they may form a\nmolten shell not denser than is implied by the facts. But this can be\nregarded as nothing more than a possibility.\n\nNo need, however, has arisen for either relinquishing or holding but\nloosely the associated conclusions respecting the constitution of the\nphotosphere and its envelope. Widely speculative as seemed these\nsuggested corollaries from the Nebular Hypothesis when set forth in\n1858, and quite at variance with the beliefs then current, they proved\nto be not ill-founded. At the close of 1859, there came the discoveries\nof Kirchhoff, proving the existence of various metallic vapours in the\nSun's atmosphere.]\n\n\n\n\nADDENDA.\n\n\nSpeculative as is much of the foregoing essay, it appears undesirable to\ninclude in it anything still more speculative. For this reason I have\ndecided to set forth separately some views concerning the genesis of the\nso-called elements during nebular condensation, and concerning the\naccompanying physical effects. At the same time it has seemed best to\ndetach from the essay some of the more debatable conclusions originally\ncontained in it; so that its general argument may not be needlessly\nimplicated with them. These new portions, together with the old portions\nwhich re-appear more or less modified, I here append in a series of\nnotes.\n\n\nNOTE I. For the belief that the so-called elements are compound there\nare both special reasons and general reasons. Among the special may be\nnamed the parallelism between allotropy and isomerism; the numerous\nlines in the spectrum of each element; and the cyclical law of Newlands\nand Mendeljeff. Of the more general reasons, which, as distinguished\nfrom these chemical or chemico-physical ones, may fitly be called\ncosmical, the following are the chief.\n\nThe general law of evolution, if it does not actually involve the\nconclusion that the so-called elements are compounds, yet affords _a\npriori_ ground for suspecting that they are such. The implication is\nthat, while the matter composing the Solar System has progressed\nphysically from that relatively-homogeneous state which it had as a\nnebula to that relatively-heterogeneous state presented by Sun, planets,\nand satellites, it has also progressed chemically, from the\nrelatively-homogeneous state in which it was composed of one or a few\ntypes of matter, to that relatively-heterogeneous state in which it is\ncomposed of many types of matter very diverse in their properties. This\ndeduction from the law which holds throughout the cosmos as now known to\nus, would have much weight even were it unsupported by induction; but a\nsurvey of chemical phenomena at large discloses several groups of\ninductive evidences supporting it.\n\nThe first is that since the cooling of the Earth reached an advanced\nstage, the components of its crust have been ever increasing in\nheterogeneity. When the so-called elements, originally existing in a\ndissociated state, united into oxides, acids, and other binary\ncompounds, the total number of different substances was immensely\naugmented, the new substances were more complex than the old, and their\nproperties were more varied. That is, the assemblage became more\nheterogeneous in its kinds, in the composition of each kind, and in the\nrange of chemical characters. When, at a later period, there arose salts\nand other compounds of similar degrees of complexity, there was again an\nincrease of heterogeneity, alike in the aggregate and in its members.\nAnd when, still later, matters classed as organic became possible, the\nmultiformity was yet further augmented in kindred ways. If, then,\nchemical evolution, so far as we can trace it, has been from the\nhomogeneous to the heterogeneous, may we not fairly suppose that it has\nbeen so from the beginning? If, from late stages in the Earth's history,\nwe run back, and find the lines of chemical evolution continually\nconverging, until they bring us to bodies which we cannot decompose, may\nwe not suspect that, could we run back these lines still further, we\nshould come to still decreasing heterogeneity in the number and nature\nof the substances, until we reached something like homogeneity?\n\nA parallel argument may be derived from consideration of the affinities\nand stabilities of chemical compounds. Beginning with the complex\nnitrogenous bodies out of which living things are formed, and which, in\nthe history of the Earth, are the most modern, at the same time that\nthey are the most heterogeneous, we see that the affinities and\nstabilities of these are extremely small. Their molecules do not enter\nbodily into union with those of other substances so as to form more\ncomplex compounds still, and their components often fail to hold\ntogether under ordinary conditions. A stage lower in degree of\ncomposition we come to the vast assemblage of oxy-hydro-carbons, numbers\nof which show many and decided affinities, and are stable at common\ntemperatures. Passing to the inorganic group, we are shown by the salts\n&c. strong affinities between their components and unions which are, in\nmany cases, not very easily broken. And then when we come to the oxides,\nacids, and other binary compounds, we see that in many cases the\nelements of which they are formed, when brought into the presence of one\nanother under favourable conditions, unite with violence; and that many\nof their unions cannot be dissolved by heat alone. If, then, as we go\nback from the most modern and most complex substances to the most\nancient and simplest substances, we see, on the average, a great\nincrease in affinity and stability, it results that if the same law\nholds with the simplest substances known to us, the components of these,\nif they are compound, may be assumed to have united with affinities far\nmore intense than any we have experience of, and to cling together with\ntenacities far exceeding the tenacities with which chemistry acquaints\nus. Hence the existence of a class of substances which are\nundecomposable and therefore seem simple, appears to be an implication;\nand the corollary is that these were formed during early stages of\nterrestrial concentration, under conditions of heat and pressure which\nwe cannot now parallel.\n\nYet another support for the belief that the so-called elements are\ncompounds, is derived from a comparison of them, considered as an\naggregate ascending in their molecular weights, with the aggregate of\nbodies known to be compound, similarly considered in their ascending\nmolecular weights. Contrast the binary compounds as a class with the\nquaternary compounds as a class. The molecules constituting oxides\n(whether alkaline or acid or neutral) chlorides, sulphurets, &c. are\nrelatively small; and, combining with great avidity, form stable\ncompounds. On the other hand, the molecules constituting nitrogenous\nbodies are relatively vast and are chemically inert; and such\ncombinations as their simpler types enter into, cannot withstand\ndisturbing forces. Now a like difference is seen if we contrast with one\nanother the so-called elements. Those of relatively-low molecular\nweights--oxygen, hydrogen, potassium, sodium, &c.,--show great readiness\nto unite among themselves; and, indeed, many of them cannot be prevented\nfrom uniting under ordinary conditions. Contrariwise, under ordinary\nconditions the substances of high molecular weights--the \"noble\nmetals\"--are indifferent to other substances; and such compounds as they\ndo form under conditions specially adjusted, are easily destroyed. Thus\nas, among the bodies we know to be compound, increasing molecular weight\nis associated with the appearance of certain characters, and as, among\nthe bodies we class as simple, increasing molecular weight is\nassociated with the appearance of similar characters, the composite\nnature of the elements is in another way pointed to.\n\nThere has to be added one further class of phenomena, congruous with\nthose above named, which here specially concerns us. Looking generally\nat chemical unions, we see that the heat evolved usually decreases as\nthe degree of composition, and consequent massiveness, of the molecules,\nincreases. In the first place, we have the fact that during the\nformation of simple compounds the heat evolved is much greater than that\nwhich is evolved during the formation of complex compounds: the\nelements, when uniting with one another, usually give out much heat;\nwhile, when the compounds they form are recompounded, but little heat is\ngiven out; and, as shown by the experiments of Prof. Andrews, the heat\ngiven out during the union of acids and bases is habitually smaller\nwhere the molecular weight of the base is greater. Then, in the second\nplace, we see that among the elements themselves, the unions of those\nhaving low molecular weights result in far more heat than do the unions\nof those having high molecular weights. If we proceed on the supposition\nthat the so-called elements are compounds, and if this law, if not\nuniversal, holds of undecomposable substances as of decomposable, then\nthere are two implications. The one is that those compoundings and\nrecompoundings by which the elements were formed, must have been\naccompanied by degrees of heat exceeding any degrees of heat known to\nus. The other is that among these compoundings and recompoundings\nthemselves, those by which the small-moleculed elements were formed\nproduced more intense heat than those by which the large-moleculed\nelements were formed: the elements formed by the final recompoundings\nbeing necessarily later in origin, and at the same time less stable,\nthan the earlier-formed ones.\n\n\nNOTE II. May we from these propositions, and especially from the last,\ndraw any conclusions respecting the evolution of heat during nebular\ncondensation? And do such conclusions affect in any way the conclusions\nnow current?\n\nIn the first place, it seems inferable from physico-chemical facts at\nlarge, that only through the instrumentality of those combinations which\nformed the elements, did the concentration of diffused nebulous matter\ninto concrete masses become possible. If we remember that hydrogen and\noxygen in their uncombined states oppose, the one an insuperable and the\nother an almost insuperable, resistance to liquefaction, while when\ncombined the compound assumes the liquid state with facility, we may\nsuspect that in like manner the simpler types of matter out of which the\nelements were formed, could not have been reduced even to such degrees\nof density as the known gases show us, without what we may call\nproto-chemical unions: the implication being that after the heat\nresulting from each of such proto-chemical unions had escaped, mutual\ngravitation of the parts was able to produce further condensation of the\nnebulous mass.\n\nIf we thus distinguish between the two sources of heat accompanying\nnebular condensation--the heat due to proto-chemical combinations and\nthat due to the contraction caused by gravitation (both of them,\nhowever, being interpretable as consequent on loss of motion), it may be\ninferred that they take different shares during the earlier and during\nthe later stages of aggregation. It seems probable that while the\ndiffusion is great and the force of mutual gravitation small, the chief\nsource of heat is combination of units of matter, simpler than any known\nto us, into such units of matter as those we know; while, conversely,\nwhen there has been reached close aggregation, the chief source of heat\nis gravitation, with consequent pressure and gradual contraction.\nSupposing this to be so, let us ask what may be inferred. If at the time\nwhen the nebulous spheroid from which the Solar System resulted, filled\nthe orbit of Neptune, it had reached such a degree of density as\nenabled those units of matter which compose the sodium molecules to\nenter into combination; and if, in conformity with the analogies above\nindicated, the heat evolved by this proto-chemical combination was great\ncompared with the heats evolved by the chemical combinations known to\nus; the implication is that the nebulous spheroid, in the course of its\ncontraction, would have to get rid of a much larger quantity of heat\nthan it would, did it commence at any ordinary temperature and had only\nto lose the heat consequent on contraction. That is to say, in\nestimating the past period during which solar emission of heat has been\ngoing on at a high rate, much must depend on the initial temperature\nassumed; and this may have been rendered intense by the proto-chemical\nchanges which took place in early stages.[21]\n\nRespecting the future duration of the solar heat, there must also be\ndifferences between the estimates made according as we do or do not take\ninto account the proto-chemical changes which possibly have still to\ntake place. True as it may be that the quantity of heat to be emitted\nis measured by the quantity of motion to be lost, and that this must be\nthe same whether the approximation of the molecules is effected by\nchemical unions, or by mutual gravitation, or by both; yet, evidently,\neverything must turn on the degree of condensation supposed to be\neventually reached; and this must in large measure depend on the natures\nof the substances eventually formed. Though, by spectrum-analysis,\nplatinum has recently been detected in the solar atmosphere, it seems\nclear that the metals of low molecular weights greatly predominate; and\nsupposing the foregoing arguments to be valid, it may be inferred, as\nnot improbable, that the compoundings and recompoundings by which the\nheavy-moleculed elements are produced, not hitherto possible in large\nmeasure, will hereafter take place; and that, as a result, the Sun's\ndensity will finally become very great in comparison with what it is\nnow. I say \"not hitherto possible in large measure\", because it is a\nfeasible supposition that they may be formed, and can continue to exist,\nonly in certain outer parts of the Solar mass, where the pressure is\nsufficiently great while the heat is not too great. And if this be so,\nthe implication is that the interior body of the Sun, higher in\ntemperature than its peripheral layers, may consist wholly of the metals\nof low atomic weights, and that this may be a part cause of his low\nspecific gravity; and a further implication is that when, in course of\ntime, the internal temperature falls, the heavy-moleculed elements, as\nthey severally become capable of existing in it, may arise: the\nformation of each having an evolution of heat as its concomitant.[22] If\nso, it would seem to follow that the amount of heat to be emitted by\nthe Sun, and the length of the period during which the emission will go\non, must be taken as much greater than if the Sun is supposed to be\npermanently constituted of the elements now predominating in him, and to\nbe capable of only that degree of condensation which such composition\npermits.\n\n\nNOTE III. Are the internal structures of celestial bodies all the same,\nor do they differ? And if they differ, can we, from the process of\nnebular condensation, infer the conditions under which they assume one\nor other character? In the foregoing essay as originally published,\nthese questions were discussed; and though the conclusions reached\ncannot be sustained in the form given to them, they foreshadow\nconclusions which may, perhaps, be sustained. Referring to the\nconceivable causes of unlike specific gravities in the members of the\nsolar system, it was said that these might be--\n\n     \"1. Differences between the kinds of matter or matters composing\n     them. 2. Differences between the quantities of matter; for, other\n     things equal, the mutual gravitation of atoms will make a large\n     mass denser than a small one. 3. Differences between the\n     structures: the masses being either solid or liquid throughout, or\n     having central cavities filled with elastic aeriform substance. Of\n     these three conceivable causes, that commonly assigned is the\n     first, more or less modified by the second.\"\n\nWritten as this was before spectrum-analysis had made its disclosures,\nno notice could of course be taken of the way in which these conflict\nwith the first of the foregoing suppositions; but after pointing out\nother objections to it the argument continued thus:--\n\n     \"However, spite of these difficulties, the current hypothesis is,\n     that the Sun and planets, inclusive of the Earth, are either solid\n     or liquid, or have solid crusts with liquid nuclei.\"[23]\n\nAfter saying that the familiarity of this hypothesis must not delude us\ninto uncritical acceptance of it, but that if any other hypothesis is\nphysically possible it may reasonably be entertained, it was argued that\nby tracing out the process of condensation in a nebulous spheroid, we\nare led to infer the eventual formation of a molten shell with a nucleus\nconsisting of gaseous matter at high tension. The paragraph which then\nfollows runs thus:--\n\n     \"But what,\" it may be asked, \"will become of this gaseous nucleus\n     when exposed to the enormous gravitative pressure of a shell some\n     thousands of miles thick? How can aeriform matter withstand such a\n     pressure?\" Very readily. It has been proved that, even when the\n     heat generated by compression is allowed to escape, some gases\n     remain uncondensible by any force we can produce. An unsuccessful\n     attempt lately made in Vienna to liquify oxygen, clearly shows this\n     enormous resistance. The steel piston employed was literally\n     shortened by the pressure used; and yet the gas remained\n     unliquified! If, then, the expansive force is thus immense when the\n     heat evolved is dissipated, what must it be when that heat is in\n     great measure detained, as in the case we are considering? Indeed\n     the experiences of M. Cagniard de Latour have shown that gases may,\n     under pressure, acquire the density of liquids while retaining the\n     aeriform state, provided the temperature continues extremely high.\n     In such a case, every addition to the heat is an addition to the\n     repulsive power of the atoms: the increased pressure itself\n     generates an increased ability to resist; and this remains true to\n     whatever extent the compression is carried. Indeed it is a\n     corollary from the persistence of force that if, under increasing\n     pressure, a gas retains all the heat evolved, its resisting force\n     is _absolutely unlimited_. Hence the internal planetary structure\n     we have described is as physically stable a one as that commonly\n     assumed.\"\n\nHad this paragraph, and the subsequent paragraphs, been written five\nyears later, when Prof. Andrews had published an account of his\nresearches, the propositions they contain, while rendered more specific\nand at the same time more defensible, would perhaps have been freed from\nthe erroneous implication that the internal structure indicated is an\nuniversal one. Let us, while guided by Prof. Andrews' results, consider\nwhat would probably be the successive changes in a condensing nebulous\nspheroid.\n\nProf. Andrews has shown that for each kind of gaseous matter there is a\ntemperature above which no amount of pressure can cause liquefaction.\nThe remark, made _a priori_ in the above extract, \"that if, under\nincreasing pressure, a gas retains all the heat evolved, its\nresisting force is _absolutely unlimited_\", harmonizes with the\ninductively-reached result that if the temperature is not lowered to its\n\"critical point\" a gas does not liquify, however great the force\napplied. At the same time Prof. Andrews' experiments imply that,\nsupposing the temperature to be lowered to the point at which\nliquefaction becomes possible, then liquefaction will take place where\nthere is first reached the required pressure. What are the corollaries\nin relation to concentrating nebulous spheroids?\n\nAssume a spheroid of such size as will form one of the inferior planets,\nand consisting externally of a voluminous, cloudy atmosphere composed of\nthe less condensible elements, and internally of metallic gases: such\ninternal gases being kept by convection-currents at temperatures not\nvery widely differing. And assume that continuous radiation has brought\nthe internal mass of metallic gases down to the critical point of the\nmost condensible. May we not say that there is a size of the spheroid\nsuch that the pressure will not be great enough to produce liquefaction\nat any other place than the centre? or, in other words, that in the\nprocess of decreasing temperature and increasing pressure, the centre\nwill be the place at which the combined conditions of pressure and\ntemperature will be first reached? If so, liquefaction, commencing at\nthe centre, will spread thence to the periphery; and, in virtue of the\nlaw that solids have higher melting points under pressure than when\nfree, it may be that solidification will similarly, at a later stage,\nbegin at the centre and progress outwards: eventually producing, in that\ncase, a state such as Sir William Thomson alleges exists in the Earth.\nBut now suppose that instead of such a spheroid, we assume one of, say,\ntwenty or thirty times the mass; what will then happen? Notwithstanding\nconvection-currents, the temperature at the centre must always be\nhigher than elsewhere; and in the process of cooling the \"critical\npoint\" of temperature will sooner be reached in the outer parts. Though\nthe requisite pressure will not exist near the surface, there is\nevidently, in a large spheroid, a depth below the surface at which the\npressure will be great enough, if the temperature is sufficiently low.\nHence it is inferable that somewhere between centre and surface in the\nsupposed larger spheroid, there will arise that state described by Prof.\nAndrews, in which \"flickering striae\" of liquid float in gaseous matter\nof equal density. And it may be inferred that gradually, as the process\ngoes on, these striae will become more abundant while the gaseous\ninterspaces diminish; until, eventually, the liquid becomes continuous.\nThus there will result a molten shell containing a gaseous nucleus\nequally dense with itself at their surface of contact and more dense at\nthe centre--a molten shell which will slowly thicken by additions to\nboth exterior and interior.\n\nThat a solid crust will eventually form on this molten shell may be\nreasonably concluded. To the demurrer that solidification cannot\ncommence at the surface, because the solids formed would sink, there are\ntwo replies. The first is that various metals expand while solidifying,\nand therefore would float. The second is that since the envelope of the\nsupposed spheroid would consist of the gases and non-metallic elements,\ncompounds of these with the metals and with one another would\ncontinually accumulate on the molten shell; and the crust, consisting of\noxides, chlorides, sulphurets, and the rest, having much less specific\ngravity than the molten shell, would be readily supported by it.\n\nClearly a planet thus constituted would be in an unstable state. Always\nit would remain liable to a catastrophe resulting from change in its\ngaseous nucleus. If, under some condition of pressure and temperature\neventually reached, the components of this suddenly entered into one of\nthose proto-chemical combinations forming a new element, there might\nresult an explosion capable of shattering the entire planet, and\npropelling its fragments in all directions with high velocities. If the\nhypothetical planet between Jupiter and Mars was intermediate in size as\nin position, it would apparently fulfil the conditions under which such\na catastrophe might occur.\n\n\nNOTE IV. The argument set forth in the foregoing note, is in part\ndesigned to introduce a question which seems to require\nre-consideration--the origin of the minor planets or planetoids. The\nhypothesis of Olbers, as propounded by him, implied that the disruption\nof the assumed planet between Mars and Jupiter had taken place at no\nvery remote period in the past; and this implication was shown to be\ninadmissible by the discovery that there exists no such point of\nintersection of the orbits of the planetoids as the hypothesis requires.\nThe inquiry whether, in the past, there was any nearer approach to a\npoint of intersection than at present, having resulted in a negative, it\nis held that the hypothesis must be abandoned. It is, however, admitted\nthat the mutual perturbations of the planetoids themselves would\nsuffice, in the course of some millions of years, to destroy all traces\nof a place of intersection of their orbits, if it once existed. But if\nthis be admitted why need the hypothesis be abandoned? Given such\nduration of the Solar System as is currently assumed, there seems no\nreason why lapse of a few millions of years should present any\ndifficulty. The explosion may as well have taken place ten million years\nago as at any more recent period. And whoever grants this must grant\nthat the probability of the hypothesis has to be estimated from other\ndata.\n\nAs a preliminary to closer consideration, let us ask what may be\ninferred from the rate of discovery of the planetoids, and from the\nsizes of those most recently discovered. In 1878, Prof. Newcomb, arguing\nthat \"the preponderance of evidence is on the side of the number and\nmagnitude being limited\", says that \"the newly discovered ones\" \"do not\nseem, on the average, to be materially smaller than those which were\ndiscovered ten years ago\"; and further that \"the new ones will probably\nbe found to grow decidedly rare before another hundred are discovered\".\nNow, inspection of the tables contained in the just-published fourth\nedition of Chambers' _Descriptive Astronomy_ (vol. I) shows that whereas\nthe planetoids discovered in 1868 (the year Prof. Newcomb singles out\nfor comparison) have an average magnitude of 11.56 those discovered last\nyear (1888) have an average magnitude of 12.43. Further, it is\nobservable that though more than ninety have been discovered since Prof.\nNewcomb wrote, they have by no means become rare: the year 1888 having\nadded ten to the list, and having therefore maintained the average rate\nof the preceding ten years. If, then, the indications Prof. Newcomb\nnames, had they arisen, would have implied a limitation of the number,\nthese opposite indications imply that the number is unlimited. The\nreasonable conclusion appears to be that these minor planets are to be\ncounted not by hundreds but by thousands; that more powerful telescopes\nwill go on revealing still smaller ones; and that additions to the list\nwill cease only when the smallness ends in invisibility.\n\nCommencing now to scrutinize the two hypotheses respecting the genesis\nof these multitudinous bodies, I may first remark concerning that of\nLaplace, that he might possibly not have propounded it had he known that\ninstead of four such bodies there are hundreds, if not thousands. The\nsupposition that they resulted from the breaking up of a nebulous ring\ninto numerous small portions, instead of its collapse into one mass,\nmight not, in such case, have seemed to him so probable. It would have\nappeared still less probable had he been aware of all that has since\nbeen discovered concerning the wide differences of the orbits in size,\ntheir various and often great eccentricities, and their various and\noften great inclinations. Let us look at these and other incongruous\ntraits of them.\n\n(1.) Between the greatest and least mean distances of the planetoids\nthere is a space of 200 millions of miles; so that the whole of the\nEarth's orbit might be placed between the limits of the zone occupied,\nand leave 7 millions of miles on either side: add to which that the\nwidest excursions of the planetoids occupy a zone of 270 millions of\nmiles. Had the rings from which Mercury, Venus, and the Earth were\nformed been one-sixth of the smaller width or one-ninth of the greater,\nthey would have united: there would have been no nebulous rings at all,\nbut a continuous disk. Nay more, since one of the planetoids trenches\nupon the orbit of Mars, it follows that the nebulous ring out of which\nthe planetoids were formed must have overlapped that out of which Mars\nwas formed. How do these implications consist with the nebular\nhypothesis? (2.) The tacit assumption usually made is that the different\nparts of a nebulous ring have the same angular velocities. Though this\nassumption may not be strictly true, yet it seems scarcely likely that\nit is so widely untrue as it would be had the inner part of the ring an\nangular velocity nearly thrice that of the outer. Yet this is implied.\nWhile the period of Thule is 8.8 years, the period of Medusa is 3.1\nyears. (3.) The eccentricity of Jupiter's orbit is 0.04816, and the\neccentricity of Mars' orbit is 0.09311. Estimated by groups of the first\nfound and last found of the planetoids, the average eccentricity of the\nassemblage is about three times that of Jupiter and more than one and a\nhalf times that of Mars; and among the members of the assemblage\nthemselves, some have an eccentricity thirty-five times that of others.\nHow came this nebulous zone, out of which it is supposed the planetoids\narose, to have originated eccentricities so divergent from one another\nas well as from those of the neighbouring planets? (4.) A like question\nmay be asked respecting the inclinations of the orbits. The average\ninclination of the planetoid-orbits is four times the inclination of\nMars' orbit and six times the inclination of Jupiter's orbit; and among\nthe planetoid-orbits themselves the inclinations of some are fifty times\nthose of others. How are all these differences to be accounted for on\nthe hypothesis of genesis from a nebulous ring? (5.) Much greater\nbecomes the difficulty on inquiring how these extremely unlike\neccentricities and inclinations came to co-exist before the parts of the\nnebulous ring separated, and how they survived after the separation.\nWere all the great eccentricities displayed by the outermost members of\nthe group, and the small by the innermost members, and were the\ninclinations so distributed that the orbits having much belonged to one\npart of the group, and those having little to another part of the group;\nthe difficulty of explanation might not be insuperable. But the\narrangement is by no means this. The orbits are, to use an expressive\nword, miscellaneously jumbled. Hence, if we go back to the nebulous\nring, there presents itself the question,--How came each\nplanetoid-forming portion of nebulous matter, when it gathered itself\ntogether and separated, to have a motion round the Sun differing so much\nfrom the motions of its neighbours in eccentricity and inclination? And\nthere presents itself the further question,--How, during the time when\nit was concentrating into a planetoid, did it manage to jostle its way\nthrough all the differently-moving like masses of nebulous matter, and\nyet to preserve its individuality? Answers to these questions are, it\nseems to me, not even imaginable.\n\n       *       *       *       *       *\n\nTurn we now to the alternative hypothesis. During revision of the\nforegoing essay, in preparation for that edition of the volume\ncontaining it which was published in 1883, there occurred the thought\nthat some light on the origin of the planetoids ought to be obtained by\nstudy of their distributions and movements. If, as Olbers supposed,\nthey resulted from the bursting of a planet once revolving in the region\nthey occupy, the implications are:--first, that the fragments must be\nmost abundant in the space immediately about the original orbit, and\nless abundant far away from it; second, that the large fragments must be\nrelatively few, while of smaller fragments the numbers will increase as\nthe sizes decrease; third, that as some among the smaller fragments will\nbe propelled further than any of the larger, the widest deviations in\nmean distance from the mean distance of the original planet, will be\npresented by the smallest members of the assemblage; and fourth, that\nthe orbits differing most from the rest in eccentricity and in\ninclination, will be among those of these smallest members. In the\nfourth edition of Chambers's _Handbook of Descriptive and Practical\nAstronomy_ (the first volume of which has just been issued) there is a\nlist of the elements (extracted and adapted from the _Berliner\nAstronomisches Jahrbuch_ for 1890) of all the small planets (281 in\nnumber) which had been discovered up to the end of 1888. The apparent\nbrightness, as expressed in equivalent star-magnitudes, is the only\nindex we have to the probable comparative sizes of by far the largest\nnumber of the planetoids: the exceptions being among those first\ndiscovered. Thus much premised, let us take the above points in order.\n(1) There is a region lying between 2.50 and 2.80 (in terms of the\nEarth's mean distance from the Sun) where the planetoids are found in\nmaximum abundance. The mean between these extremes, 2.65, is nearly the\nsame as the average of the distances of the four largest and\nearliest-known of these bodies, which amounts to 2.64. May we not say\nthat the thick clustering about this distance (which is, however, rather\nless than that assigned for the original planet by Bode's empirical\nlaw), in contrast with the wide scattering of the comparatively few\nwhose distances are little more than 2 or exceed 3, is a fact in\naccordance with the hypothesis in question?[24] (2) Any table which\ngives the apparent magnitudes of the planetoids, shows at once how much\nthe number of the smaller members of the assemblage exceeds that of\nthose which are comparatively large; and every succeeding year has\nemphasized this contrast more strongly. Only one of them (Vesta) exceeds\nin brightness the seventh star-magnitude, while one other (Ceres) is\nbetween the seventh and eighth, and a third (Pallas) is above the\neighth; but between the eighth and ninth there are six; between the\nninth and tenth, twenty; between the tenth and eleventh, fifty-five;\nbelow the eleventh a much larger number is known, and the number\nexisting is probably far greater,--a conclusion we cannot doubt when the\ndifficulty of finding the very faint members of the family, visible only\nin the largest telescopes, is considered. (3) Kindred evidence is\nfurnished if we broadly contrast their mean distances. Out of the 13\nlargest planetoids whose apparent brightnesses exceed that of a star of\nthe 9.5 magnitude, there is not one having a mean distance that exceeds\n3. Of those having magnitudes at least 9.5 and smaller than 10, there\nare 15; and of these one only has a mean distance greater than 3. Of\nthose between 10 and 10.5 there are 17; and of these also there is one\nexceeding 3 in mean distance. In the next group there are 37, and of\nthese 5 have this great mean distance. The next group, 48, contains 12\nsuch; the next, 47, contains 13 such. Of those of the twelfth magnitude\nand fainter, 72 planetoids have been discovered, and of those of them\nof which the orbits have been computed, no fewer than 23 have a mean\ndistance exceeding 3 in terms of the Earth's. It is evident from this\nhow comparatively erratic are the fainter members of the extensive\nfamily with which we are dealing. (4) To illustrate the next point, it\nmay be noted that among the planetoids whose sizes have been\napproximately measured, the orbits of the two largest, Vesta and Ceres,\nhave eccentricities falling between .05 and .10, whilst the orbits of\nthe two smallest, Menippe and Eva, have eccentricities falling between\n.20 and .25, and between .30 and .35. And then among those more recently\ndiscovered, having diameters so small that measurement of them has not\nbeen practicable, come the extremely erratic ones,--Hilda and Thule,\nwhich have mean distances of 3.97 and 4.25 respectively; AEthra, having\nan orbit so eccentric that it cuts the orbit of Mars; and Medusa, which\nhas the smallest mean distance from the Sun of any. (5) If the average\neccentricities of the orbits of the planetoids grouped according to\ntheir decreasing sizes are compared, no very definite results are\ndisclosed, excepting this, that the eight Polyhymnia, Atalanta,\nEurydice, AEthra, Eva, Andromache, Istria, and Eudora, which have the\ngreatest eccentricities (falling between .30 and .38), are all among\nthose of smallest star-magnitudes. Nor when we consider the inclinations\nof the orbits do we meet with obvious verifications; since the\nproportion of highly-inclined orbits among the smaller planetoids does\nnot appear to be greater than among the others. But consideration shows\nthat there are two ways in which these last comparisons are vitiated.\nOne is that the inclinations are measured from the plane of the\necliptic, instead of being measured from the plane of the orbit of the\nhypothetical planet. The other, and more important one, is that the\nsearch for planetoids has naturally been carried on in that\ncomparatively narrow zone within which most of their orbits fall; and\nthat, consequently, those having the most highly-inclined orbits are the\nleast likely to have been detected, especially if they are at the same\ntime among the smallest. Moreover, considering the general relation\nbetween the inclination of planetoid orbits and their eccentricities, it\nis probable that among the orbits of these undetected planetoids are\nmany of the most eccentric. But while recognizing the incompleteness of\nthe evidence, it seems to me that it goes far to justify the hypothesis\nof Olbers, and is quite incongruous with that of Laplace. And as having\nthe same meanings let me not omit the remarkable fact concerning the\nplanetoids discovered by D'Arrest, that \"if their orbits are figured\nunder the form of material rings, these rings will be found so\nentangled, that it would be possible, by means of one among them taken\nat hazard, to lift up all the rest,\"--a fact incongruous with Laplace's\nhypothesis, which implies an approximate concentricity, but quite\ncongruous with the hypothesis of an exploded planet.\n\nNext to be considered come phenomena, the bearings of which on the\nquestion before us are scarcely considered--I mean those presented by\nmeteors and shooting stars. The natures and distributions of these\nharmonize with the hypothesis of an exploded planet, and I think with no\nother hypothesis. The theory of volcanic origin, joined with the remark\nthat the Sun emits jets which might propel them with adequate\nvelocities, seems quite untenable. Such meteoric bodies as have\ndescended to us, forbid absolutely the supposition of solar origin. Nor\ncan they rationally be ascribed to planetary volcanoes. Even were their\nmineral characters appropriate, which many of them are not (for\nvolcanoes do not eject iron), no planetary volcanoes could propel them\nwith anything like the implied velocity--could no more withstand the\ntremendous force to be assumed, than could a card-board gun the force\nbehind a rifle bullet. But that their mineral characters, various as\nthey are, harmonize with the supposition that they were derived from\nthe crust of a planet is manifest; and that the bursting of a planet\nmight give to them, and to shooting stars, the needful velocities, is a\nreasonable conclusion. Along with those larger fragments of the crust\nconstituting the known planetoids, varying from some 200 miles in\ndiameter to little over a dozen, there would be sent out still more\nmultitudinous portions of the crust, decreasing in size as they\nincreased in number. And while there would thus result such masses as\noccasionally fall through the Earth's atmosphere to its surface, there\nwould, in an accompanying process, be an adequate cause for the myriads\nof far smaller masses which, as shooting stars, are dissipated in\npassing through the Earth's atmosphere. Let us figure to ourselves, as\nwell as we may, the process of explosion.\n\nAssume that the diameter of the missing planet was 20,000 miles; that\nits solid crust was a thousand miles thick; that under this came a shell\nof molten metallic matter which was another thousand miles thick; and\nthat the space, 16,000 miles in diameter, within this, was occupied by\nthe equally dense mass of gases above the \"critical point\", which,\nentering into a proto-chemical combination, caused the destroying\nexplosion. The primary fissures in the crust must have been far\napart--probably averaging distances between them as great as the\nthickness of the crust. Supposing them approximately equidistant, there\nwould, in the equatorial periphery, be between 60 and 70 fissures. By\nthe time the primary fragments thus separated had been heaved a mile\noutwards, the fissures formed would severally have, at the surface, a\nwidth of 170 odd yards. Of course these great masses, as soon as they\nmoved, would themselves begin to fall in pieces; especially at their\nbounding surfaces. But passing over the resulting complications, we see\nthat when the masses had been propelled 10 miles outwards, the fissures\nbetween them would be each a mile wide. Notwithstanding the enormous\nforces at work, an appreciable interval would elapse before these vast\nportions of the crust could be put in motion with any considerable\nvelocities. Perhaps the estimate will be under the mark if we assume\nthat it took 10 seconds to propel them through the first mile, and that,\nby implication, at the end of 20 seconds they had travelled 4 miles, and\nat the end of 30 seconds 9 miles. Supposing this granted, let us ask\nwhat would be taking place in each intervening fissure a thousand miles\ndeep, which, in the space of half a minute, had opened out to nearly a\nmile wide, and in the subsequent half minute to a chasm approaching 3\nmiles in width. There would first be propelled through it enormous jets\nof the molten metals composing the internal liquid shell; and these\nwould part into relatively small masses as they were shot into space.\nPresently, as the chasm opened to some miles in width, the molten metals\nwould begin to be followed by the equally dense gaseous matter behind,\nand the two would rush out together. Soon the gases, predominating,\nwould carry with them the portions of the liquid shell continually\ncollapsing; until the blast became one filled with millions of small\nmasses, billions of smaller masses, and trillions of drops. These would\nbe driven into space in a stream, the emission of which would continue\nfor many seconds or even several minutes. Remembering the rate of motion\nof the jets emitted from the solar surface, and supposing that the\nblasts produced by this explosion reached only one-tenth of that rate,\nthese myriads of small masses and drops would be propelled with\nplanetary velocities, and in approximately the same direction. I say\napproximately, because they would be made to deviate somewhat by the\nfriction and irregularities of the chasm passed through, and also by the\nrotation of the planet. Observe, however, that though they would all\nhave immense velocities, their velocities would not be equal. During its\nearlier stages the blast would be considerably retarded by the\nresistance which the sides of its channel offered. When this became\nrelatively small the velocity of the blast would reach its maximum; from\nwhich it would decline when the space for emission became very wide,\nand the pressure behind consequently less. Hence these almost infinitely\nnumerous particles of planet-spray, as we might call it, as well as\nthose formed by the condensation of the metallic vapours accompanying\nthem, would forthwith begin to part company: some going rapidly in\nadvance, and others falling behind; until the stream of them,\nperpetually elongating, formed an orbit round the Sun, or rather an\nassemblage of innumerable orbits, separating widely at aphelion and\nperihelion, but approximating midway, where they might fall within a\nspace of, say, some two millions of miles, as do the orbits of the\nNovember meteors. At a later stage of the explosion, when the large\nmasses, having moved far outwards, had also fallen to pieces of every\nsize, from that of Vesta to that of an aerolite, and when the channels\njust described had ceased to exist, the contents of the planet would\ndisperse themselves with lower velocities and without any unity of\ndirection. Hence we see causes alike for the streams of shooting stars,\nfor the solitary shooting stars visible to the naked eye, and for the\ntelescopic shooting stars a score times more numerous.\n\nFurther significant evidence is furnished by the comets of short\nperiods. Of the thirteen constituting this group, twelve have orbits\nfalling between those of Mars and Jupiter: one only having its aphelion\nbeyond the orbit of Jupiter. That is to say, nearly all of them frequent\nthe same region as the planetoids. By implication, they are similarly\nassociated in respect of their periods. The periods of the planetoids\nrange from 3.1 to 8.8 years; and all these twelve comets have periods\nfalling between these extremes: the least being 3.29 and the greatest\n8.86. Once more this family of comets, like the planetoids in the zone\nthey occupy and like them in their periods, are like them also in the\nrespect that, as Mr. Lynn has pointed out, their motions are all direct.\nHow happens this close kinship--how happens there to be this family of\ncomets so much like the planetoids and so much like one another, but so\nunlike comets at large? The obvious suggestion is that they are among\nthe products of the explosion which originated the planetoids, the\naerolites, and the streams of meteors; and consideration of the probable\ncircumstances shows us that such products might be expected. If the\nhypothetical planet was like its neighbour Jupiter in having an\natmosphere, or like its neighbour Mars in having water on its surface,\nor like both in these respects; then these superficial masses of liquid,\nof vapour, and of gas, blown into space along with the solid matters,\nwould yield the materials for comets. There would result, too, comets\nunlike one another in constitution. If a fissure opened beneath one of\nthe seas, the molten metals and metallic gases rushing through it as\nabove described, would decompose part of the water carried with them;\nand the oxygen and hydrogen liberated would be mingled with undecomposed\nvapour. In other cases, portions of the atmosphere might be propelled,\nprobably with portions of vapour; and in yet other cases masses of water\nalone. Severally subject to great heat at perihelion, these would behave\nmore or less differently. Once more, it would ordinarily happen that\ndetached swarms of meteors projected as implied, would carry with them\nmasses of vapours and gases; whence would result the cometic\nconstitution now insisted on. And sometimes there would be like\naccompaniments to meteoric streams.\n\nSee, then, the contrast between the two hypotheses. That of Laplace,\nlooking probable while there were only four planetoids, but decreasing\nin apparent likelihood as the planetoids increase in number, until, as\nthey pass through the hundreds on their way to the thousands, it becomes\nobviously improbable, is, at the same time, otherwise objectionable. It\npre-supposes a nebulous ring of a width so enormous that it would have\noverlapped the ring of Mars. This ring would have had differences\nbetween the angular velocities of its parts quite inconsistent with the\nNebular Hypothesis. The average eccentricities of the orbits of its\nparts must have differed greatly from those of adjacent orbits; and the\naverage inclinations of the orbits of its parts must similarly have\ndiffered greatly from those of adjacent orbits. Once more, the orbits of\nits parts, confusedly interspersed, must have had varieties of\neccentricity and inclination unaccountable in portions of the same\nnebulous ring; and, during concentration into planetoids, each must have\nhad to maintain its course while struggling through the assemblage of\nother small nebulous masses, severally moving in ways unlike its own. On\nthe other hand, the hypothesis of an exploded planet is supported by\nevery increase in the number of planetoids discovered; by the greater\nnumbers of the smaller sizes; by the thicker clustering near the\ninferred place of the missing planet; by the occurrence of the greatest\nmean distances among the smallest members of the assemblage; by the\noccurrence of the greatest eccentricities in the orbits of these\nsmallest members; and by the entanglement of all the orbits. Further\nsupport for the hypothesis is yielded by aerolites, so various in their\nkinds, but all suggestive of a planet's crust; by the streams of\nshooting stars having their radiant points variously placed in the\nheavens; and also by the solitary shooting stars visible to the naked\neye, and the more numerous ones visible through telescopes. Once more,\nit harmonizes with the discovery of a family of comets, twelve out of\nthirteen of which have mean distances falling within the zone of the\nplanetoids, have similarly associated periods, have all the same direct\nmotions, and are connected with swarms of meteors and with meteoric\nstreams. May we not, indeed, say, that if there once existed a planet\nbetween Mars and Jupiter which burst, the explosion must have produced\njust such clusters of bodies and classes of phenomena as we actually\nfind?\n\nAnd what is the objection? Merely that if such an explosion occurred it\nmust have occurred many millions of years ago--an objection which is in\nfact no objection; for the supposition that the explosion occurred many\nmillions of years ago is just as reasonable as the supposition that it\noccurred recently.\n\nIt is, indeed, further objected that some of the resulting fragments\nought to have retrograde motions. It turns out on calculation, however,\nthat this is not the case. Assuming as true the velocity which Lagrange\nestimated would have sufficed to give the four chief planetoids the\npositions they occupy, it results that such a velocity, given to the\nfragments which were propelled backwards by the explosion, would not\nhave given them retrograde motions, but would simply have reduced their\ndirect motions from something over 11 miles per second to about 6 miles\nper second. It is, however, manifest that this reduction of velocity\nwould have necessitated the formation of highly-elliptic orbits--more\nelliptic than any of those at present known. This seems to me the most\nserious difficulty which has presented itself. Still, considering that\nthere remain probably an immense number of planetoids to be discovered,\nit is quite possible that among these there may be some having orbits\nanswering to the requirement.\n\n\nNOTE V. Shortly before I commenced the revision of the foregoing essay,\nfriends on two occasions named to me some remarkable photographs of\nnebulae recently obtained by Mr. Isaac Roberts, and exhibited at the\nRoyal Astronomical Society: saying that they presented appearances such\nas might have been sketched by Laplace in illustration of his\nhypothesis. Mr. Roberts has been kind enough to send me copies of the\nphotographs in question and sundry others illustrative of stellar\nevolution. Those representing the Great Nebulae in Andromeda and Canum\nVenaticorum as well as 81 Messier are at once impressive and\ninstructive--illustrating as they do the genesis of nebulous rings round\na central mass.\n\nI may remark, however, that they seem to suggest the need for some\nmodification of the current conception; since they make it tolerably\nclear that the process is a much less uniform one than is supposed. The\nusual idea is that a vast rotating nebulous spheroid arises before there\nare produced any of the planet-forming rings. But both of these\nphotographs apparently imply that, in some cases at any rate, the\nportions of nebulous matter composing the rings take shape before they\nreach the central mass. It looks as though these partially-formed annuli\nmust be prevented by their acquired motions from approaching even very\nnear to the still-irregular body they surround.\n\nBe this as it may, however, and be the dimensions of the incipient\nsystems what they may (and it would seem to be a necessary implication\nthat they are vastly larger than our Solar System), the process remains\nessentially the same. Practically demonstrated as this process now is,\nwe may say that the doctrine of nebular genesis passes from the region\nof hypothesis into the region of established truth.\n\nFOOTNOTES:\n\n[Footnote 21: Of course there remains the question whether, before the\nstage here recognized, there had already been produced a high\ntemperature by those collisions of celestial masses which reduced the\nmatter to a nebulous form. As suggested in _First Principles_ (Sec. 136 in\nthe edition of 1862, and Sec. 182 in subsequent editions), there must,\nafter there have been effected all those minor dissolutions which follow\nevolutions, remain to be effected the dissolutions of the great bodies\nin and on which the minor evolutions and dissolutions have taken place;\nand it was argued that such dissolutions will be, at some time or other,\neffected by those immense transformations of molar motion into molecular\nmotion, consequent on collisions: the argument being based on the\nstatement of Sir John Herschel, that in clusters of stars collisions\nmust inevitably occur. It may, however, be objected that though such a\nresult may be reasonably looked for in closely aggregated assemblages of\nstars, it is difficult to conceive of its taking place throughout our\nSidereal System at large, the members of which, and their intervals, may\nbe roughly figured as pins-heads 50 miles apart. It would seem that\nsomething like an eternity must elapse before, by ethereal resistance or\nother cause, these can be brought into proximity great enough to make\ncollisions probable.]\n\n[Footnote 22: The two sentences which, in the text, precede the\nasterisk, I have introduced while these pages are standing in type:\nbeing led to do so by the perusal of some notes kindly lent to me by\nProf. Dewar, containing the outline of a lecture he gave at the Royal\nInstitution during the session of 1880. Discussing the conditions under\nwhich, if \"our so-called elements are compounded of elemental matter\",\nthey may have been formed, Prof. Dewar, arguing from the known habitudes\nof compound substances, concludes that the formation is in each case a\nfunction of pressure, temperature, and nature of the environing gases.]\n\n[Footnote 23: At the date of this passage the established teleology made\nit seem needful to assume that all the planets are habitable, and that\neven beneath the photosphere of the Sun there exists a dark body which\nmay be the scene of life; but since then, the influence of teleology has\nso far diminished that this hypothesis can no longer be called the\ncurrent one.]\n\n[Footnote 24: It may here be mentioned (though the principal\nsignificance of this comes under the next head) that the average mean\ndistance of the later-discovered planetoids is somewhat greater than\nthat of these earlier-discovered; amounting to 2.61 for Nos. 1 to 35 and\n2.80 for Nos. 211 to 245. For this observation I am indebted to Mr.\nLynn; whose attention was drawn to it while revising for me the\nstatements contained in this paragraph, so as to include discoveries\nmade since the paragraph was written.]\n\n\n\n\nTHE CONSTITUTION OF THE SUN.\n\n    [_First published in_ The Reader _for February_ 25, 1865. _I\n    reproduce this essay chiefly to give a place to the speculation\n    concerning the solar spots which forms the latter portion of it._]\n\n\nThe hypothesis of M. Faye, described in your numbers for January 28 and\nFebruary 4, respectively, is to a considerable extent coincident with\none which I ventured to suggest in an article on \"Recent Astronomy and\nthe Nebular Hypothesis,\" published in the _Westminster Review_ for July,\n1858. In considering the possible causes of the immense differences of\nspecific gravity among the planets, I was led to question the validity\nof the tacit assumption that each planet consists of solid or liquid\nmatter from centre to surface. It seemed to me that any other internal\nstructure which was mechanically stable, might be assumed with equal\nlegitimacy. And the hypothesis of a solid or liquid shell, having its\ncavity filled with gaseous matter at high pressure and temperature [and\nof great density], was one which seemed worth considering.\n\nHence arose the inquiry--What structure will result from the process of\nnebular condensation? [Here followed a long speculation respecting the\nprocesses going on in a concentrating nebulous spheroid; the general\noutcome of which is implied in Note III of the foregoing essay. I do not\nreproduce it because, not having the guidance of Prof. Andrew's\nresearches, I had concluded that the formation of a molten shell would\noccur universally, instead of occasionally, as is now argued in the\nnote named. The essay then proceeded thus:--]\n\nThe process of condensation being in its essentials the same for all\nconcentrating nebular spheroids, planetary or solar, it was argued that\nthe Sun is still passing through that incandescent stage which all the\nplanets have long ago passed through: his later aggregation, joined with\nthe immensely greater ratio of his mass to his surface, involving\ncomparative lateness of cooling. Supposing the sun to have reached the\nstate of a molten shell, inclosing a gaseous nucleus, it was concluded\nthat this molten shell, ever radiating its heat, but ever acquiring\nfresh heat by further integration of the Sun's mass, must be constantly\nkept up to that temperature at which its substance evaporates.\n\n[Here followed part of the paragraph quoted in the preceding essay on p.\n155; and there succeeded, in subsequent editions, a paragraph aiming to\nshow that the inferred structure of the Sun's interior was congruous\nwith the low specific gravity of the Sun--a conclusion which, as\nindicated on p. 156, implies some very problematical assumptions\nrespecting the natures of the unknown elements of the Sun. There then\ncame this passage:--]\n\nThe conception of the Sun's constitution thus set forth, is like that of\nM. Faye in so far as the successive changes, the resulting structures,\nand the ultimate state, are concerned; but unlike it in so far as the\nSun is supposed to have reached a later stage of concentration. As I\ngather from your abstract of M. Faye's paper [this referred to an\narticle in _The Reader_], he considers the Sun to be at present a\ngaseous spheroid, having an envelope of metallic matters precipitated in\nthe shape of luminous clouds, the local dispersions of which, caused by\ncurrents from within, appear to us as spots; and he looks forward to the\nfuture formation of a liquid film as an event that will soon be followed\nby extinction. Whereas the above hypothesis is that the liquid film\nalready exists beneath the visible photosphere, and that extinction\ncannot result until, in the course of further aggregation, the gaseous\nnucleus has become so much reduced, and the shell so much thickened,\nthat the escape of the heat generated is greatly retarded.... M. Faye's\nhypothesis appears to be espoused by him, partly because it affords an\nexplanation of the spots, which are considered as openings in the\nphotosphere, exposing the comparatively non-luminous gases filling the\ninterior. But if these interior gases are non-luminous from the absence\nof precipitated matter, must they not for the same reason be\ntransparent? And if transparent, will not the light from the remote side\nof the photosphere seen through them, be nearly as bright as that of the\nside next to us? By as much as the intensely-heated gases of the\ninterior are disabled by the dissociation of their molecules from giving\noff luminiferous undulations, by so much must they be disabled from\nabsorbing the light transmitted through them. And if their great\nlight-transmitting power is exactly complementary to their small\nlight-emitting power, there seems no reason why the interior of the Sun,\ndisclosed to us by openings in the photosphere, should not appear as\nbright as its exterior.\n\nTake, on the other hand, the supposition that a more advanced state of\nconcentration has been reached. A shell of molten metallic matter\nenclosing a gaseous nucleus still higher in temperature than itself,\nwill be continually kept at the highest temperature consistent with its\nstate of liquid aggregation. Unless we assume that simple radiation\nsuffices to give off all the heat generated by progressing integration,\nwe must conclude that the mass will be raised to that temperature at\nwhich part of its heat is absorbed in vaporizing its superficial parts.\nThe atmosphere of metallic gases hence resulting, cannot continue to\naccumulate without reaching a height above the Sun's surface, at which\nthe cooling due to radiation and rarefaction will cause condensation\ninto cloud--cannot, indeed, cease accumulating until the precipitation\nfrom the upper limit of the atmosphere balances the evaporation from its\nlower limit. This upper limit of the atmosphere of metallic gases,\nwhence precipitation is perpetually taking place, will form the visible\nphotosphere--partly giving off light of its own, partly letting through\nthe more brilliant light of the incandescent mass below. This conclusion\nharmonizes with the appearances. Sir John Herschel, advocating though he\ndoes an antagonist hypothesis, gives a description of the Sun's surface\nwhich agrees completely with the processes here supposed. He says:--\n\n     \"There is nothing which represents so faithfully this appearance as\n     the slow subsidence of some flocculent chemical precipitates in a\n     transparent fluid, when viewed perpendicularly from above: so\n     faithfully, indeed, that it is hardly possible not to be impressed\n     with the idea of a luminous medium intermixed, but not confounded,\n     with a transparent and non-luminous atmosphere, either floating as\n     clouds in our air, or pervading it in vast sheets and columns like\n     flame, or the streamers of our northern lights\".--_Treatise on\n     Astronomy_, p. 208.\n\nIf the constitution of the Sun be that which is above inferred, it does\nnot seem difficult to conceive still more specifically the production of\nthese appearances. Everywhere throughout the atmosphere of metallic\nvapours which clothes the solar surface, there must be ascending and\ndescending currents. The magnitude of these currents must obviously\ndepend on the depth of this atmosphere. If it is shallow, the currents\nmust be small; but if many thousands of miles deep, the currents may be\nwide enough to render visible to us the places at which they severally\nimpinge on the limit of the atmosphere, and the places whence the\ndescending currents commence. The top of an ascending current will be a\nspace over which the thickness of condensed cloud is the least, and\nthrough which the greatest amount of light from beneath penetrates. The\nclouds perpetually formed at the top of such a current, will be\nperpetually thrust aside by the uncondensed gases from below them; and,\ngrowing while they are thrust aside, will collect in the spaces between\nthe ascending currents, where there will result the greatest degree of\nopacity. Hence the mottled appearance--hence the \"pores,\" or dark\ninterspaces, separating the light-giving spots.[25]\n\nOf the more special appearances which the photosphere presents, let us\ntake first the faculae. These are ascribed to waves in the photosphere;\nand the way in which such waves might produce an excess of light has\nbeen variously explained in conformity with various hypotheses. What\nwould result from them in a photosphere constituted and conditioned as\nabove supposed? Traversing a canopy of cloud, here thicker and there\nthinner, a wave would cause a disturbance very unlikely to leave the\nthin and thick parts without any change in their average permeability to\nlight. There would probably be, at some parts of the wave, extensions in\nthe areas of the light-transmitting clouds, resulting in the passage of\nmore rays from below. Another phenomenon, less common but more striking,\nappears also to be in harmony with the hypothesis. I refer to those\nbright spots, of a brilliancy greater than that of the photosphere,\nwhich are sometimes observed. In the course of a physical process so\nvast and so active as that here supposed to be going on in the Sun, we\nmay expect that concurrent causes will occasionally produce ascending\ncurrents much hotter than usual, or more voluminous, or both. One of\nthese, on reaching the stratum of luminous and illuminated cloud forming\nthe photosphere, will burst through it, dispersing and dissolving it,\nand ascending to a greater height before it begins itself to condense:\nmeanwhile allowing to be seen, through its transparent mass, the\nincandescent molten shell of the sun's body.\n\n[The foregoing passages, to most of which I do not commit myself as more\nthan possibilities, I republish chiefly as introductory to the following\nspeculation, which, since it was propounded in 1865, has met with some\nacceptance.]\n\n\"But what of the spots commonly so called?\" it will be asked. In the\nessay on the Nebular hypothesis, above quoted from, it was suggested\nthat refraction of the light passing through the depressed centres of\ncyclones in this atmosphere of metallic gases, might possibly be the\ncause; but this, though defensible as a \"true cause,\" appeared on\nfurther consideration to be an inadequate cause. Keeping the question in\nmind, however, and still taking as a postulate the conclusion of Sir\nJohn Herschel, that the spots are in some way produced by cyclones, I\nwas led, in the course of the year following the publication of the\nessay, to an hypothesis which seemed more satisfactory. This, which I\nnamed at the time to Prof. Tyndall, had a point in common with the one\nafterward published by Prof. Kirchhoff, in so far as it supposed cloud\nto be the cause of darkness; but differed in so far as it assigned the\ncause of such cloud. More pressing matters prevented me from developing\nthe idea for some time; and, afterwards, I was deterred from including\nit in the revised edition of the essay, by its inconsistency with the\n\"willow-leaf\" doctrine, at that time dominant. The reasoning was as\nfollows:--The central region of a cyclone must be a region of\nrarefaction, and, consequently, a region of refrigeration. In an\natmosphere of metallic gases rising from a molten surface, and presently\nreaching a limit at which condensation takes place, the molecular state,\nespecially toward its upper part, must be such that a moderate\ndiminution of density, and fall of temperature, will cause\nprecipitation. That is to say, the rarefied interior of a solar cyclone\nwill be filled with cloud: condensation, instead of taking place only\nat the level of the photosphere, will here extend to a great depth below\nit, and over a wide area. What will be the characters of a cloud thus\noccupying the interior of a cyclone? It will have a rotatory motion; and\nthis it has been seen to have. Being funnel-shaped, as analogy warrants\nus in assuming, its central parts will be much deeper than its\nperipheral parts, and therefore more opaque. This, too, corresponds with\nobservation. Mr. Dawes has discovered that in the middle of the spot\nthere is a blacker spot: just where there would exist a funnel-shaped\nprolongation of the cyclonic cloud down toward the Sun's body, the\ndarkness is greater than elsewhere. Moreover, there is furnished an\nadequate reason for the depression which one of these dark spaces\nexhibits. In a whirlwind, as in a whirlpool, the vortex will be below\nthe general level, and all around, the surface of the medium will\ndescend toward it. Hence a spot seen obliquely, as when carried toward\nthe Sun's limb, will have its umbra more and more hidden, while its\npenumbra still remains visible. Nor are we without some interpretation\nof the penumbra. If, as is implied by what has been said, the so-called\n\"willow-leaves,\" or \"rice-grains,\" are the tops of the currents\nascending from the Sun's body, what changes of appearance are they\nlikely to undergo in the neighbourhood of a cyclone? For some distance\nround a cyclone there will be a drawing in of the superficial gases\ntoward the vortex. All the luminous spaces of more transparent cloud\nforming the adjacent photosphere, will be changed in shape by these\ncentripetal currents. They will be greatly elongated; and there will so\nbe produced that \"thatch\"-like aspect which the penumbra presents.\n\n       *       *       *       *       *\n\n[The explanation of the solar spots above suggested, which was\noriginally propounded in opposition to that of M. Faye, was eventually\nadopted by him in place of his own. In the _Comptes Rendus_ for 1867,\nVol. LXIV., p. 404, he refers to the article in the _Reader_, partly\nreproduced above, and speaks of me as having been replied to in a\nprevious note. Again in the _Comptes Rendus_ for 1872, Vol. LXXV., p.\n1664, he recognizes the inadequacy of his hypothesis, saying:--\"Il est\ncertain que l'objection de M. Spencer, reproduit et developpee par M.\nKirchoff, est fondee jusqu'a un certain point; l'interieur des taches,\nsi ce sont des lacunes dans la photosphere, doit etre froid\nrelativement.... Il est donc impossible qu'elles proviennent d'eruptions\nascendantes.\" He then proceeds to set forth the hypothesis that the\nspots are caused by the precipitation of vapour in the interiors of\ncyclones. But though, as above shown, he refers to the objection made in\nthe foregoing essay to his original hypothesis, and recognizes its\ncogency, he does not say that the hypothesis which he thereupon\nsubstitutes is also to be found in the foregoing essay. Nor does he\nintimate this in the elaborate paper on the subject read before the\nFrench Association for the Advancement of Science, and published in the\n_Revue Scientifique_ for the 24th March 1883. The result is that the\nhypothesis is now currently ascribed to him.[26]\n\nAbout four months before I had to revise this essay on \"The Constitution\nof the Sun,\" while staying near Pewsey, in Wiltshire, I was fortunate\nenough to witness a phenomenon which furnished, by analogy, a\nverification of the above hypothesis, and served more especially to\nelucidate one of the traits of solar spots, otherwise difficult to\nunderstand. It was at the close of August, when there had been a spell\nof very hot weather. A slight current of air from the West, moving along\nthe line of the valley, had persisted through the day, which, up to 5\no'clock, had been cloudless, and, with the exception now to be named,\nremained cloudless. The exception was furnished by a strange-looking\ncloud almost directly overhead. Its central part was comparatively dense\nand structureless. Its peripheral part, or to speak strictly, the\ntwo-thirds of it which were nearest and most clearly visible, consisted\nof _converging streaks_ of comparatively thin cloud. Possibly the third\npart on the remoter side was similarly constituted; but this I could not\nsee. It did not occur to me at the time to think about its cause,\nthough, had the question been raised, I should doubtless have concluded\nthat as the sky still remained cloudless everywhere else, this\nprecipitated mass of vapour must have resulted from a local eddy. In the\nspace of perhaps half-an-hour, the gentle breeze had carried this cloud\nsome miles to the East; and now its nature became obvious. That central\npart which, seen from underneath, seemed simply a dense, confused part,\napparently no nearer than the rest, now, seen sideways, was obviously\nmuch lower than the rest and rudely funnel-shaped--nipple-shaped one\nmight say; while the wide thin portion of cloud above it was\ndisk-shaped: the converging streaks of cloud being now, in perspective,\nmerged together. It thus became manifest that the cloud was produced by\na feeble whirlwind, perhaps a quarter to half-a-mile in diameter.\nFurther, the appearances made it clear that this feeble whirlwind was\nlimited to the lower stratum of air: the stratum of air above it was not\nimplicated in the cyclonic action. And then, lastly, there was the\nstriking fact that the upper stratum, though not involved in the whirl,\nwas, by its proximity to a region of diminished pressure, slightly\nrarified; and that its precipitated vapour was, by the draught set up\ntowards the vortex below, drawn into converging streaks. Here, then, was\nan action analogous to that which, as above suggested, happens around a\nsun-spot, where the masses of illuminated vapour constituting the\nphotosphere are drawn towards the vortex of the cyclone, and\nsimultaneously elongated into striae: so forming the penumbra. At the\nsame time there was furnished an answer to the chief objection to the\ncyclonic theory of solar spots. For if, as here seen, a cyclone in a\nlower stratum may fail to communicate a vortical motion to the stratum\nabove it, we may comprehend how, in a solar cyclone, the photosphere\ncommonly fails to give any indication of the revolving currents below,\nand is only occasionally so entangled in these currents as itself to\ndisplay a vortical motion.\n\nLet me add that apart from the elucidations furnished by the phenomenon\nabove described, the probabilities are greatly in favour of the cyclonic\norigin of the solar spots. That some of them exhibit clear marks of\nvortical motion is undeniable; and if this is so, the question\narises--What is the degree of likelihood that there are two causes for\nspots? Considering that they have so many characters in common, it is\nextremely improbable that their common characters are in some cases the\nconcomitants of vortical motion and in other cases the concomitants of a\ndifferent kind of action. Recognizing this great improbability, even in\nthe absence of a reconciliation between the apparently conflicting\ntraits, it is, I think, clear that when, in the way above shown, we are\nenabled to understand how it happens that the vortical motion, not\nordinarily implicating the photosphere, may consequently be in most\ncases unapparent, the reasons for accepting the cyclonic theory become\nalmost conclusive.]\n\nFOOTNOTES:\n\n[Footnote 25: If the \"rice-grain\" appearance is thus produced by the\ntops of the ascending currents (and M. Faye accepts this\ninterpretation), then I think it excludes M. Faye's hypothesis that the\nSun is gaseous throughout. The comparative smallness of the light-giving\nspots and their comparative uniformity of size, show us that they have\nascended through a stratum of but moderate depth (say 10,000 miles), and\nthat this stratum has a _definite_ lower limit. This favours the\nhypothesis of a molten shell.]\n\n[Footnote 26: I should add that while M. Faye ascribes solar spots to\nclouds formed within cyclones, we differ concerning the nature of the\ncloud. I have argued that it is formed by rarefaction, and consequent\nrefrigeration, of the metallic gases constituting the stratum in which\nthe cyclone exists. He argues that it is formed within the mass of\ncooled hydrogen drawn from the chromosphere into the vortex of the\ncyclone. Speaking of the cyclones he says:--\"Dans leur embouchure evasee\nils entraineront l'hydrogene froid de la chromosphere, produisant\npartout sur leur trajet vertical un abaissement notable de temperature\net une obscurite relative, due a l'opacite de l'hydrogene froid\nenglouti.\" (_Revue Scientifique_, 24 March 1883.) Considering the\nintense cold required to reduce hydrogen to the \"critical point,\" it is\na strong supposition that the motion given to it by fluid friction on\nentering the vortex of the cyclone, can produce a rotation, rarefaction,\nand cooling, great enough to produce precipitation in a region so\nintensely heated.]\n\n\n\n\nILLOGICAL GEOLOGY.\n\n    [_First published in_ The Universal Review _for July,_ 1859.]\n\n\nThat proclivity to generalization which is possessed in greater or less\ndegree by all minds, and without which, indeed, intelligence cannot\nexist, has unavoidable inconveniences. Through it alone can truth be\nreached; and yet it almost inevitably betrays into error. But for the\ntendency to predicate of every other case, that which has been found in\nthe observed cases, there could be no rational thinking; and yet by this\nindispensable tendency, men are perpetually led to found, on limited\nexperience, propositions which they wrongly assume to be universal or\nabsolute. In one sense, however, this can scarcely be regarded as an\nevil; for without premature generalizations the true generalization\nwould never be arrived at. If we waited till all the facts were\naccumulated before trying to formulate them, the vast unorganized mass\nwould be unmanageable. Only by provisional grouping can they be brought\ninto such order as to be dealt with; and this provisional grouping is\nbut another name for premature generalization. How uniformly men follow\nthis course, and how needful the errors are as steps to truth, is well\nillustrated in the history of Astronomy. The heavenly bodies move round\nthe Earth in circles, said the earliest observers: led partly by the\nappearances, and partly by their experiences of central motions in\nterrestrial objects, with which, as all circular, they classed the\ncelestial motions from lack of any alternative conception. Without this\nprovisional belief, wrong as it was, there could not have been that\ncomparison of positions which showed that the motions are not\nrepresentable by circles; and which led to the hypothesis of epicycles\nand eccentrics. Only by the aid of this hypothesis, equally untrue, but\ncapable of accounting more nearly for the appearances, and so of\ninducing more accurate observations--only thus did it become possible\nfor Copernicus to show that the heliocentric theory is more feasible\nthan the geocentric theory; or for Kepler to show that the planets move\nround the sun in ellipses. Yet again, without the aid of Kepler's more\nadvanced theory of the Solar system, Newton could not have established\nthat general law from which it follows, that the motion of a heavenly\nbody is not necessarily in an ellipse, but may be in any conic section.\nAnd lastly, it was only after the law of gravitation had been verified,\nthat it became possible to determine the actual courses of planets,\nsatellites, and comets; and to prove that, in consequence of\nperturbations, their orbits always deviate, more or less, from regular\ncurves. In these successive theories we may trace both the tendency men\nhave to leap from scanty data to wide generalizations, that are either\nuntrue or but partially true; and the necessity there is for such\ntransitional generalizations as steps to the final one.\n\nIn the progress of geological speculation, the same laws of thought are\ndisplayed. We have dogmas that were more than half false, passing\ncurrent for a time as universal truths. We have evidence collected in\nproof of these dogmas; by and by a colligation of facts in antagonism\nwith them; and eventually a consequent modification. In conformity with\nthis improved hypothesis, we have a better classification of facts; a\ngreater power of arranging and interpreting the new facts now rapidly\ngathered together; and further resulting corrections of hypothesis.\nBeing, as we are at present, in the midst of this process, it is not\npossible to give an adequate account of the development of geological\nscience as thus regarded: the earlier stages are alone known to us. Not\nonly, however, is it interesting to observe how the more advanced views\nnow received respecting the Earth's history, have been evolved out of\nthe crude views which preceded them; but we shall find it extremely\ninstructive to observe this. We shall see how greatly the old ideas\nstill sway both the general mind and the minds of geologists themselves.\nWe shall see how the kind of evidence that has in part abolished these\nold ideas, is still daily accumulating, and threatens to make other like\nrevolutions. In brief, we shall see whereabouts we are in the\nelaboration of a true theory of the Earth; and, seeing our whereabouts,\nshall be the better able to judge, among various conflicting opinions,\nwhich best conform to the ascertained direction of geological discovery.\n\nIt is needless here to enumerate the many speculations which were in\nearlier ages propounded by acute men--speculations some of which\ncontained portions of truth. Falling in unfit times, these speculations\ndid not germinate; and hence do not concern us. We have nothing to do\nwith ideas, however good, out of which no science grew; but only with\nthose which gave origin to the existing system of Geology. We therefore\nbegin with Werner.\n\nTaking for data the appearances of the Earth's crust in a narrow\ndistrict of Germany; observing the constant order of superposition of\nstrata, and their respective physical characters; Werner drew the\ninference that strata of like characters succeeded each other in like\norder over the entire surface of the Earth. And seeing, from the\nlaminated structure of many formations and the organic remains contained\nin others, that they were sedimentary; he further inferred that these\nuniversal strata had been in succession precipitated from a chaotic\nmenstruum which once covered our planet. Thus, on a very incomplete\nacquaintance with a thousandth part of the Earth's crust, he based a\nsweeping generalization applying to the whole of it. This Neptunist\nhypothesis, mark, borne out though it seemed to be by the most\nconspicuous surrounding facts, was quite untenable if analyzed. That a\nuniversal chaotic menstruum should deposit a series of numerous\nsharply-defined strata, differing from one another in composition, is\nincomprehensible. That the strata so deposited should contain the\nremains of plants and animals, which could not have lived under the\nsupposed conditions, is still more incomprehensible. Physically absurd,\nhowever, as was this hypothesis, it recognized, though under a distorted\nform, one of the great agencies of geological change--the action of\nwater. It served also to express the fact, that the formations of the\nEarth's crust stand in some kind of order. Further, it did a little\ntowards supplying a nomenclature, without which much progress was\nimpossible. Lastly, it furnished a standard with which successions of\nstrata in various regions could be compared, the differences noted, and\nthe actual sections tabulated. It was the first provisional\ngeneralization; and was useful, if not indispensable, as a step to truer\nones.\n\nFollowing this rude conception, which ascribed geological phenomena to\none agency, acting during one primeval epoch, there came a\ngreatly-improved conception, which ascribed them to two agencies, acting\nalternately during successive epochs. Hutton, perceiving that\nsedimentary deposits were still being formed at the bottom of the sea\nfrom the detritus carried down by rivers; perceiving, further, that the\nstrata of which the visible surface chiefly consists, bore marks of\nhaving been similarly formed out of pre-existing land; and inferring\nthat these strata could have become land only by upheaval after their\ndeposit; concluded that throughout an indefinite past, there had been\nperiodic convulsions, by which continents were raised, with intervening\neras of repose, during which such continents were worn down and\ntransformed into new marine strata, fated to be in their turns elevated\nabove the surface of the ocean. And finding that igneous action, to\nwhich sundry earlier geologists had ascribed basaltic rocks, was in\ncountless places a cause of disturbance, he taught that from it resulted\nthese periodic convulsions. In this theory we see:--first, that the\npreviously-recognized agency of water was conceived to act, not as by\nWerner, after a manner of which we have no experience, but after a\nmanner daily displayed to us; and secondly, that the igneous agency,\nbefore considered only as originating special formations, was recognized\nas a universal agency, but assumed to act in an unproved way. Werner's\nsole process Hutton developed from the catastrophic and inexplicable\ninto the uniform and explicable; while that antagonistic second process,\nof which he first adequately estimated the importance, was regarded by\nhim as a catastrophic one, and was not assimilated to known\nprocesses--not explained. We have here to note, however, that the facts\ncollected and provisionally arranged in conformity with Werner's theory,\nserved, after a time, to establish Hutton's more rational theory--in so\nfar, at least, as aqueous formations are concerned; while the doctrine\nof periodic subterranean convulsions, crudely as it was conceived by\nHutton, was a temporary generalization needful as a step towards the\ntheory of igneous action.\n\nSince Hutton's time, the development of geological thought has gone\nstill further in the same direction. These early sweeping doctrines have\nreceived additional qualifications. It has been discovered that more\nnumerous and more heterogeneous agencies have been at work, than was at\nfirst believed. The conception of igneous action has been rationalized,\nas the conception of aqueous action had previously been. The gratuitous\nassumption that vast elevations suddenly occurred after long intervals\nof quiescence, has grown into the consistent theory, that islands and\ncontinents are the accumulated results of successive small upheavals,\nlike those experienced in ordinary earthquakes. To speak more\nspecifically, we find, in the first place, that instead of assuming the\ndenudation produced by rain and rivers to be the sole means of wearing\ndown lands and producing their irregularities of surface, geologists now\nsee that denudation is only a part-cause of such irregularities; and\nfurther, that the new strata deposited at the bottom of the sea, are not\nthe products of river-sediment solely, but are in part due to the\nactions of waves and tidal currents on the coasts. In the second place,\nwe find that Hutton's conception of upheaval by subterranean forces, has\nnot only been modified by assimilating these subterranean forces to\nordinary earthquake-forces; but modern inquiries have shown that,\nbesides elevations of surface, subsidences are thus produced; that local\nupheavals, as well as the general upheavals which raise continents, come\nwithin the same category; and that all these changes are probably\nconsequent on the progressive collapse of the Earth's crust upon its\ncooling and contracting nucleus. In the third place, we find that beyond\nthese two great antagonistic agencies, modern Geology recognizes sundry\nminor ones: those of glaciers and icebergs, those of coral-polypes;\nthose of _Protozoa_ having siliceous or calcareous shells--each of which\nagencies, insignificant as it seems, is found capable of slowly working\nterrestrial changes of considerable magnitude. Thus, then, the recent\nprogress of Geology has been a still further departure from primitive\nconceptions. Instead of one catastrophic cause, once in universal\naction, as supposed by Werner--instead of one general continuous cause,\nantagonized at long intervals by a catastrophic cause, as taught by\nHutton; we now recognize several causes, all more or less general and\ncontinuous. We no longer resort to hypothetical agencies to explain the\nphenomena displayed by the Earth's crust; but we are day by day more\nclearly perceiving that these phenomena have arisen from forces like\nthose now at work, which have acted in all varieties of combination,\nthrough immeasurable periods of time.\n\n       *       *       *       *       *\n\nHaving thus briefly traced the evolution of geologic science, and noted\nits present form, let us go on to observe the way in which it is still\nswayed by the crude hypotheses it set out with; so that even now,\ndoctrines long since abandoned as untenable in theory, continue in\npractice to mould the ideas of geologists, and to foster sundry beliefs\nthat are logically indefensible. We shall see, both how those simple\nsweeping conceptions with which the science commenced, are those which\nevery student is apt at first to seize hold of, and how several\ninfluences conspire to maintain the twist thus resulting--how the\noriginal nomenclature of periods and formations necessarily keeps alive\nthe original implications; and how the need for arranging new data in\nsome order, results in their being thrust into the old classification,\nunless their incongruity with it is very glaring. A few facts will best\nprepare the way for criticism.\n\nUp to 1839 it was inferred, from their crystalline character, that the\nmetamorphic rocks of Anglesea were more ancient than any rocks of the\nadjacent main land; but it has since been shown that they are of the\nsame age with the slates and grits of Carnarvon and Merioneth. Again,\nslaty cleavage having been first found only in the lowest rocks, was\ntaken as an indication of the highest antiquity: whence resulted serious\nmistakes; for this mineral characteristic is now known to occur in the\nCarboniferous system. Once more, certain red conglomerates and grits on\nthe north-west coast of Scotland, long supposed from their lithological\naspect to belong to the Old Red Sandstone, are now identified with the\nLower Silurians. These are a few instances of the small trust to be\nplaced in mineral qualities, as evidence of the ages or relative\npositions of strata. From the recently-published third edition of\n_Siluria_, may be culled numerous facts of like implication. Sir R.\nMurchison considers it ascertained, that the siliceous Stiper stones of\nShropshire are the equivalents of the Tremadock slates of North Wales.\nJudged by their fossils, Bala slate and limestone are of the same age as\nthe Caradoc sandstone, lying forty miles off. In Radnorshire, the\nformation classed as upper Llandovery rock, is described at different\nspots, as \"sandstone or conglomerate,\" \"impure limestone,\" \"hard coarse\ngrits,\" \"siliceous grit\"--a considerable variation for so small an area\nas that of a county. Certain sandy beds on the left bank of the Towy,\nwhich Sir R. Murchison had, in his _Silurian System_, classed as Caradoc\nsandstone (evidently from their mineral characters), he now finds, from\ntheir fossils, belong to the Llandeilo formation. Nevertheless,\ninferences from mineral characters are still habitually drawn and\nreceived. Though _Siluria_, in common with other geological works,\nsupplies numerous proofs that rocks of the same age are often of\nwidely-different composition a few miles off, while rocks of\nwidely-different ages are often of similar composition; and though Sir\nR. Murchison shows us, as in the case just cited, that he has himself in\npast times been misled by trusting to lithological evidence; yet his\nreasoning all through _Siluria_, shows that he still thinks it natural\nto expect formations of the same age to be chemically similar, even in\nremote regions. For example, in treating of the Silurian rocks of South\nScotland, he says:--\"When traversing the tract between Dumfries and\nMoffat, in 1850, it occurred to me, that the dull reddish or purple\nsandstone and schist to the north of the former town, which so resembled\nthe bottom rocks of Longmynd, Llanberis, and St. David's, would prove to\nbe of the same age;\" and further on, he again insists upon the fact that\nthese strata \"are absolutely of the same composition as the bottom rocks\nof the Silurian region.\" On this unity of mineral character it is, that\nthis Scottish formation is concluded to be contemporaneous with the\nlowest formations in Wales; for the scanty paleontological evidence\nsuffices for neither proof nor disproof. Now, had there been a\ncontinuity of like strata in like order between Wales and Scotland,\nthere might have been little to criticize in this conclusion. But since\nSir R. Murchison himself admits, that in Westmoreland and Cumberland,\nsome members of the system \"assume a lithological aspect different from\nwhat they maintain in the Silurian and Welsh region,\" there seems no\nreason to expect mineralogical continuity in Scotland. Obviously,\ntherefore, the assumption that these Scottish formations are of the same\nage with the Longmynd of Shropshire, implies the latent belief that\ncertain mineral characters indicate certain eras. Far more striking\ninstances, however, of the influence of this latent belief remain to be\ngiven. Not in such comparatively near districts as the Scottish lowlands\nonly, does Sir R. Murchison expect a repetition of the Longmynd strata;\nbut in the Rhenish provinces, certain \"quartzose flagstones and grits,\nlike those of the Longmynd,\" are seemingly concluded to be of\ncontemporaneous origin, because of their likeness. \"Quartzites in\nroofing-slates with a greenish tinge that reminded us of the lower\nslates of Cumberland and Westmoreland,\" are evidently suspected to be of\nthe same age. In Russia, he remarks that the carboniferous limestones\n\"are overlaid along the western edge of the Ural chain by sandstones and\ngrits, which occupy much the same place in the general series as the\nmillstone grit of England;\" and in calling this group, as he does, the\n\"representative of the millstone grit,\" Sir R. Murchison clearly shows\nthat he thinks likeness of mineral composition some evidence of\nequivalence in time, even at that great distance. Nay, on the flanks of\nthe Andes and in the United States, such similarities are looked for,\nand considered as significant of certain ages. Not that Sir R. Murchison\ncontends theoretically for this relation between lithological character\nand date. For on the page from which we have just quoted (_Siluria_,\np. 387), he says, that \"whilst the soft Lower Silurian clays and sands\nof St. Petersburg have their equivalents in the hard schists and quartz\nrocks with gold veins in the heart of the Ural mountains, the equally\nsoft red and green Devonian marls of the Valdai Hills are represented on\nthe western flank of that chain by hard, contorted, and fractured\nlimestones.\" But these, and other such admissions, seem to go for\nlittle. While himself asserting that the Potsdam-sandstone of North\nAmerica, the Lingula-flags of England, and the alum-slates of\nScandinavia are of the same period--while fully aware that among the\nSilurian formations of Wales, there are oolitic strata like those of\nsecondary age; yet his reasoning is more or less coloured by the\nassumption, that formations of like qualities probably belong to the\nsame era. Is it not manifest, then, that the exploded hypothesis of\nWerner continues to influence geological speculation?\n\n\"But,\" it will perhaps be said, \"though individual strata are not\ncontinuous over large areas, yet systems of strata are. Though within a\nfew miles the same bed gradually passes from clay into sand, or thins\nout and disappears, yet the group of strata to which it belongs does not\ndo so; but maintains in remote regions the same relations to other\ngroups.\"\n\nThis is the generally-current belief. On this assumption the received\ngeological classifications appear to be framed. The Silurian system, the\nDevonian system, the Carboniferous system, etc., are set down in our\nbooks as groups of formations which everywhere succeed each other in a\ngiven order; and are severally everywhere of the same age. Though it may\nnot be asserted that these successive systems are universal; yet it\nseems to be tacitly assumed that they are. In North and South America,\nin Asia, in Australia, sets of strata are assimilated to one or other of\nthese groups; and their possession of certain mineral characters and a\ncertain order of superposition are among the reasons assigned for so\nassimilating them. Though, probably, no competent geologist would\ncontend that the European classification of strata is applicable to the\nglobe as a whole; yet most, if not all geologists, write as though it\nwere. Among readers of works on Geology, nine out of ten carry away the\nimpression that the divisions, Primary, Secondary and Tertiary, are of\nabsolute and uniform application; that these great divisions are\nseparable into subdivisions, each of which is definitely distinguishable\nfrom the rest, and is everywhere recognizable by its characters as such\nor such; and that in all parts of the Earth, these minor systems\nseverally began and ended at the same time. When they meet with the term\n\"Carboniferous era,\" they take for granted that it was an era\nuniversally carboniferous--that it was, what Hugh Miller indeed actually\ndescribes it, an era when the Earth bore a vegetation far more luxuriant\nthan it has since done; and were they in any of our colonies to meet\nwith a coal-bed, they would conclude that, as a matter of course, it was\nof the same age as the English coal-beds.\n\nNow this belief that geologic \"systems\" are universal, is no more\ntenable than the other. It is just as absurd when considered _a priori_;\nand it is equally inconsistent with the facts. Though some series of\nstrata classed together as Oolite, may range over a wider district than\nany one stratum of the series; yet we have but to ask what were the\ncircumstances under which it was deposited, to see that the Oolitic\nseries, like one of its individual strata, must be of local origin; and\nthat there is not likely to be anywhere else, a series which\ncorresponds, either in its characters or in its commencement and\ntermination. For the formation of such a series implies an area of\nsubsidence, in which its component beds were thrown down. Every area of\nsubsidence is necessarily limited; and to suppose that there exist\nelsewhere groups of beds completely answering to those known as Oolite,\nis to suppose that, in contemporaneous areas of subsidence, like\nprocesses were going on. There is no reason to suppose this; but good\nreason to suppose the reverse. That in contemporaneous areas of\nsubsidence throughout the globe, the conditions would cause the\nformation of Oolite, is an assumption which no modern geologist would\nopenly make. He would say that the equivalent series of beds found\nelsewhere, would probably be of dissimilar mineral character. Moreover,\nin these contemporaneous areas of subsidence, the processes going on\nwould not only be different in kind; but in no two cases would they be\nlikely to agree in their commencements and terminations. The\nprobabilities are greatly against separate portions of the Earth's\nsurface beginning to subside at the same time, and ceasing to subside at\nthe same time--a coincidence which alone could produce equivalent groups\nof strata. Subsidences in different places begin and end with utter\nirregularity; and hence the groups of strata thrown down in them can but\nrarely correspond. Measured against each other in time, their limits\nmust disagree. On turning to the evidence, we find that it daily tends\nmore and more to justify these _a priori_ positions. Take, as an\nexample, the Old Red Sandstone system. In the north of England this is\nrepresented by a single stratum of conglomerate. In Herefordshire,\nWorcestershire, and Shropshire, it expands into a series of strata from\neight to ten thousand feet thick, made up of conglomerates, red, green,\nand white sandstones, red, green, and spotted marls, and concretionary\nlimestones. To the south-west, as between Caermarthen and Pembroke,\nthese Old Red Sandstone strata exhibit considerable lithological\nchanges; on the other side of the Bristol Channel, they display further\nchanges in mineral characters; while in South Devon and Cornwall, the\nequivalent strata, consisting chiefly of slates, schists, and\nlimestones, are so wholly different, that they were for a long time\nclassed as Silurian. When we thus see that in certain directions the\nwhole group of deposits thins out, and that its mineral characters\nchange within moderate distances; does it not become clear that the\nwhole group of deposits was a local one? And when we find, in other\nregions, formations analogous to these Old Red Sandstone or Devonian\nformations, is it certain--is it even probable--that they severally\nbegan and ended at the same time with them? Should it not require\noverwhelming evidence to make us believe as much?\n\nYet so strongly is geological speculation swayed by the tendency to\nregard the phenomena as general instead of local, that even those most\non their guard against it seem unable to escape its influence. At page\n158 of his _Principles of Geology_, Sir Charles Lyell says:--\n\n     \"A group of red marl and red sandstone, containing salt and gypsum,\n     being interposed in England between the Lias and the Coal, all\n     other red marls and sandstones, associated some of them with salt,\n     and others with gypsum, and occurring not only in different parts\n     of Europe, but in North America, Peru, India, the salt deserts of\n     Asia, those of Africa--in a word, in every quarter of the globe,\n     were referred to one and the same period.... It was in vain to urge\n     as an objection the improbability of the hypothesis which implies\n     that all the moving waters on the globe were once simultaneously\n     charged with sediment of a red colour. But the rashness of\n     pretending to identify, in age, all the red sandstones and marls in\n     question, has at length been sufficiently exposed, by the discovery\n     that, even in Europe, they belong decidedly to many different\n     epochs.\"\n\nNevertheless, while in this and many kindred passages Sir C. Lyell\nprotests against the bias here illustrated, he seems himself not\ncompletely free from it. Though he utterly rejects the old hypothesis\nthat all over the Earth the same continuous strata lie one upon another\nin regular order, like the coats of an onion, he still writes as though\ngeologic \"systems\" do thus succeed each other. A reader of his _Manual_\nwould certainly suppose him to believe, that the Primary epoch ended,\nand the secondary epoch began, all over the world at the same time--that\nthese terms really correspond to distinct universal eras. When he\nassumes, as he does, that the division between Cambrian and Lower\nSilurian in America, answers chronologically to the division between\nCambrian and Lower Silurian in Wales--when he takes for granted that\nthe partings of Lower from Middle Silurian, and of Middle Silurian from\nUpper, in the one region, are of the same dates as the like partings in\nthe other region; does it not seem that he believes geologic \"systems\"\nto be universal, in the sense that their separations were in all places\ncontemporaneous? Though he would, doubtless, disown this as an article\nof faith, is not his thinking unconsciously influenced by it? Must we\nnot say that, though the onion-coat hypothesis is dead, its spirit is\ntraceable, under a transcendental form, even in the conclusions of its\nantagonists?\n\n       *       *       *       *       *\n\nLet us now consider another leading geological doctrine,--the doctrine\nthat strata of the same age contain like fossils; and that, therefore,\nthe age and relative position of any stratum may be known by its\nfossils. While the theory that strata of like mineral characters were\neverywhere deposited simultaneously, has been ostensibly abandoned,\nthere has been accepted the theory that in each geologic epoch similar\nplants and animals existed everywhere; and that, therefore, the epoch to\nwhich any formation belongs may be known by the organic remains\ncontained in the formation. Though, perhaps, no leading geologist would\nopenly commit himself to an unqualified assertion of this theory, yet it\nis tacitly assumed in current geological reasoning.\n\nThis theory, however, is scarcely more tenable than the other. It cannot\nbe concluded with any certainty, that formations in which similar\norganic remains are found, were of contemporaneous origin; nor can it be\nsafely concluded that strata containing different organic remains are of\ndifferent ages. To most readers these will be startling propositions;\nbut they are fully admitted by the highest authorities. Sir Charles\nLyell confesses that the test of organic remains must be used \"under\nvery much the same restrictions as the test of mineral composition.\" Sir\nHenry de la Beche, who variously illustrates this truth, remarks on the\ngreat incongruity there must be between the fossils of our carboniferous\nrocks and those of the marine strata deposited at the same period. But\nthough, in the abstract, the danger of basing positive conclusions on\nevidence derived from fossils, is recognized; yet, in the concrete, this\ndanger is generally disregarded. The established convictions respecting\nthe ages of strata, have been formed in spite of it; and by some\ngeologists it seems altogether ignored. Throughout his _Siluria_, Sir R.\nMurchison habitually assumes that the same, or kindred, species, lived\nin all parts of the Earth at the same time. In Russia, in Bohemia, in\nthe United States, in South America, strata are classed as belonging to\nthis or that part of the Silurian system, because of the similar fossils\ncontained in them--are concluded to be everywhere contemporaneous if\nthey enclose a proportion of identical or allied forms. In Russia the\nrelative position of a stratum is inferred from the fact that, along\nwith some Wenlock forms, it yields the _Pentamerus oblongus_. Certain\ncrustaceans called _Eurypteri_, being characteristic of the Upper Ludlow\nrock, it is remarked that \"large Eurypteri occur in a so-called black\ngrey-wacke slate in Westmoreland, in Oneida County, New York, which will\nprobably be found to be on the parallel of the Upper Ludlow rock:\" in\nwhich word \"probably,\" we see both how dominant is this belief of\nuniversal distribution of similar creatures at the same period, and how\napt this belief is to make its own proof, by raising the expectation\nthat the ages are identical when the forms are alike. Besides thus\ninterpreting the formations of Russia, England, and America, Sir R.\nMurchison thus interprets those of the antipodes. Fossils from Victoria\nColony, he agrees with the Government-surveyor in classing as of Lower\nSilurian or Llandovery age: that is, he takes for granted that when\ncertain crustaceans and mollusks were living in Wales, certain similar\ncrustaceans and mollusks were living in Australia. Yet the\nimprobability of this assumption may be readily shown from Sir R.\nMurchison's own facts. If, as he points out, the fossil crustaceans of\nthe uppermost Silurian rocks in Lanarkshire are, \"with one doubtful\nexception,\" all \"distinct from any of the forms known on the same\nhorizon in England;\" how can it be fairly presumed that the forms\nexisting on the other side of the Earth during the Silurian period, were\nnearly allied to those existing here? Not only, indeed, do Sir R.\nMurchison's conclusions tacitly assume this doctrine of universal\ndistribution, but he distinctly enunciates it. \"The mere presence of a\ngraptolite,\" he says, \"will at once decide that the enclosing rock is\nSilurian;\" and he says this, notwithstanding repeated warnings against\nsuch generalizations. During the progress of Geology, it has over and\nover again happened that a particular fossil, long considered\ncharacteristic of a particular formation, has been afterwards discovered\nin other formations. Until some twelve years ago, Goniatites had not\nbeen found lower than the Devonian rocks; but now, in Bohemia, they have\nbeen found in rocks classed as Silurian. Quite recently, the\n_Orthoceras_, previously supposed to be a type exclusively palaeozoic,\nhas been detected along with mesozoic Ammonites and Belemnites. Yet\nhosts of such experiences fail to extinguish the assumption, that the\nage of a stratum may be determined by the occurrence in it of a single\nfossil form. Nay, this assumption survives evidence of even a still more\ndestructive kind. Referring to the Silurian system in Western Ireland,\nSir R. Murchison says, \"in the beds near Maam, Professor Nicol and\nmyself collected remains, some of which would be considered Lower, and\nothers Upper, Silurian;\" and he then names sundry fossils which, in\nEngland, belong to the summit of the Ludlow rocks, or highest Silurian\nstrata; \"some, which elsewhere are known only in rocks of Llandovery\nage\"--that is, of middle Silurian age; and some, only before known in\nLower Silurian strata, not far above the most ancient fossiliferous\nbeds. Now what do these facts prove? Clearly, they prove that species\nwhich in Wales are separated by strata more than twenty thousand feet\ndeep, and therefore seem to belong to periods far more remote from each\nother, were really co-existent. They prove that the mollusks and\ncrinoids held to be characteristic of early Silurian strata, and\nsupposed to have become extinct long before the mollusks and crinoids of\nthe later Silurian strata came into existence, were really flourishing\nat the same time with these last; and that these last possibly date back\nto as early a period as the first. They prove that not only the mineral\ncharacters of sedimentary formations, but also the collections of\norganic forms they contain, depend, to a great extent, on local\ncircumstances. They prove that the fossils met with in any series of\nstrata, cannot be taken as representing anything like the whole Flora\nand Fauna of the period they belong to. In brief, they throw great doubt\nupon numerous geological generalizations.\n\nNotwithstanding facts like these, and notwithstanding his avowed opinion\nthat the test of organic remains must be used \"under very much the same\nrestrictions as the test of mineral composition,\" Sir Charles Lyell,\ntoo, considers sundry positive conclusions to be justified by this test:\neven where the community of fossils is slight and the distance great.\nHaving decided that in various places in Europe, middle Eocene strata\nare distinguished by Nummulites; he infers, without any other assigned\nevidence, that wherever Nummulites are found--in Morocco, Algeria,\nEgypt, in Persia, Scinde, Cutch, Eastern Bengal, and the frontiers of\nChina--the containing formation is Middle Eocene. And from this\ninference he draws the following important corollary:--\n\n     \"When we have once arrived at the conviction that the nummulitic\n     formation occupies a middle place in the Eocene series, we are\n     struck with the comparatively modern date to which some of the\n     greatest revolutions in the physical geography of Europe, Asia, and\n     northern Africa must be referred. All the mountain chains, such as\n     the Alps, Pyrenees, Carpathians, and Himalayas, into the\n     composition of whose central and loftiest parts the nummulitic\n     strata enter bodily, could have had no existence till after the\n     Middle Eocene period.\"--_Manual_, p. 232.\n\nA still more marked case follows on the next page. Because a certain bed\nat Claiborne in Alabama, which contains \"_four hundred_ species of\nmarine shells,\" includes among them the _Cardita planicosta_, \"and _some\nothers_ identical with European species, or very nearly allied to them,\"\nSir C. Lyell says it is \"highly probable the Claiborne beds agree in age\nwith the central or Bracklesham group of England.\" When we find\ncontemporaneity alleged on the strength of a community no greater than\nthat which sometimes exists between strata of widely-different ages in\nthe same country, it seems as though the above-quoted caution had been\nforgotten. It appears to be assumed for the occasion, that species which\nhad a wide range in space had a narrow range in time; which is the\nreverse of the fact. The tendency to systematize overrides the evidence,\nand thrusts Nature into a formula too rigid to fit her endless variety.\n\n\"But,\" it may be urged, \"surely, when in different places the order of\nsuperposition, the mineral characters, and the fossils, agree, it may\nsafely be concluded that the formations thus corresponding date back to\nthe same time. If, for example, the United States display a succession\nof Silurian, Devonian, and Carboniferous systems, lithologically similar\nto those known here by those names, and characterized by like fossils,\nit is a fair inference that these groups of strata were severally being\ndeposited in America while their equivalents were being deposited here.\"\n\nOn this position, which seems a strong one, we have, in the first place,\nto remark, that the evidence of correspondence is always more or less\nsuspicious. We have already adverted to the several \"idols\"--if we may\nuse Bacon's metaphor--to which geologists unconsciously sacrifice, when\ninterpreting the structures of unexplored regions. Carrying with them\nthe classification of strata existing in Europe, and assuming that\ngroups of strata in other parts of the world must answer to some of the\ngroups of strata known here, they are necessarily prone to assert\nparallelism on insufficient evidence. They scarcely entertain the\nprevious question, whether the formations they are examining have or\nhave not any European equivalents; but the question is--with which of\nthe European series shall they be classed?--with which do they most\nagree?--from which do they differ least? And this being the mode of\ninquiry, there is apt to result great laxity of interpretation. How lax\nthe interpretation really is, may be readily shown. When strata are\ndiscontinuous, as between Europe and America, no evidence can be derived\nfrom the order of superposition, apart from mineral characters and\norganic remains; for, unless strata can be continuously traced, mineral\ncharacters and organic remains afford the only means of classing them as\nsuch or such. As to the test of mineral characters, we have seen that it\nis almost worthless; and no modern geologist would dare to say it should\nbe relied on. If the Old Red Sandstone series in mid-England, differs\nwholly in lithological aspect from the equivalent series in South Devon,\nit is clear that similarities of texture and composition cannot justify\nus in classing a system of strata in another quarter of the globe with\nsome European system. The test of fossils is the only one that remains;\nand with how little strictness this test is applied, one case will show.\nOf forty-six species of British Devonian corals, only six occur in\nAmerica; and this, notwithstanding the wide range which the _Anthozoa_\nare known to have. Similarly of the _Mollusca_ and _Crinoidea_, it\nappears that, while there are sundry genera found in America which are\nfound here, there are scarcely any of the same species. And Sir Charles\nLyell admits that \"the difficulty of deciding on the exact parallelism\nof the New York subdivisions, as above enumerated, with the members of\nthe European Devonian, is very great, so few are the species in common.\"\nYet it is on the strength of community of fossils, that the whole\nDevonian series of the United States is assumed to be contemporaneous\nwith the whole Devonian series of England. And it is partly on the\nground that the Devonian of the United States corresponds in time with\nour own Devonian, that Sir Charles Lyell concludes the superjacent\ncoal-measures of the two countries to be of the same age. Is it not,\nthen, as we said, that the evidence in these cases is very suspicious?\nShould it be replied, as it may fairly be, that this correspondence from\nwhich the synchronism of distant formations is inferred, is not a\ncorrespondence between particular species or particular genera, but\nbetween the general characters of the contained assemblages of\nfossils--between the _facies_ of the two Faunas; the rejoinder is, that\nthough such correspondence is a stronger evidence of synchronism it is\nstill an insufficient one. To infer synchronism from such\ncorrespondence, involves the postulate that throughout each geologic era\nthere has habitually existed a recognizable similarity between the\ngroups of organic forms inhabiting all the different parts of the Earth;\nand that the causes which have in one part of the Earth changed the\norganic forms into those which characterize the next era, have\nsimultaneously acted in all other parts of the Earth, in such ways as to\nproduce parallel changes of their organic forms. Now this is not only a\nlarge assumption to make; but it is an assumption contrary to\nprobability. The probability is, that the causes which have changed\nFaunas have been local rather than universal; that hence while the\nFaunas of some regions have been rapidly changing, those of others have\nbeen almost quiescent; and that when those of others have been changed,\nit has been, not in such ways as to maintain parallelism, but in such\nways as to produce divergence.\n\nEven supposing, however, that districts some hundreds of miles apart,\nfurnished groups of strata which completely agreed in their order of\nsuperposition, their mineral characters, and their fossils, we should\nstill have inadequate proof of contemporaneity. For there are\nconditions, very likely to occur, under which such groups might differ\nwidely in age. If there be a continent of which the strata crop out on\nthe surface obliquely to the line of coast--running, say,\nwest-north-west, while the coast runs east and west--it is clear that\neach group of strata will crop out on the beach at a particular part of\nthe coast; that further west the next group of strata will crop out on\nthe beach; and so continuously. As the localization of marine plants and\nanimals, is in a considerable degree determined by the natures of the\nrocks and their detritus, it follows that each part of this coast will\nhave its more or less distinct Flora and Fauna. What now must result\nfrom the action of the waves in the course of a geologic epoch? As the\nsea makes slow inroads on the land, the place at which each group of\nstrata crops out on the beach will gradually move towards the west: its\ndistinctive fish, mollusks, crustaceans, and sea-weeds, migrating with\nit. Further, the detritus of each of these groups of strata will, as the\npoint of outcrop moves westwards, be deposited over the detritus of the\ngroup in advance of it. And the consequence of these actions, carried on\nfor one of those enormous periods which a geologic change takes, will be\nthat, corresponding to each eastern stratum, there will arise a stratum\nfar to the west, which, though occupying the same position relatively to\nother beds, formed of like materials, and containing like fossils, will\nyet be perhaps a million years later in date.\n\n       *       *       *       *       *\n\nBut the illegitimacy, or at any rate the great doubtfulness, of many\ncurrent geological inferences, is best seen when we contemplate\nterrestrial changes now going on; and ask how far such inferences are\ncountenanced by them. If we carry out rigorously the modern method of\ninterpreting geological phenomena, which Sir Charles Lyell has done so\nmuch to establish--that of referring them to causes like those at\npresent in action--we cannot fail to see how improbable are sundry of\nthe received conclusions.\n\nAlong each shore which is being worn away by the waves, there are being\nformed mud, sand, and pebbles. This detritus has, in each locality, a\nmore or less special character; determined by the nature of the strata\ndestroyed. In the English Channel it is not the same as in the Irish\nChannel; on the east coast of Ireland it is not the same as on the west\ncoast; and so throughout. At the mouth of each great river, there is\nbeing deposited sediment differing more or less from that deposited at\nthe mouths of other rivers in colour and quality; forming strata which\nare here red, there yellow, and elsewhere brown, grey, or dirty white.\nBesides which various formations, going on in deltas and along shores,\nthere are some much wider, and still more strongly contrasted,\nformations. At the bottom of the AEgean Sea, there is accumulating a bed\nof Pteropod shells, which will eventually, no doubt, become a calcareous\nrock. For some hundreds of thousands of square miles, the ocean-bed\nbetween Great Britain and North America, is being covered with a stratum\nof chalk; and over large areas in the Pacific, there are going on\ndeposits of coralline limestone. Thus, there are at this moment being\nproduced in different places multitudinous strata differing from one\nanother in lithological characters. Name at random any part of the\nsea-bottom, and ask whether the deposit there taking place is like the\ndeposit taking place at some distant part of the sea-bottom, and the\nalmost-certainly correct answer will be--No. The chances are not in\nfavour of similarity, but against it--many to one against it.\n\nIn the order of superposition of strata there is being established a\nlike variety. Each region of the Earth's surface has its special history\nof elevations, subsidences, periods of rest: and this history in no case\nfits chronologically with the history of any other portion. River\ndeltas are now being thrown down on formations of different ages: some\nvery ancient, some quite modern. While here there has been deposited a\nseries of beds many hundreds of feet thick, there has elsewhere been\ndeposited but a single bed of fine mud. While one region of the Earth's\ncrust, continuing for a vast epoch above the surface of the ocean, bears\nrecord of no changes save those resulting from denudation; another\nregion of the Earth's crust gives proof of sundry changes of level, with\ntheir several resulting masses of stratified detritus. If anything is to\nbe judged from current processes, we must infer, not only that\neverywhere the succession of sedimentary formations differs more or less\nfrom the succession elsewhere; but also that in each place, there exist\ngroups of strata to which many other places have no equivalents.\n\nWith respect to the organic bodies imbedded in formations now in\nprogress, a like truth is equally manifest, if not more manifest. Even\nalong the same coast, within moderate distances, the forms of life\ndiffer very considerably; and they differ much more on coasts that are\nremote from one another. Again, dissimilar creatures which are living\ntogether near the same shore, do not leave their remains in the same\nbeds of sediment. For instance, at the bottom of the Adriatic, where the\nprevailing currents cause the deposits to be here of mud, and there of\ncalcareous matter, it is proved that different species of co-existing\nshells are being buried in these respective formations. On our own\ncoasts, the marine remains found a few miles from shore, in banks where\nfish congregate, are different from those found close to the shore,\nwhere littoral species flourish. A large proportion of aquatic creatures\nhave structures which do not admit of fossilization; while of the rest,\nthe great majority are destroyed, when dead, by various kinds of\nscavengers. So that no one deposit near our shores can contain anything\nlike a true representation of the Fauna of the surrounding sea; much\nless of the co-existing Faunas of other seas in the same latitude; and\nstill less of the Faunas of seas in distant latitudes. Were it not that\nthe assertion seems needful, it would be almost absurd to say, that the\norganic remains now being buried in the Dogger Bank, can tell us next to\nnothing about the fish, crustaceans, mollusks, and corals, which are\nbeing buried in the Bay of Bengal. Still stronger is the argument in the\ncase of terrestrial life. With more numerous and greater contrasts\nbetween the types inhabiting one continent and those inhabiting another,\nthere is a far more imperfect registry of them. Schouw marks out on the\nEarth more than twenty botanical regions, occupied by groups of forms so\ndistinct, that, if fossilized, geologists would scarcely be disposed to\nrefer them all to the same period. Of Faunas, the Arctic differs from\nthe Temperate; the Temperate from the Tropical; and the South Temperate\nfrom the North Temperate. Nay, in the South Temperate Zone itself, the\ntwo regions of South Africa and South America are unlike in their\nmammals, birds, reptiles, fishes, mollusks, insects. The shells and\nbones now lying at the bottoms of lakes and estuaries in these several\nregions, have certainly not that similarity which is usually looked for\nin those of contemporaneous strata; and the recent forms exhumed in any\none of these regions would very untruly represent the present Flora and\nFauna of the Earth. In conformity with the current style of geological\nreasoning, an exhaustive examination of deposits in the Arctic circle,\nmight be held to prove that though at this period there were sundry\nmammals existing, there were no reptiles; while the absence of mammals\nin the deposits of the Galapagos Archipelago, where there are plenty of\nreptiles, might be held to prove the reverse. And at the same time, from\nthe formations extending for two thousand miles along the great\nbarrier-reef of Australia--formations in which are imbedded nothing but\ncorals, echinoderms, mollusks, crustaceans, and fish, along with an\noccasional turtle, or bird, or cetacean--it might be inferred that there\nlived in our epoch neither terrestrial reptiles, nor terrestrial\nmammals. The mention of Australia, indeed, suggests an illustration\nwhich, even alone, would amply prove our case. The Fauna of this region\ndiffers widely from any that is found elsewhere. On land, all the\nindigenous mammals, except bats, belong to the lowest, or implacental\ndivision; and the insects are singularly different from those found\nelsewhere. The surrounding seas contain numerous forms which are more or\nless strange; and among the fish there exists a species of shark, which\nis the only living representative of a genus that flourished in early\ngeologic epochs. If, now, the modern fossiliferous deposits of Australia\nwere to be examined by one ignorant of the existing Australian Fauna;\nand if he were to reason in the usual manner; he would be very unlikely\nto class these deposits with those of the present time. How, then, can\nwe place confidence in the tacit assumption that certain formations in\nremote parts of the Earth are referable to the same period, because the\norganic remains contained in them display a certain community of\ncharacter? or that certain others are referable to different periods,\nbecause the _facies_ of their Faunas are different?\n\n\"But,\" it will be replied, \"in past eras the same, or similar, organic\nforms were more widely distributed than now.\" It may be so; but the\nevidence adduced by no means proves it. The argument by which this\nconclusion is reached, runs a risk of being quoted as an example of\nreasoning in a circle. As already pointed out, between formations in\nremote regions the accepted test of equivalence is community of fossils.\nIf, then, the contemporaneity of remote formations is concluded from the\nlikeness of their fossils; how can it be said that similar plants and\nanimals were once more widely distributed, because they are found in\ncontemporaneous strata in remote regions? Is not the fallacy manifest?\nEven supposing there were no such fatal objection as this, the evidence\ncommonly assigned would still be insufficient. For we must bear in mind\nthat the community of organic remains usually thought sufficient proof\nof correspondence in time, is a very imperfect community. When the\ncompared sedimentary beds are far apart, it is scarcely expected that\nthere will be many species common to the two: it is enough if there be\ndiscovered a considerable number of common genera. Now had it been\nproved that throughout geologic time, each genus lived but for a short\nperiod--a period measured by a single group of strata--something might\nbe inferred. But what if we learn that many of the same genera continued\nto exist throughout enormous epochs, measured by several vast systems of\nstrata? \"Among molluscs, the genera _Avicula_, _Modiola_, _Terebratula_,\n_Lingula_, and _Orbicula_, are found from the Silurian rocks upwards to\nthe present day.\" If, then, between the lowest fossiliferous formations\nand the most recent, there exists this degree of community; must we not\ninfer that there will probably often exist a great degree of community\nbetween strata that are far from contemporaneous?\n\nThus the reasoning from which it is concluded that similar organic forms\nwere once more widely spread than now, is doubly fallacious; and,\nconsequently, the classifications of foreign strata based on the\nconclusion are untrustworthy. Judging from the present distribution of\nlife, we cannot expect to find similar remains in geographically remote\nstrata of the same age; and where, between the fossils of geographically\nremote strata, we do find much similarity, it is probably due rather to\nlikeness of conditions than to contemporaneity. If from causes and\neffects such as we now witness, we reason back to the causes and effects\nof past epochs, we discover inadequate warrant for sundry of the\nreceived doctrines. Seeing, as we do, that in large areas of the Pacific\nthis is a period characterized by abundance of corals; that in the North\nAtlantic it is a period in which a great chalk-deposit is being formed;\nand that in the valley of the Mississippi it is a period of new\ncoal-basins--seeing also, as we do, that in one extensive continent this\nis peculiarly an era of implacental mammals, and that in another\nextensive continent it is peculiarly an era of placental mammals; we\nhave good reason to hesitate before accepting these sweeping\ngeneralizations which are based on a cursory examination of strata\noccupying but a tenth part of the Earth's surface.\n\n       *       *       *       *       *\n\nAt the outset, this article was to have been a review of the works of\nHugh Miller; but it has grown into something much more general.\nNevertheless, the remaining two doctrines which we propose to criticize,\nmay conveniently be treated in connexion with his name, as that of one\nwho fully committed himself to them. And first, a few words respecting\nhis position.\n\nThat he was a man whose life was one of meritorious achievement, every\none knows. That he was a diligent and successful working geologist,\nscarcely needs saying. That with indomitable perseverance he struggled\nup from obscurity to a place in the world of literature and science,\nshows him to have been highly endowed in character and intelligence. And\nthat he had a remarkable power of presenting his facts and arguments in\nan attractive form, a glance at any of his books will quickly prove. By\nall means, let us respect him as a man of activity and sagacity, joined\nwith a large amount of poetry. But while saying this we must add, that\nhis reputation stands by no means so high in the scientific world as in\nthe world at large. Partly from the fact that our Scotch neighbours are\nin the habit of blowing the trumpet rather loudly before their\nnotabilities--partly because the charming style in which his books are\nwritten has gained him a large circle of readers--partly, perhaps,\nthrough a praiseworthy sympathy with him as a self-made man; Hugh Miller\nhas met with an amount of applause which, little as we wish to diminish\nit, must not be allowed to blind the public to his defects as a man of\nscience. The truth is, he was so far committed to a foregone conclusion,\nthat he could not become a philosophical geologist. He might be aptly\ndescribed as a theologian studying geology. The dominant idea with which\nhe wrote, may be seen in the titles of two of his books--_Footprints of\nthe Creator_,--_The Testimony of the Rocks_. Regarding geological facts\nas evidence for or against certain religious conclusions, it was\nscarcely possible for him to deal with geological facts impartially. His\nruling aim was to disprove the Development Hypothesis, the assumed\nimplications of which were repugnant to him; and in proportion to the\nstrength of his feeling, was the one-sidedness of his reasoning. He\nadmitted that \"God might as certainly have _originated_ the species by a\nlaw of development, as he _maintains_ it by a law of development;--the\nexistence of a First Great Cause is as perfectly compatible with the one\nscheme as with the other.\" Nevertheless, he considered the hypothesis at\nvariance with Christianity; and therefore combated with it. He\napparently overlooked the fact, that the doctrines of geology in\ngeneral, as held by himself, had been rejected by many on similar\ngrounds; and that he had himself been repeatedly attacked for his\nanti-Christian teachings. He seems not to have perceived that, just as\nhis antagonists were wrong in condemning as irreligious, theories which\nhe saw were not irreligious; so might he be wrong in condemning, on like\ngrounds, the Theory of Evolution. In brief, he fell short of that\nhighest faith which knows that all truths must harmonize; and which is,\ntherefore, content trustfully to follow the evidence whithersoever it\nleads.\n\nOf course it is impossible to criticize his works without entering on\nthis great question to which he chiefly devoted himself. The two\nremaining doctrines to be here discussed, bear directly on this\nquestion; and, as above said, we propose to treat them in connexion with\nHugh Miller's name, because, throughout his reasonings, he assumes\ntheir truth. Let it not be supposed, however, that we shall aim to\nprove what he has aimed to disprove. While we purpose showing that his\ngeological arguments against the Development Hypothesis are based on\ninvalid assumptions; we do not purpose showing that the geological\narguments urged in support of it are based on valid assumptions. We hope\nto make it apparent that the geological evidence at present obtained, is\ninsufficient for either side; further, that there seems little\nprobability that sufficient evidence will ever be obtained; and that if\nthe question is eventually decided, it must be decided on other than\ngeological grounds.\n\n       *       *       *       *       *\n\nThe first of the current doctrines to which we have just referred, is,\nthat there occur in the serial records of former life on our planet, two\ngreat blanks; whence it is inferred that, on at least two occasions, the\npreviously existing inhabitants of the Earth were almost wholly\ndestroyed, and a different class of inhabitants created. Comparing the\ngeneral life on the Earth to a thread, Hugh Miller says:--\n\n     \"It is continuous from the present time up to the commencement of\n     the Tertiary period; and then so abrupt a break occurs, that, with\n     the exception of the microscopic diatomaceae, to which I last\n     evening referred, and of one shell and one coral, not a single\n     species crossed the gap. On its farther or remoter side, however,\n     where the Secondary division closes, the intermingling of species\n     again begins, and runs on till the commencement of this great\n     Secondary division; and then, just where the Palaeozoic division\n     closes, we find another abrupt break, crossed, if crossed at\n     all,--for there still exists some doubt on the subject,--by but two\n     species of plant.\"\n\nThese breaks are supposed to imply actual new creations on the surface\nof our planet--supposed not by Hugh Miller only, but by the majority of\ngeologists. And the terms Palaeozoic, Mesozoic, and Cainozoic, are used\nto indicate these three successive systems of life. It is true that some\naccept this belief with caution; knowing how geologic research has been\nall along tending to fill up what were once thought wide gaps. Sir\nCharles Lyell points out that \"the hiatus which exists in Great Britain\nbetween the fossils of the Lias and those of the Magnesian Limestone,\nis supplied in Germany by the rich fauna and flora of the Muschelkalk,\nKeuper, and Bunter Sandstein, which we know to be of a date precisely\nintermediate.\" Again he remarks that \"until lately the fossils of the\ncoal-measures were separated from those of the antecedent Silurian group\nby a very abrupt and decided line of demarcation; but recent discoveries\nhave brought to light in Devonshire, Belgium, the Eifel, and Westphalia,\nthe remains of a fauna of an intervening period.\" And once more, he\nsays, \"we have also in like manner had some success of late years in\ndiminishing the hiatus which still separates the Cretaceous and Eocene\nperiods in Europe.\" To which let us add that, since Hugh Miller penned\nthe passage above quoted, the second of the great gaps he refers to has\nbeen very considerably narrowed by the discovery of strata containing\nPalaeozoic genera and Mesozoic genera intermingled. Nevertheless, the\noccurrence of two great revolutions in the Earth's Flora and Fauna\nappears still to be held by many; and geologic nomenclature habitually\nassumes it.\n\nBefore seeking a solution of the problem thus raised, let us glance at\nthe several minor causes which produce breaks in the geological\nsuccession of organic forms; taking first, the more general ones which\nmodify climate, and, therefore, the distribution of life. Among these\nmay be noted one which has not, we believe, been named by writers on the\nsubject. We mean that resulting from a certain slow astronomic rhythm,\nby which the northern and southern hemispheres are alternately subject\nto greater extremes of temperature. In consequence of the slight\nellipticity of its orbit, the Earth's distance from the sun varies to\nthe extent of some 3,000,000 of miles. At present, the aphelion occurs\nat the time of our northern summer; and the perihelion during the summer\nof the southern hemisphere. In consequence, however, of that slow\nmovement of the Earth's axis which produces the precession of the\nequinoxes, this state of things will in time be reversed: the Earth\nwill be nearest to the sun during the summer of the northern hemisphere,\nand furthest from it during the southern summer or northern winter. The\nperiod required to complete the slow movement producing these changes,\nis nearly 26,000 years; and were there no modifying process, the two\nhemispheres would alternately experience this coincidence of summer with\nrelative nearness to the sun, during a period of 13,000 years. But there\nis also a still slower change in the direction of the axis major of the\nEarth's orbit; from which it results that the alternation we have\ndescribed is completed in about 21,000 years. That is to say, if at a\ngiven time the Earth is nearest to the sun at our mid-summer, and\nfurthest from the sun at our mid-winter; then, in 10,500 years\nafterwards, it will be furthest from the sun at our mid-summer, and\nnearest at our mid-winter. Now the difference between the distances from\nthe sun at the two extremes of this alternation, amounts to\none-thirtieth; and hence, the difference between the quantities of heat\nreceived from the sun on a summer's day under these opposite conditions\namounts to one-fifteenth. Estimating this, not with reference to the\nzero of our thermometers, but with reference to the temperature of the\ncelestial spaces, Sir John Herschel calculates \"23 deg. Fahrenheit, as the\nleast variation of temperature under such circumstances which can\nreasonably be attributed to the actual variation of the sun's distance.\"\nThus, then, each hemisphere has at a certain epoch, a short summer of\nextreme heat, followed by a long and very cold winter. Through the slow\nchange in the direction of the Earth's axis, these extremes are\ngradually mitigated. And at the end of 10,500 years, there is reached\nthe opposite state--a long and moderate summer, with a short and mild\nwinter. At present, in consequence of the predominance of sea in the\nsouthern hemisphere, the extremes to which its astronomical conditions\nsubject it, are much ameliorated; while the great proportion of land in\nthe northern hemisphere, tends to exaggerate such contrast as now\nexists in it between winter and summer: whence it results that the\nclimates of the two hemispheres are not widely unlike. But 10,000 years\nhence, the northern hemisphere will undergo annual variations of\ntemperature far more marked than now.\n\nIn the last edition of his _Outlines of Astronomy_, Sir John Herschel\nrecognizes this as an element in geological processes; regarding it as\npossibly a part-cause of those climatic changes indicated by the records\nof the Earth's past. That it has had much to do with those larger\nchanges of climate of which we have evidence, seems unlikely, since\nthere is reason to think that these have been far slower and more\nlasting; but that it must have entailed a rhythmical exaggeration and\nmitigation of the climates otherwise produced, seems beyond question.\nAnd it seems also beyond question that there must have been a consequent\nrhythmical change in the distribution of organisms--a rhythmical change\nto which we here wish to draw attention, as one cause of minor breaks in\nthe succession of fossil remains. Each species of plant and animal has\ncertain limits of heat and cold within which only it can exist; and\nthese limits in a great degree determine its geographical position. It\nwill not spread north of a certain latitude, because it cannot bear a\nmore northern winter, nor south of a certain latitude, because the\nsummer heat is too great; or else it is indirectly restrained from\nspreading further by the effect of temperature on the humidity of the\nair, or on the distribution of the organisms it lives upon. But now,\nwhat will result from a slow alteration of climate, produced as above\ndescribed? Supposing the period we set out from is that in which the\ncontrast of seasons is least marked, it is manifest that during the\nprogress towards the period of most violent contrast, each species of\nplant and animal will gradually change its limits of distribution--will\nbe driven back, here by the winter's increasing cold, and there by the\nsummer's increasing heat--will retire into those localities that are\nstill fit for it. Thus during 10,000 years, each species will ebb away\nfrom certain regions it was inhabiting; and during the succeeding 10,000\nyears will flow back into those regions. From the strata there forming,\nits remains will disappear; they will be absent from some of the\nsuperposed strata; and will be found in strata higher up. But in what\nshapes will they re-appear? Exposed during the 21,000 years of their\nslow recession and their slow return, to changing conditions of life,\nthey are likely to have undergone modifications; and will probably\nre-appear with slight differences of constitution and perhaps of\nform--will be new varieties or perhaps new sub-species.\n\nTo this cause of minor breaks in the succession of organic forms--a\ncause on which we have dwelt because it has not been taken into\naccount--we must add sundry others. Besides these periodically-recurring\nchanges of climate, there are the irregular ones produced by\nredistributions of land and sea; and these, sometimes less, sometimes\ngreater, in degree, than the rhythmical changes, must, like them, cause\nin each region emigrations and immigrations of species; and consequent\nbreaks, small or large as the case may be, in the paleontological\nseries. Other and more special geological changes must produce other and\nmore local blanks in the succession. By some inland elevation the\nnatural drainage of a continent is modified; and instead of the sediment\npreviously brought down to the sea by it, a great river brings down\nsediment unfavourable to various plants and animals living in its delta:\nwhereupon these disappear from the locality, perhaps to re-appear in a\nchanged form after a long epoch. Upheavals or subsidences of shores or\nsea-bottoms, involving deviations of marine currents, remove the\nhabitats of many species to which such currents are salutary or\ninjurious; and further, this redistribution of currents alters the\nplaces of sedimentary deposits, and thus stops the burying of organic\nremains in some localities, while commencing it in others. Had we space,\nmany more such causes of blanks in our paleontological records might be\nadded. But it is needless here to enumerate them. They are admirably\nexplained and illustrated in Sir Charles Lyell's _Principles of\nGeology_.\n\nNow, if these minor changes of the Earth's surface produce minor breaks\nin the series of fossilized remains; must not great changes produce\ngreat breaks? If a local upheaval or subsidence causes throughout its\nsmall area the absence of some links in the chain of fossil forms; does\nit not follow that an upheaval or subsidence extending over a large part\nof the Earth's surface, must cause the absence of a great number of such\nlinks throughout a very wide area?\n\nWhen during a long epoch a continent, slowly sinking, gives place to a\nfar-spreading ocean some miles in depth, at the bottom of which no\ndeposits from rivers or abraded shores can be thrown down; and when,\nafter some enormous period, this ocean-bottom is gradually elevated and\nbecomes the site for new strata; it is clear that the fossils contained\nin these new strata are likely to have but little in common with the\nfossils of the strata below them. Take, in illustration, the case of the\nNorth Atlantic. We have already named the fact that between this country\nand the United States, the ocean-bottom is being covered with a deposit\nof chalk--a deposit which has been forming, probably, ever since there\noccurred that great depression of the Earth's crust from which the\nAtlantic resulted in remote geologic times. This chalk consists of the\nminute shells of _Foraminifera_, sprinkled with remains of small\n_Entomostraca_, and probably a few Pteropod-shells; though the sounding\nlines have not yet brought up any of these last. Thus, in so far as all\nhigh forms of life are concerned, this new chalk-formation must be a\nblank. At rare intervals, perhaps, a polar bear, drifted on an iceberg,\nmay have its bones scattered over the bed; or a dead, decaying whale\nmay similarly leave traces. But such remains must be so rare, that this\nnew chalk-formation, if accessible, might be examined for a century\nbefore any of them were disclosed. If now, some millions of years hence,\nthe Atlantic-bed should be raised, and estuary deposits or shore\ndeposits laid upon it, these would contain remains of a Flora and a\nFauna so distinct from everything below them, as to appear like a new\ncreation.\n\nThus, along with continuity of life on the Earth's surface, there not\nonly _may_ be, but there _must_ be, great gaps in the series of fossils;\nand hence these gaps are no evidence against the doctrine of Evolution.\n\n       *       *       *       *       *\n\nOne other current assumption remains to be criticized; and it is the one\non which, more than on any other, depends the view taken respecting the\nquestion of development.\n\nFrom the beginning of the controversy, the arguments for and against\nhave turned upon the evidence of progression in organic forms, found in\nthe ascending series of our sedimentary formations. On the one hand,\nthose who contend that higher organisms have been evolved out of lower,\njoined with those who contend that successively higher organisms have\nbeen created at successively later periods, appeal for proof to the\nfacts of Paleontology; which, they say, countenance their views. On the\nother hand, the Uniformitarians, who not only reject the hypothesis of\ndevelopment, but deny that the modern forms of life are higher than the\nancient ones, reply that the paleontological evidence is at present very\nincomplete; that though we have not yet found remains of\nhighly-organized creatures in strata of the greatest antiquity, we must\nnot assume that no such creatures existed when those strata were\ndeposited; and that, probably, search will eventually disclose them.\n\nIt must be admitted that thus far, the evidence has gone in favour of\nthe latter party. Geological discovery has year after year shown the\nsmall value of negative facts. The conviction that there are no traces\nof higher organisms in earlier strata, has resulted not from the absence\nof such traces, but from incomplete examination. At p. 460 of his\n_Manual of Elementary Geology_, Sir Charles Lyell gives a list in\nillustration of this. It appears that in 1709, fishes were not known\nlower than the Permian system. In 1793 they were found in the subjacent\nCarboniferous system; in 1828 in the Devonian; in 1840 in the Upper\nSilurian. Of reptiles, we read that in 1710 the lowest known were in the\nPermian; in 1844 they were detected in the Carboniferous; and in 1852 in\nthe Upper Devonian. While of the Mammalia the list shows that in 1798\nnone had been discovered below the Middle Eocene: but that in 1818 they\nwere discovered in the Lower Oolite; and in 1847 in the Upper Trias.\n\nThe fact is, however, that both parties set out with an inadmissible\npostulate. Of the Uniformitarians, not only such writers as Hugh Miller,\nbut also such as Sir Charles Lyell,[27] reason as though we had found\nthe earliest, or something like the earliest, strata. Their antagonists,\nwhether defenders of the Development Hypothesis or simply\nProgressionists, almost uniformly do the like. Sir R. Murchison, who is\na Progressionist, calls the lowest fossiliferous strata, \"Protozoic.\"\nProf. Ansted uses the same term. Whether avowedly or not, all the\ndisputants stand on this assumption as their common ground.\n\nYet is this assumption indefensible, as some who make it very well know.\nFacts may be cited against it which show that it is a more than\nquestionable one--that it is a highly improbable one; while the evidence\nassigned in its favour will not bear criticism.\n\nBecause in Bohemia, Great Britain, and portions of North America, the\nlowest unmetamorphosed strata yet discovered, contain but slight traces\nof life, Sir R. Murchison conceives that they were formed while yet few,\nif any, plants or animals had been created; and, therefore, classes them\nas \"Azoic.\" His own pages, however, show the illegitimacy of the\nconclusion that there existed at that period no considerable amount of\nlife. Such traces of life as have been found in the Longmynd rocks, for\nmany years considered unfossiliferous, have been found in some of the\nlowest beds; and the twenty thousand feet of superposed beds, still\nyield no organic remains. If now these superposed strata throughout a\ndepth of four miles, are without fossils, though the strata over which\nthey lie prove that life had commenced; what becomes of Sir R.\nMurchison's inference? At page 189 of _Siluria_, a still more conclusive\nfact will be found. The \"Glengariff grits,\" and other accompanying\nstrata there described as 13,500 feet thick, contain no signs of\ncontemporaneous life. Yet Sir R. Murchison refers them to the Devonian\nperiod--a period which had a large and varied marine Fauna. How then,\nfrom the absence of fossils in the Longmynd beds and their equivalents,\ncan we conclude that the Earth was \"azoic\" when they were formed?\n\n\"But,\" it may be asked, \"if living creatures then existed, why do we not\nfind fossiliferous strata of that age, or an earlier age?\" One reply is,\nthat the non-existence of such strata is but a negative fact--we have\nnot found them. And considering how little we know even of the\ntwo-fifths of the Earth's surface now above the sea, and how absolutely\nignorant we are of the three-fifths below the sea, it is rash to say\nthat no such strata exist. But the chief reply is, that these records of\nthe Earth's earlier history have been in great part destroyed, by\nagencies which are ever tending to destroy such records.\n\nIt is an established geological doctrine, that sedimentary strata are\nliable to be changed, more or less profoundly, by igneous action. The\nrocks originally classed as \"transition,\" because they were\nintermediate in character between the igneous rocks found below them,\nand the sedimentary strata found above them, are now known to be nothing\nelse than sedimentary strata altered in texture and appearance by the\nintense heat of adjacent molten matter; and hence are renamed\n\"metamorphic rocks.\" Modern researches have shown, too, that these\nmetamorphic rocks are not, as was once supposed, all of the same age.\nBesides primary and secondary strata which have been transformed by\nigneous action, there are similarly-changed deposits of tertiary\norigin--deposits changed, even as far as a quarter of a mile from the\npoint of contact with neighbouring granite. By this process fossils are\nof course destroyed. \"In some cases,\" says Sir Charles Lyell, \"dark\nlimestones, replete with shells and corals, have been turned into white\nstatuary marble, and hard clays, containing vegetable or other remains,\ninto slates called mica-schist or hornblende-schist; every vestige of\nthe organic bodies having been obliterated.\" Again, it is fast becoming\nan acknowledged truth that igneous rock, of whatever kind, is the\nproduct of sedimentary strata which have been completely melted. Granite\nand gneiss, which are of like chemical composition, have been shown, in\nvarious cases, to pass one into the other; as at Valorsine, near Mont\nBlanc, where the two, in contact, are observed to \"both undergo a\nmodification of mineral character. The granite still remaining\nunstratified, becomes charged with green particles; and the talcose\ngneiss assumes a granitiform structure without losing its\nstratification.\" In the Aberdeen-granite, lumps of unmelted gneiss are\nabundant; and we can ourselves bear witness that the granite on the\nbanks of Loch Sunart yields proofs that, when molten, it contained\nincompletely-fused clots of sedimentary strata. Nor is this all. Fifty\nyears ago, it was thought that all granitic rocks were primitive, or\nexisted before any sedimentary strata; but it is now \"no easy task to\npoint out a single mass of granite demonstrably more ancient than all\nthe known fossiliferous deposits.\" In brief, accumulated evidence shows,\nthat by contact with, or proximity to, the molten matter of the Earth's\nnucleus, all beds of sediment are liable to be actually melted, or\npartially fused, or so heated as to agglutinate their particles; and\nthat according to the temperature they have been raised to, and the\ncircumstances under which they cool, they assume the forms of granite,\nporphyry, trap, gneiss, or rock otherwise altered. Further, it is\nmanifest that though strata of various ages have been thus changed, yet\nthe most ancient strata have been so changed to the greatest extent;\nboth because they have been nearer to the centre of igneous agency; and\nbecause they have been for longer periods liable to be affected by it.\nWhence it follows, that sedimentary strata passing a certain antiquity,\nare unlikely to be found in an unmetamorphosed state; and that strata\nmuch earlier than these are certain to have been melted up. Thus if,\nthroughout a past of indefinite duration, there had been at work those\naqueous and igneous agencies which we see still at work, the state of\nthe Earth's crust might be just what we find it. We have no evidence\nwhich puts a limit to the period throughout which this formation and\ndestruction of strata has been going on. For aught the facts prove, it\nmay have been going on for ten times the period measured by our whole\nseries of sedimentary deposits.\n\nBesides having, in the present appearances of the Earth's crust, no data\nfor fixing a commencement to these processes--besides finding that the\nevidence permits us to assume such commencement to have been\ninconceivably remote, as compared even with the vast eras of geology; we\nare not without positive grounds for inferring the inconceivable\nremoteness of such commencement. Modern geology has established truths\nwhich are irreconcilable with the belief that the formation and\ndestruction of strata began when the Cambrian rocks were formed; or at\nanything like so recent a time. One fact from _Siluria_ will suffice.\nSir R. Murchison estimates the vertical thickness of Silurian strata in\nWales, at from 26,000 to 27,000 feet, or about five miles; and if to\nthis we add the vertical depth of the Cambrian strata, on which the\nSilurians lie conformably, there results, on the lowest computation, a\ntotal depth of some seven miles. Now it is held by geologists, that this\nvast series of formations must have been deposited in an area of gradual\nsubsidence. These beds could not have been thus laid one on another in\nregular order, unless the Earth's crust had been at that place sinking,\neither continuously or by small steps. Such an immense subsidence,\nhowever, must have been impossible without a crust of great thickness.\nThe Earth's molten nucleus tends ever, with enormous force, to assume\nthe form of a regular oblate spheroid. Any depression of its crust below\nthe surface of equilibrium, and any elevation of its crust above that\nsurface, have to withstand immense resistances. It follows inevitably\nthat, with a thin crust, nothing but small elevations and subsidences\nwould have been possible; and that, conversely, a subsidence of seven\nmiles implies a crust of great strength, or, in other words, of great\nthickness. Indeed, if we compare this inferred subsidence in the\nSilurian period, with such elevations and depressions as our existing\ncontinents and oceans display, we see no evidence that the Earth's crust\nwas appreciably thinner then than now. What are the implications? If, as\ngeologists generally admit, the Earth's crust has resulted from that\nslow cooling which is even still going on--if we see no sign that at the\ntime when the earliest Cambrian strata were formed, this crust was\nappreciably thinner than now; we are forced to conclude that the era\nduring which it acquired that great thickness possessed in the Cambrian\nperiod, was enormous as compared with the interval between the Cambrian\nperiod and our own. But during the incalculable series of epochs thus\nimplied, there existed an ocean, tides, winds, waves, rain, rivers. The\nagencies by which the denudation of continents and filling up of seas\nhave all along been carried on, were as active then as now. Endless\nsuccessions of strata must have been formed. And when we ask--Where are\nthey? Nature's obvious reply is--They have been destroyed by that\nigneous action to which so great a part of our oldest-known strata owe\ntheir fusion or metamorphosis.\n\nOnly the last chapter of the Earth's history has come down to us. The\nmany previous chapters, stretching back to a time immeasurably remote,\nhave been burnt; and with them all the records of life we may presume\nthey contained. The greater part of the evidence which might have served\nto settle the Development-controversy, is for ever lost; and on neither\nside can the arguments derived from Geology be conclusive.\n\n\"But how happen there to be such evidences of progression as exist?\" it\nmay be asked. \"How happens it that, in ascending from the most ancient\nstrata to the most recent strata, we _do_ find a succession of organic\nforms, which, however irregularly, carries us from lower to higher?\"\nThis question seems difficult to answer. Nevertheless, there is reason\nfor thinking that nothing can be safely inferred from the apparent\nprogression here cited. And the illustration which shows as much, will,\nwe believe, also show how little trust is to be placed in certain\ngeological generalizations that appear to be well established. With this\nsomewhat elaborate illustration, to which we now pass, our criticisms\nmay fitly conclude.\n\n       *       *       *       *       *\n\nLet us suppose that in a region now covered by wide ocean, there begins\none of those great and gradual upheavals by which new continents are\nformed. To be precise, let us say that in the South Pacific, midway\nbetween New Zealand and Patagonia, the sea-bottom has been little by\nlittle thrust up toward the surface, and is about to emerge. What will\nbe the successive phenomena, geological and biological, which are\nlikely to occur before this emerging sea-bottom has become another\nEurope or Asia? In the first place, such portions of the incipient land\nas are raised to the level of the waves, will be rapidly denuded by\nthem: their soft substance will be torn up by the breakers, carried away\nby the local currents, and deposited in neighbouring deeper water.\nSuccessive small upheavals will bring new and larger areas within reach\nof the waves; fresh portions will each time be removed from the surfaces\npreviously denuded; and further, some of the newly-formed strata, being\nelevated nearly to the level of the water, will be washed away and\nre-deposited. In course of time the harder formations of the upraised\nsea-bottom will be uncovered. These, being less easily destroyed, will\nremain permanently above the surface; and at their margins will arise\nthe usual breaking down of rocks into beach-sand and pebbles. While in\nthe slow course of this elevation, going on at the rate of perhaps two\nor three feet in a century, most of the sedimentary deposits produced\nwill be again and again destroyed and reformed; there will, in those\nadjacent areas of subsidence which accompany areas of elevation, be more\nor less continuous successions of sedimentary deposits lying on the\npre-existing ocean bed. And now, what will be the character of these\nstrata, old and new? They will contain scarcely any traces of life. The\ndeposits that had previously been slowly formed at the bottom of this\nwide ocean, would be sprinkled with fossils of but few species. The\noceanic Fauna is not a rich one; its hydrozoa do not admit of\npreservation; and the hard parts of its few kinds of molluscs and\ncrustaceans and insects are mostly fragile. Hence, when the ocean-bed\nwas here and there raised to the surface--when its strata of sediment\nwith their contained organic fragments were torn up and long washed\nabout by the breakers before being re-deposited--when the re-deposits\nwere again and again subject to this violent abrading action by\nsubsequent small elevations, as they would mostly be; what few fragile\norganic remains they contained, would be in nearly all cases destroyed.\nThus such of the first-formed strata as survived the repeated changes of\nlevel, would be practically \"azoic;\" like the Cambrian of our\ngeologists. When by the washing away of the soft deposits, the hard\nsub-strata had been exposed in the shape of rocky islets, and a footing\nhad thus been furnished, the pioneers of a new life might be expected to\nmake their appearance. What would they be? Not any of the surrounding\noceanic species, for these are not fitted for a littoral life; but\nspecies flourishing on some of the far-distant shores of the Pacific. Of\nsuch, the first to establish themselves would be sea-weeds and\nzoophytes; because the most readily conveyed on floating wood, &c., and\nbecause when conveyed they would find fit food. It is true that\nCirrhipeds and Lamellibranchs, subsisting on the minute creatures which\neverywhere people the sea, would also find fit food. But the chances of\nearly colonization are in favour of species which, multiplying by\nagamogenesis, can people a whole shore from a single germ; and against\nspecies which, multiplying only by gamogenesis, must be introduced in\nconsiderable numbers that some may propagate. Thus we infer that the\nearliest traces of life left in the sedimentary deposits near these new\nshores, will be traces of life as humble as that indicated in the most\nancient rocks of Great Britain and Ireland. Imagine now that the\nprocesses above indicated, continue--that the emerging lands become\nwider in extent, and fringed by higher and more varied shores; and that\nthere still go on those ocean-currents which, at long intervals, convey\nfrom far distant shores immigrant forms of life. What will result? Lapse\nof time will of course favour the introduction of such new forms:\nadmitting, as it must, of those combinations of fit conditions, which\ncan occur only after long intervals. Moreover, the increasing area of\nthe islands, individually and as a group, implies increasing length of\ncoast, and therefore a longer line of contact with the streams and waves\nwhich bring drifting masses bearing germs of fresh life. And once more,\nthe comparatively-varied shores, presenting physical conditions which\nchange from mile to mile, will furnish suitable habitats for more\nnumerous species. So that as the elevation proceeds, three causes\nconspire to introduce additional marine plants and animals. To what\nclasses will the increasing Fauna be for a long period confined? Of\ncourse, to classes of which individuals, or their germs, are most liable\nto be carried far away from their native shores by floating sea-weed or\ndrift-wood; to classes which are also least likely to perish in transit,\nor from change of climate; and to those which can best subsist around\ncoasts comparatively bare of life. Evidently then, corals, annelids,\ninferior molluscs, and crustaceans of low grade, will chiefly constitute\nthe early Fauna. The large predatory members of these classes, will be\nlater in establishing themselves; both because the new shores must first\nbecome well peopled by the creatures they prey on, and because, being\nmore complex, they, or their ova, must be less likely to survive the\njourney, and the change of conditions. We may infer, then, that the\nstrata deposited next after the almost \"azoic\" strata, would contain the\nremains of invertebrata, allied to those found near the shores of\nAustralia and South America. Of such invertebrate remains, the lower\nbeds would furnish comparatively few genera, and those of relatively low\ntypes; while in the upper beds the number of genera would be greater,\nand the types higher: just as among the fossils of our Silurian system.\nAs this great geologic change slowly advanced through its long history\nof earthquakes, volcanic disturbances, minor upheavals and\nsubsidences--as the extent of the archipelago became greater and its\nsmaller islands coalesced into larger ones, while its coast-line grew\nstill longer and more varied, and the neighbouring sea more thickly\ninhabited by inferior forms of life; the lowest division of the\nvertebrata would begin to be represented. In order of time, fish would\nnaturally come later than the lower invertebrata; both as being less\nlikely to have their ova transported across the waste of waters, and as\nrequiring for their subsistence a pre-existing Fauna of some\ndevelopment. They might be expected to make their appearance along with\nthe predaceous crustaceans; as they do in the uppermost Silurian rocks.\nAnd here, too, let us remark, that as, during this long epoch we have\nbeen describing, the sea would have made great inroads on some of the\nnewly-raised lands which had remained stationary; and would probably in\nsome places have reached masses of igneous or metamorphic rocks; there\nmight, in course of time, arise by the decomposition and denudation of\nsuch rocks, local deposits coloured with oxide of iron, like our Old Red\nSandstone. And in these deposits might be buried the remains of the fish\nthen peopling the neighbouring sea.\n\nMeanwhile, how would the surfaces of the upheaved masses be occupied? At\nfirst their deserts of naked rocks would bear only the humblest forms of\nvegetal life, such as we find in grey and orange patches on our own\nrugged mountain sides; for these alone could flourish on such surfaces,\nand their spores would be the most readily transported. When, by the\ndecay of such protophytes, and that decomposition of rock effected by\nthem, there had resulted a fit habitat for mosses; these, of which the\ngerms might be conveyed in drifted trees, would begin to spread. A soil\nhaving been eventually thus produced, it would become possible for\nplants of higher organization to find roothold; and as the archipelago\nand its constituent islands grew larger, and had more multiplied\nrelations with winds and waters, such higher plants might be expected\nultimately to have their seeds transferred from the nearest lands. After\nsomething like a Flora had thus colonized the surface, it would become\npossible for insects to exist; and of air-breathing creatures, insects\nwould manifestly be among the first to find their way from elsewhere.\nAs, however, terrestrial organisms, both vegetal and animal, are less\nlikely than marine organisms to survive the accidents of transport from\ndistant shores; it is inferable that long after the sea surrounding\nthese new lands had acquired a varied Flora and Fauna, the lands\nthemselves would still be comparatively bare; and thus that the early\nstrata, like our Silurians, would afford no traces of terrestrial life.\nBy the time that large areas had been raised above the ocean, we may\nfairly suppose a luxuriant vegetation to have been acquired. Under what\ncircumstances are we likely to find this vegetation fossilized? Large\nsurfaces of land imply large rivers with their accompanying deltas; and\nare liable to have lakes and swamps. These, as we know from extant\ncases, are favourable to rank vegetation; and afford the conditions\nneedful for preserving it in coal-beds. Observe, then, that while in the\nearly history of such a continent a carboniferous period could not\noccur, the occurrence of a carboniferous period would become probable\nafter long-continued upheavals had uncovered large areas. As in our own\nsedimentary series, coal-beds would make their appearance only after\nthere had been enormous accumulations of earlier strata charged with\nmarine fossils.\n\nLet us ask next, in what order the higher forms of animal life would\nmake their appearance. We have seen how, in the succession of marine\nforms, there would be something like a progress from the lower to the\nhigher: bringing us in the end to predaceous molluscs, crustaceans, and\nfish. What are likely to succeed fish? After marine creatures, those\nwhich would have the greatest chance of surviving the voyage would be\namphibious reptiles; both because they are more tenacious of life than\nhigher animals, and because they would be less completely out of their\nelement. Such reptiles as can live in both fresh and salt water, like\nalligators; and such as are drifted out of the mouths of great rivers on\nfloating trees, as Humboldt says the Orinoco alligators are; might be\nearly colonists. It is manifest, too, that reptiles of other kinds would\nbe among the first vertebrata to people the new continent. If we\nconsider what will occur on one of those natural rafts of trees, soil,\nand matted vegetable matter, sometimes swept out to sea by such currents\nas the Mississippi, with a miscellaneous living cargo; we shall see that\nwhile the active, hot-blooded, highly-organized creatures will soon die\nof starvation and exposure, the inert, cold-blooded ones, which can go\nlong without food, will live perhaps for weeks; and so, out of the\nchances from time to time occurring during long periods, reptiles will\nbe the first to get safely landed on foreign shores: as indeed they are\neven now known sometimes to be. The transport of mammalia being\ncomparatively precarious, must, in the order of probability, be longer\npostponed; and would, indeed, be unlikely to occur until by the\nenlargement of the new continent, the distances of its shores from\nadjacent lands had been greatly diminished, or the formation of\nintervening islands had increased the chances of survival. Assuming,\nhowever, that the facilities for immigration had become adequate; which\nwould be the first mammals to arrive and live? Not large herbivores; for\nthey would be soon drowned if by any accident carried out to sea. Not\nthe carnivora; for these would lack appropriate food, even if they\noutlived the voyage. Small quadrupeds frequenting trees, and feeding on\ninsects, would be those most likely both to be drifted away from their\nnative lands and to find fit food in a new one. Insectivorous mammals,\nlike in size to those found in the Trias and the Stonesfield slate,\nmight naturally be looked for as the pioneers of the higher vertebrata.\nAnd if we suppose the facilities of communication to be again increased,\neither by a further shallowing of the intervening sea and a consequent\nmultiplication of islands, or by an actual junction of the new continent\nwith an old one, through continued upheavals; we should finally have an\ninflux of the larger and more perfect mammals.\n\nNow rude as is this sketch of a process that would be extremely\nelaborate and involved, and open as some of its propositions are to\ncriticisms which there is no space here to meet; no one will deny that\nit represents something like the biologic history of the supposed new\ncontinent. Details apart, it is manifest that simple organisms, able to\nflourish under simple conditions of life, would be the first successful\nimmigrants; and that more complex organisms, needing for their existence\nthe fulfilment of more complex conditions, would afterwards establish\nthemselves in something like an ascending succession. At the one extreme\nwe see every facility. The new individuals can be conveyed in the shape\nof minute germs; immense numbers of these are perpetually being carried\nin all directions to great distances by ocean-currents--either detached\nor attached to floating bodies; they can find nutriment wherever they\narrive; and the resulting organisms can multiply asexually with great\nrapidity. At the other extreme, we see every difficulty. The new\nindividuals must be conveyed in their adult forms; their numbers are, in\ncomparison, utterly insignificant; they live on land, and are very\nunlikely to be carried out to sea; when so carried, the chances are\nimmense against their escape from drowning, starvation, or death by\ncold; if they survive the transit, they must have a pre-existing Flora\nor Fauna to supply their special food; they require, also, the\nfulfilment of various other physical conditions; and unless at least two\nindividuals of different sexes are safely landed, the race cannot be\nestablished. Manifestly, then, the immigration of each successively\nhigher order of organisms, having, from one or other additional\ncondition to be fulfilled, an enormously-increased probability against\nit, would naturally be separated from the immigration of a lower order\nby some period like a geologic epoch. And thus the successive\nsedimentary deposits formed while this new continent was undergoing\ngradual elevation, would seem to furnish clear evidence of a general\nprogress in the forms of life. That lands thus raised up in the midst of\na wide ocean, would first give origin to unfossiliferous strata; next,\nto strata containing only the lowest marine forms; next to strata\ncontaining only the higher marine forms, ascending finally to fish; and\nthat the strata above these would contain reptiles, then small mammals,\nthen great mammals; seems to us demonstrable. And if the succession of\nfossils presented by the strata of this supposed new continent, would\nthus simulate the succession presented by our own sedimentary series;\nmust we not conclude that our own sedimentary series very possibly\nrecords nothing more than the phenomena accompanying one of these great\nupheavals? The probability of this conclusion being admitted, it must be\nadmitted that the facts of Paleontology can never suffice either to\nprove or disprove the Development Hypothesis; but that the most they can\ndo is to show whether the last few pages of the Earth's biologic\nhistory, are or are not in harmony with this hypothesis--whether the\nexisting Flora and Fauna can or can not be affiliated upon the Flora and\nFauna of the most recent geologic times.\n\nFOOTNOTE:\n\n[Footnote 27: Sir Charles Lyell is no longer to be classed among\nUniformitarians. With rare and admirable candour he has, since this was\nwritten, yielded to the arguments of Mr. Darwin.]\n\n\n\n\nBAIN ON THE EMOTIONS AND THE WILL.\n\n    [_First published in_ The Medico-Chirurgical Review _for January,_\n    1860.]\n\n\nAfter the controversy between the Neptunists and the Vulcanists had been\nlong carried on without definite results, there came a reaction against\nall speculative geology. Reasoning without adequate data having led to\nnothing, inquirers went into the opposite extreme, and confining\nthemselves wholly to collecting data, relinquished reasoning. The\nGeological Society of London was formed with the express object of\naccumulating evidence; for many years hypotheses were forbidden at its\nmeetings: and only of late have attempts to organize the mass of\nobservations into consistent theory been tolerated.\n\nThis reaction and subsequent re-reaction, well illustrate the recent\nhistory of English thought in general. The time was when our countrymen\nspeculated, certainly to as great an extent as any other people, on all\nthose high questions which present themselves to the human intellect;\nand, indeed, a glance at the systems of philosophy that are or have been\ncurrent on the Continent, suffices to show how much other nations owe to\nthe discoveries of our ancestors. For a generation or two, however,\nthese more abstract subjects have fallen into neglect; and, among those\nwho plume themselves on being \"practical,\" even into contempt. Partly,\nperhaps, a natural accompaniment of our rapid material growth, this\nintellectual phase has been in great measure due to the exhaustion of\nargument, and the necessity for better data. Not so much with a\nconscious recognition of the end to be subserved, as from an unconscious\nsubordination to that rhythm traceable in social changes as in other\nthings, an era of theorizing without observing, has been followed by an\nera of observing without theorizing. During this long-continued devotion\nto concrete science, an immense quantity of raw material for abstract\nscience has been accumulated; and now there is obviously commencing a\nperiod in which this accumulated raw material will be organized into\nconsistent theory. On all sides--equally in the inorganic sciences, in\nthe science of life, and in the science of society--we may note the\ntendency to pass from the superficial and empirical to the more profound\nand rational.\n\nIn Psychology this change is conspicuous. The facts brought to light by\nanatomists and physiologists during the last fifty years, are at length\nbeing used towards the interpretation of this highest class of\nbiological phenomena; and already there is promise of a great advance.\nThe work of Mr. Alexander Bain, of which the second volume has been\nrecently issued, may be regarded as especially characteristic of the\ntransition. It gives us, in orderly arrangement, the great mass of\nevidence supplied by modern science towards the building-up of a\ncoherent system of mental philosophy. It is not in itself a system of\nmental philosophy, properly so called; but a classified collection of\nmaterials for such a system, presented with that method and insight\nwhich scientific discipline generates, and accompanied with occasional\npassages of an analytical character. It is indeed that which it in the\nmain professes to be--a natural history of the mind. Were we to say that\nthe researches of the naturalist who collects and dissects and describes\nspecies, bear the same relation to the researches of the comparative\nanatomist tracing out the laws of organization, which Mr. Bain's\nlabours bear to the labours of the abstract psychologist, we should be\ngoing somewhat too far; for Mr. Bain's work is not wholly descriptive.\nStill, however, such an analogy conveys the best general conception of\nwhat he has done; and serves most clearly to indicate its needfulness.\nFor as, before there can be made anything like true generalizations\nrespecting the classification of organisms and the laws of organization,\nthere must be an extensive accumulation of the facts presented in\nnumerous organic bodies; so, without a tolerably-complete delineation of\nmental phenomena of all orders, there can scarcely arise any adequate\ntheory of mind. Until recently, mental science has been pursued much as\nphysical science was pursued by the ancients; not by drawing conclusions\nfrom observations and experiments, but by drawing them from arbitrary _a\npriori_ assumptions. This course, long since abandoned in the one case\nwith immense advantage, is gradually being abandoned in the other; and\nthe treatment of Psychology as a division of natural history, shows that\nthe abandonment will soon be complete.\n\nEstimated as a means to higher results, Mr. Bain's work is of great\nvalue. Of its kind it is the most scientific in conception, the most\ncatholic in spirit, and the most complete in execution. Besides\ndelineating the various classes of mental phenomena as seen under that\nstronger light thrown on them by modern science, it includes in the\npicture much which previous writers had omitted--partly from prejudice,\npartly from ignorance. We refer more especially to the participation of\nbodily organs in mental changes; and the addition to the primary mental\nchanges, of those many secondary ones which the actions of the bodily\norgans generate. Mr. Bain has, we believe, been the first to appreciate\nthe importance of this element in our states of consciousness; and it is\none of his merits that he shows how constant and large an element it is.\nFurther, the relations of voluntary and involuntary movements are\nelucidated in a way that was not possible to writers unacquainted with\nthe modern doctrine of reflex action. And beyond this, some of the\nanalytical passages that here and there occur, contain important ideas.\n\nValuable, however, as is Mr. Bain's work, we regard it as essentially\ntransitional. It presents in a digested form the results of a period of\nobservation; adds to these results many well-delineated facts collected\nby himself; arranges new and old materials with that more scientific\nmethod which the discipline of our times has fostered; and so prepares\nthe way for better generalizations. But almost of necessity its\nclassifications and conclusions are provisional. In the growth of each\nscience, not only is correct observation needful for the formation of\ntrue theory; but true theory is needful as a preliminary to correct\nobservation. Of course we do not intend this assertion to be taken\nliterally; but as a strong expression of the fact that the two must\nadvance hand in hand. The first crude theory or rough classification,\nbased on very slight knowledge of the phenomena, is requisite as a means\nof reducing the phenomena to some kind of order; and as supplying a\nconception with which fresh phenomena may be compared, and their\nagreement or disagreement noted. Incongruities being by and by made\nmanifest by wider examination of cases, there comes such modification of\nthe theory as brings it into a nearer correspondence with the evidence.\nThis reacts to the further advance of observation. More extensive and\ncomplete observation brings additional corrections of theory; and so on\ntill the truth is reached. In mental science, the systematic collection\nof facts having but recently commenced, it is not to be expected that\nthe results can be at once rightly formulated. All that may be looked\nfor are approximate generalizations which will presently serve for the\nbetter directing of inquiry. Hence, even were it not now possible to say\nin what way it does so, we might be tolerably certain that Mr. Bain's\nwork bears the stamp of the inchoate state of Psychology.\n\nWe think, however, that it will not be difficult to find in what\nrespects its organization is provisional; and at the same time to show\nwhat must be the nature of a more complete organization. We propose here\nto attempt this: illustrating our positions from his recently-issued\nsecond volume.\n\n       *       *       *       *       *\n\nIs it possible to make a true classification without the aid of\nanalysis? or must there not be an analytical basis to every true\nclassification? Can the real relations of things be determined by the\nobvious characteristics of the things? or does it not commonly happen\nthat certain hidden characteristics, on which the obvious ones depend,\nare the truly significant ones? This is the preliminary question which a\nglance at Mr. Bain's scheme of the emotions suggests.\n\nThough not avowedly, yet by implication, Mr. Bain assumes that a right\nconception of the nature, the order, and the relations of the emotions,\nmay be arrived at by contemplating their conspicuous objective and\nsubjective characters, as displayed in the adult. After pointing out\nthat we lack those means of classification which serve in the case of\nthe sensations, he says--\n\n     \"In these circumstances we must turn our attention to _the manner\n     of diffusion_ of the different passions and emotions, in order to\n     obtain a basis of classification analogous to the arrangement of\n     the sensations. If what we have already advanced on that subject be\n     at all well founded, this is the genuine turning point of the\n     method to be chosen, for the same mode of diffusion will always be\n     accompanied by the same mental experience, and each of the two\n     aspects would identify, and would be evidence of, the other. There\n     is, therefore, nothing so thoroughly characteristic of any state of\n     feeling as the nature of the diffusive wave that embodies it, or\n     the various organs specially roused into action by it, together\n     with the manner of the action. The only drawback is our comparative\n     ignorance, and our inability to discern the precise character of\n     the diffusive currents in every case; a radical imperfection in the\n     science of mind as constituted at present.\n\n     \"Our own consciousness, formerly reckoned the only medium of\n     knowledge to the mental philosopher, must therefore be still\n     referred to as a principal means of discriminating the varieties of\n     human feeling. We have the power of noting agreement and difference\n     among our conscious states, and on this we can raise a structure of\n     classification. We recognise such generalities as pleasure, pain,\n     love, anger, through the property of mental or intellectual\n     discrimination that accompanies in our mind the fact of emotion. A\n     certain degree of precision is attainable by this mode of mental\n     comparison and analysis; the farther we can carry such precision\n     the better; but that is no reason why it should stand alone to the\n     neglect of the corporeal embodiments through which one mind reveals\n     itself to others. The companionship of inward feeling with bodily\n     manifestation is a fact of the human constitution, and deserves to\n     be studied as such; and it would be difficult to find a place more\n     appropriate than a treatise on the mind for setting forth the\n     conjunctions and sequences traceable in this department of nature.\n     I shall make no scruple in conjoining with the description of the\n     mental phenomena the physical appearances, in so far as I am able\n     to ascertain them.\n\n     \"There is still one other quarter to be referred to in settling a\n     complete arrangement of the emotions, namely, the varieties of\n     human conduct, and the machinery created in subservience to our\n     common susceptibilities. For example, the vast superstructure of\n     fine art has its foundations in human feeling, and in rendering an\n     account of this we are led to recognise the interesting group of\n     artistic or aesthetic emotions. The same outward reference to\n     conduct and creations brings to light the so-called moral sense in\n     man, whose foundations in the mental system have accordingly to be\n     examined.\n\n     \"Combining together these various indications, or sources of\n     discrimination,--outward objects, diffusive mode or expression,\n     inward consciousness, resulting conduct and institutions,--I adopt\n     the following arrangement of the families or natural orders of\n     emotion.\"\n\nHere, then, are confessedly adopted, as bases of classification, the\nmost manifest characters of the emotions; as discerned subjectively, and\nobjectively. The mode of diffusion of an emotion is one of its outside\naspects; the institutions it generates form another of its outside\naspects; and though the peculiarities of the emotion as a state of\nconsciousness, seem to express its intrinsic and ultimate nature, yet\nsuch peculiarities as are perceptible by simple introspection, must also\nbe classed as superficial peculiarities. It is a familiar fact that\nvarious intellectual states of consciousness turn out, when analyzed, to\nhave natures widely unlike those which at first appear; and we believe\nthe like will prove true of emotional states of consciousness. Just as\nour concept of space, which is apt to be thought a simple,\nundecomposable concept, is yet resolvable into experiences quite\ndifferent from that state of consciousness which we call space; so,\nprobably, the sentiment of affection or reverence is compounded of\nelements that are severally distinct from the whole which they make up.\nAnd much as a classification of our ideas which dealt with the idea of\nspace as though it were ultimate, would be a classification of ideas by\ntheir externals; so, a classification of our emotions, which, regarding\nthem as simple, describes their aspects in ordinary consciousness, is a\nclassification of emotions by their externals.\n\nThus, then, Mr. Bain's grouping is throughout determined by the most\nmanifest attributes--those objectively displayed in the natural language\nof the emotions, and in the social phenomena that result from them, and\nthose subjectively displayed in the aspects the emotions assume in an\nanalytical consciousness. And the question is--Can they be correctly\ngrouped after this method?\n\nWe think not; and had Mr. Bain carried farther an idea with which he has\nset out, he would probably have seen that they cannot. As already said,\nhe avowedly adopts \"the natural-history-method:\" not only referring to\nit in his preface, but in his first chapter giving examples of botanical\nand zoological classifications, as illustrating the mode in which he\nproposes to deal with the emotions. This we conceive to be a\nphilosophical conception; and we have only to regret that Mr. Bain has\noverlooked some of its most important implications. For in what has\nessentially consisted the progress of natural-history-classification? In\nthe abandonment of grouping by external, conspicuous characters; and in\nthe making of certain internal, but all-essential characters, the bases\nof groups. Whales are not now ranged along with fish, because in their\ngeneral forms and habits of life they resemble fish; but they are\nranged with mammals, because the type of their organization, as\nascertained by dissection, corresponds with that of mammals. No longer\nconsidered as sea-weeds in virtue of their forms and modes of growth,\n_Polyzoa_ are now shown, by examination of their economy, to belong to\nthe animal kingdom. It is found, then, that the discovery of real\nrelationships involves analysis. It has turned out that the earlier\nclassifications, guided by general resemblances, though containing much\ntruth, and though very useful provisionally, were yet in many cases\nradically wrong; and that the true affinities of organisms, and the true\nhomologies of their parts, are to be made out only by examining their\nhidden structures. Another fact of great significance in the history of\nclassification is also to be noted. Very frequently the kinship of an\norganism cannot be made out even by exhaustive analysis, if that\nanalysis is confined to the adult structure. In many cases it is needful\nto examine the structure in its earlier stages; and even in its\nembryonic stage. So difficult was it, for instance, to determine the\ntrue position of the _Cirrhipedia_ among animals, by examining mature\nindividuals only, that Cuvier erroneously classed them with _Mollusca_,\neven after dissecting them; and not until their early forms were\ndiscovered, were they clearly proved to belong to the _Crustacea_. So\nimportant, indeed, is the study of development as a means to\nclassification, that the first zoologists now hold it to be the only\nabsolute criterion.\n\nHere, then, in the advance of natural-history-classification, are two\nfundamental facts, which should be borne in mind when classifying the\nemotions. If, as Mr. Bain rightly assumes, the emotions are to be\ngrouped after the natural-history-method; then it should be the\nnatural-history-method in its complete form, and not in its rude form.\nMr. Bain will doubtless agree in the belief, that a correct account of\nthe emotions in their natures and relations, must correspond with a\ncorrect account of the nervous system--must form another side of the\nsame ultimate facts. Structure and function must necessarily harmonize.\nStructures which have with each other certain ultimate connexions, must\nhave functions which have answering connexions. Structures which have\narisen in certain ways, must have functions which have arisen in\nparallel ways. And hence if analysis and development are needful for the\nright interpretation of structures, they must be needful for the right\ninterpretation of functions. Just as a scientific description of the\ndigestive organs must include not only their obvious forms and\nconnexions, but their microscopic characters, and also the ways in which\nthey severally result by differentiation from the primitive mucous\nmembrane; so must a scientific account of the nervous system include its\ngeneral arrangements, its minute structure, and its mode of evolution;\nand so must a scientific account of nervous actions include the\nanswering three elements. Alike in classing separate organisms, and\nin classing the parts of the same organism, the complete\nnatural-history-method involves ultimate analysis, aided by development;\nand Mr. Bain, in not basing his classification of the emotions on\ncharacters reached through these aids, has fallen short of the\nconception with which he set out.\n\n\"But,\" it will perhaps be asked, \"how are the emotions to be analyzed,\nand their modes of evolution to be ascertained? Different animals, and\ndifferent organs of the same animal, may readily be compared in their\ninternal structures and microscopic structures, as also in their\ndevelopments; but functions, and especially such functions as the\nemotions, do not admit of like comparisons.\"\n\nIt must be admitted that the application of these methods is here by no\nmeans so easy. Though we can note differences and similarities between\nthe internal formations of two animals; it is difficult to contrast the\nmental states of two animals. Though the true morphological relations of\norgans may be made out by observation of embryos; yet, where such organs\nare inactive before birth, we cannot completely trace the history of\ntheir actions. Obviously, too, pursuance of inquiries of the kind\nindicated, raises questions which science is not yet prepared to answer;\nas, for instance--Whether all nervous functions, in common with all\nother functions, arise by gradual differentiations, as their organs do?\nWhether the emotions are, therefore, to be regarded as divergent modes\nof action that have become unlike by successive modifications? Whether,\nas two organs which originally budded out of the same membrane have not\nonly become different as they developed, but have also severally become\ncompound internally, though externally simple; so two emotions, simple\nand near akin in their roots, may not only have grown unlike, but may\nalso have grown involved in their natures, though seeming homogeneous to\nconsciousness? And here, indeed, in the inability of existing science to\nanswer these questions which underlie a true psychological\nclassification, we see how purely provisional any present classification\nis likely to be.\n\nNevertheless, even now, classification may be aided by development and\nultimate analysis to a considerable extent; and the defect in Mr. Bain's\nwork is, that he has not systematically availed himself of them as far\nas possible. Thus we may, in the first place, study the evolution of the\nemotions up through the various grades of the animal kingdom: observing\nwhich of them are earliest and exist with the lowest organization and\nintelligence; in what order the others accompany higher endowments; and\nhow they are severally related to the conditions of life. In the second\nplace, we may note the emotional differences between the lower and the\nhigher human races--may regard as earlier and simpler those feelings\nwhich are common to both, and as later and more compound those which are\ncharacteristic of the most civilized. In the third place, we may observe\nthe order in which the emotions unfold during the progress from infancy\nto maturity. And lastly, comparing these three kinds of emotional\ndevelopment, displayed in the ascending grades of the animal kingdom,\nin the advance of the civilized races, and in individual history, we may\nsee in what respects they harmonize, and what are the implied general\ntruths.\n\nHaving gathered together and generalized these several classes of facts,\nanalysis of the emotions would be made easier. Setting out with the\nassumption that every new form of emotion making its appearance in the\nindividual or the race, is a modification of some pre-existing emotion,\nor a compound of several pre-existing emotions, we should be greatly\naided by knowing what always are the pre-existing emotions. When, for\nexample, we find that very few of the lower animals show any love of\naccumulation, and that this feeling is absent in infancy--when we see\nthat an infant in arms exhibits anger, fear, wonder, while yet it\nmanifests no desire of permanent possession, and that a brute which has\nno acquisitiveness can nevertheless feel attachment, jealousy, love of\napprobation; we may suspect that the feeling which property satisfies is\ncompounded out of simpler and deeper feelings. We may conclude that as,\nwhen a dog hides a bone, there must exist in him a prospective\ngratification of hunger; so there must similarly at first, in all cases\nwhere anything is secured or taken possession of, exist an ideal\nexcitement of the feeling which that thing will gratify. We may further\nconclude that when the intelligence is such that a variety of objects\ncome to be utilized for different purposes--when, as among savages,\ndivers wants are satisfied through the articles appropriated for\nweapons, shelter, clothing, ornament; the act of appropriating comes to\nbe one constantly involving agreeable associations, and one which is\ntherefore pleasurable, irrespective of the end subserved. And when, as\nin civilized life, the property acquired is of a kind not conducing to\none order of gratification in particular, but is capable of\nadministering to all gratifications, the pleasure of acquiring property\ngrows more distinct from each of the various pleasures subserved--is\nmore completely differentiated into a separate emotion.\n\nThis illustration, roughly as it is sketched, will show what we mean by\nthe use of comparative psychology in aid of classification. Ascertaining\nby induction the actual order of evolution of the emotions, we are led\nto suspect this to be their order of successive dependence; and are so\nled to recognize their order of ascending complexity; and by consequence\ntheir true groupings.\n\nThus, in the very process of arranging the emotions into grades,\nbeginning with those involved in the lowest forms of conscious activity\nand ending with those peculiar to the adult civilized man, the way is\nopened for that ultimate analysis which alone can lead us to the true\nscience of the matter. For when we find both that there exist in a man\nfeelings which do not exist in a child, and that the European is\ncharacterized by some sentiments which are wholly or in great part\nabsent from the savage--when we see that, besides the new emotions which\narise spontaneously as the individual becomes completely organized,\nthere are new emotions making their appearance in the more advanced\ndivisions of our race; we are led to ask--How are new emotions\ngenerated? The lowest savages have not even the ideas of justice or\nmercy: they have neither words for them nor can they be made to conceive\nthem; and the manifestation of them by Europeans they ascribe to fear or\ncunning. There are aesthetic emotions common among ourselves, which are\nscarcely in any degree experienced by some inferior races; as, for\ninstance, those produced by music. To which instances may be added the\nless marked but more numerous contrasts that exist between civilized\nraces in the degrees of their several emotions. And if it is manifest,\nboth that all the emotions are capable of being permanently modified in\nthe course of successive generations, and that what must be classed as\nnew emotions may be brought into existence; then it follows that nothing\nlike a true conception of the emotions is to be obtained, until we\nunderstand how they are evolved.\n\nComparative Psychology, while it raises this inquiry, prepares the way\nfor answering it. When observing the differences between races, we can\nscarcely fail to observe also how these differences correspond with\ndifferences between their conditions of existence, and consequent\nactivities. Among the lowest races of men, love of property stimulates\nto the obtainment only of such things as satisfy immediate desires, or\ndesires of the immediate future. Improvidence is the rule: there is\nlittle effort to meet remote contingencies. But the growth of\nestablished societies having gradually given security of possession,\nthere has been an increasing tendency to provide for coming years: there\nhas been a constant exercise of the feeling which is satisfied by a\nprovision for the future; and there has been a growth of this feeling so\ngreat that it now prompts accumulation to an extent beyond what is\nneedful. Note, again, that under the discipline of social life--under a\ncomparative abstinence from aggressive actions, and a performance of\nthose naturally-serviceable actions implied by the division of\nlabour--there has been a development of those gentle emotions of which\ninferior races exhibit but the rudiments. Savages delight in giving pain\nrather than pleasure--are almost devoid of sympathy; while among\nourselves, philanthropy organizes itself in laws, establishes numerous\ninstitutions, and dictates countless private benefactions.\n\nFrom which and other like facts, does it not seem an unavoidable\ninference, that new emotions are developed by new experiences--new\nhabits of life? All are familiar with the truth that, in the individual,\neach feeling may be strengthened by performing those actions which it\nprompts; and to say that the feeling is _strengthened_, is to say that\nit is in part _made_ by these actions. We know, further, that not\nunfrequently, individuals, by persistence in special courses of conduct,\nacquire special likings for such courses, disagreeable as these may be\nto others; and these whims, or morbid tastes, imply incipient emotions\ncorresponding to these special activities. We know that emotional\ncharacteristics, in common with all others, are hereditary; and the\ndifferences between civilized nations descended from the same stock,\nshow us the cumulative results of small modifications hereditarily\ntransmitted. And when we see that between savage and civilized races\nwhich diverged from one another in the remote past, and have for a\nhundred generations followed modes of life becoming ever more unlike,\nthere exist still greater emotional contrasts; may we not infer that the\nmore or less distinct emotions which characterize civilized races, are\nthe organized results of certain daily-repeated combinations of mental\nstates which social life involves? Must we not say that habits not only\nmodify emotions in the individual, and not only beget tendencies to like\nhabits and accompanying emotions in descendants, but that when the\nconditions of the race make the habits persistent, this progressive\nmodification may go on to the extent of producing emotions so far\ndistinct as to seem new? And if so, we may suspect that such new\nemotions, and by implication all emotions analytically considered,\nconsist of aggregated and consolidated groups of those simpler feelings\nwhich habitually occur together in experience. When, in the\ncircumstances of any race, some one kind of action or set of actions,\nsensation or set of sensations, is usually followed, or accompanied, by\nvarious other sets of actions or sensations, and so entails a large mass\nof pleasurable or painful states of consciousness; these, by frequent\nrepetition, become so connected together that the initial action or\nsensation brings the ideas of all the rest crowding into consciousness:\nproducing, in some degree, the pleasures or pains that have before been\nfelt in reality. And when this relation, besides being frequently\nrepeated in the individual, occurs in successive generations, all the\nmany nervous actions involved tend to grow organically connected. They\nbecome incipiently reflex; and, on the occurrence of the appropriate\nstimulus, the whole nervous apparatus which in past generations was\nbrought into activity by this stimulus, becomes nascently excited. Even\nwhile yet there have been no individual experiences, a vague feeling of\npleasure or pain is produced; constituting what we may call the body of\nthe emotion. And when the experiences of past generations come to be\nrepeated in the individual, the emotion gains both strength and\ndefiniteness; and is accompanied by the appropriate specific ideas.\n\nThis view of the matter, which we believe the established truths of\nPhysiology and Psychology unite in indicating, and which is the view\nthat generalizes the phenomena of habit, of national characteristics, of\ncivilization in its moral aspects, at the same time that it gives us a\nconception of emotion in its origin and ultimate nature, may be\nillustrated from the mental modifications undergone by animals. On\nnewly-discovered lands not inhabited by man, birds are so devoid of fear\nas to allow themselves to be knocked over with sticks; but in the course\nof generations, they acquire such a dread of man as to fly on his\napproach; and this dread is manifested by young as well as by old. Now\nunless this change be ascribed to the killing-off of the less fearful,\nand the preservation and multiplication of the more fearful, which,\nconsidering the comparatively small number killed by man, is an\ninadequate cause; it must be ascribed to accumulated experiences; and\neach experience must be held to have a share in producing it. We must\nconclude that in each bird which escapes with injuries inflicted by man,\nor is alarmed by the outcries of other members of the flock (gregarious\ncreatures of any intelligence being necessarily more or less\nsympathetic), there is established an association of ideas between the\nhuman aspect and the pains, direct and indirect, suffered from human\nagency. And we must further conclude that the state of consciousness\nwhich impels the bird to take flight, is at first nothing more than an\nideal reproduction of those painful impressions which before followed\nman's approach; that such ideal reproduction becomes more vivid and more\nmassive as the painful experiences, direct or sympathetic, increase; and\nthat thus the emotion in its incipient state, is nothing else than an\naggregation of the revived pains before experienced. As, in the course\nof generations, the young birds of this race begin to display a fear of\nman before yet they have been injured by him, it is an unavoidable\ninference that the nervous system of the race has been organically\nmodified by these experiences: we have no choice but to conclude that\nwhen a young bird is thus led to fly, it is because the impression\nproduced on its senses by the approaching man, entails, through an\nincipiently-reflex action, a partial excitement of all those nerves\nwhich in its ancestors had been excited under the like conditions; that\nthis partial excitement has its accompanying painful consciousness; and\nthat the vague painful consciousness thus arising, constitutes emotion\nproper--_emotion undecomposable into specific experiences, and therefore\nseemingly homogeneous_.\n\nIf such be the explanation of the fact in this case, then it is in all\ncases. If emotion is so generated here, then it is so generated\nthroughout. We must perforce conclude that the emotional modifications\ndisplayed by different nations, and those higher emotions by which\ncivilized are distinguished from savage, are to be accounted for on the\nsame principle. And concluding this, we are led strongly to suspect that\nthe emotions in general have severally thus originated.\n\nPerhaps we have now made sufficiently clear what we mean by the study of\nthe emotions through analysis and development. We have aimed to justify\nthe positions that, without analysis aided by development, there cannot\nbe a true natural history of the emotions; and that a natural history of\nthe emotions based on external characters can be but provisional. We\nthink that Mr. Bain, in confining himself to an account of the emotions\nas they exist in the adult civilized man, has neglected those classes of\nfacts out of which the science of the matter must chiefly be built. It\nis true that he has treated of habits as modifying emotions in the\nindividual; but he has not recognized the fact that where conditions\nrender habits persistent in successive generations, such modifications\nare cumulative: he has not hinted that the modifications produced by\nhabit are emotions in the making. It is true, also, that he occasionally\nrefers to the characteristics of children; but he does not\nsystematically trace the changes through which childhood passes into\nmanhood, as throwing light on the order and genesis of the emotions. It\nis further true that he here and there refers to national traits in\nillustration of his subject; but these stand as isolated facts, having\nno general significance: there is no hint of any relation between them\nand the national circumstances; while all those many moral contrasts\nbetween lower and higher races which throw great light on\nclassification, are passed over. And once more, it is true that many\npassages of his work, and sometimes, indeed, whole sections of it, are\nanalytical; but his analyses are incidental--they do not underlie his\nentire scheme, but are here and there added to it. In brief, he has\nwritten a Descriptive Psychology, which does not appeal to Comparative\nPsychology and Analytical Psychology for its leading ideas. And in doing\nthis, he has omitted much that should be included in a natural history\nof the mind; while to that part of the subject with which he has dealt,\nhe has given a necessarily-imperfect organization.\n\n       *       *       *       *       *\n\nEven leaving out of view the absence of those methods and criteria on\nwhich we have been insisting, it appears to us that meritorious as is\nMr. Bain's book in its details, it is defective in some of its leading\nideas. The first paragraphs of his first chapter, quite startled us by\nthe strangeness of their definitions--a strangeness which can scarcely\nbe ascribed to laxity of expression. The paragraphs run thus:--\n\n     \"Mind is comprised under three heads,--Emotion, Volition, and\n     Intellect.\n\n     \"EMOTION is the name here used to comprehend all that is understood\n     by feelings, states of feeling, pleasures, pains, passions,\n     sentiments, affections. Consciousness, and conscious states also\n     for the most part denote modes of emotion, although there is such a\n     thing as the Intellectual consciousness.\n\n     \"VOLITION, on the other hand, indicates the great fact that our\n     Pleasures and Pains, which are not the whole of our emotions,\n     prompt to action, or stimulate the active machinery of the living\n     framework to perform such operations as procure the first and abate\n     the last. To withdraw from a scalding heat, and cling to a gentle\n     warmth, are exercises of volition.\"\n\nThe last of these definitions, which we may most conveniently take\nfirst, seems to us very faulty. We cannot but feel astonished that Mr.\nBain, familiar as he is with the phenomena of reflex action, should have\nso expressed himself as to include a great part of them along with the\nphenomena of volition. He seems to be ignoring the discriminations of\nmodern science, and returning to the vague conceptions of the past--nay\nmore, he is comprehending under volition what even the popular speech\nwould hardly bring under it. If you were to blame any one for snatching\nhis foot from the scalding water into which he had inadvertently put it,\nhe would tell you that he could not help it; and his reply would be\nindorsed by the general experience, that the withdrawal of a limb from\ncontact with something extremely hot, is quite involuntary--that it\ntakes place not only without volition, but in defiance of an effort of\nwill to maintain the contact. How, then, can that be instanced as an\nexample of volition, which occurs even when volition is antagonistic? We\nare quite aware that it is impossible to draw any absolute line of\ndemarcation between automatic actions and actions which are not\nautomatic. Doubtless we may pass gradually from the purely reflex,\nthrough the consensual, to the voluntary. Taking the case Mr. Bain\ncites, it is manifest that from a heat of such moderate degree that the\nwithdrawal from it is wholly voluntary, we may advance by infinitesimal\nsteps to a heat which compels involuntary withdrawal; and that there is\na stage at which the voluntary and involuntary actions are mixed. But\nthe difficulty of absolute discrimination is no reason for neglecting\nthe broad general contrast; any more than it is for confounding light\nwith darkness. If we are to include as examples of volition, all cases\nin which pleasures and pains \"stimulate the active machinery of the\nliving framework to perform such operations as procure the first and\nabate the last,\" then we must consider sneezing and coughing as examples\nof volition; and Mr. Bain surely cannot mean this. Indeed, we must\nconfess ourselves at a loss. On the one hand if he does not mean it, his\nexpression is lax to a degree that surprises us in so careful a writer.\nOn the other hand, if he does mean it, we cannot understand his point of\nview.\n\nA parallel criticism applies to his definition of Emotion. Here, too, he\nhas departed from the ordinary acceptation of the word; and, as we\nthink, in the wrong direction. Whatever may be the interpretation that\nis justified by its derivation, the word emotion has come generally to\nmean that kind of feeling which is not a direct result of any action on\nthe organism; but is either an indirect result of such action, or arises\nquite apart from such action. It is used to indicate those sentient\nstates which are independently generated in consciousness; as\ndistinguished from those generated in our corporeal framework, and known\nas sensations. Now this distinction, tacitly made in common speech, is\none which Psychology cannot well reject; but one which it must adopt,\nand to which it must give scientific precision. Mr. Bain, however,\nappears to ignore any such distinction. Under the term emotion, he\nincludes not only passions, sentiments, affections, but all \"feelings,\nstates of feeling, pleasures, pains,\"--that is, all sensations. This\ndoes not appear to be a mere lapse of expression; for when, in the\nopening sentence, he asserts that \"mind is comprised under the three\nheads--Emotion, Volition, and Intellect,\" he of necessity implies that\nsensation is included under one of these heads; and as it cannot be\nincluded under volition or intellect, it must be classed with emotion;\nas it clearly is in the next sentence.\n\nWe cannot but think this a retrograde step. Though distinctions which\nhave been established in popular thought and language, are not\nunfrequently merged in the higher generalizations of science (as, for\ninstance, when crabs and worms are grouped together in the sub-kingdom\n_Annulosa_); yet science very generally recognizes the validity of these\ndistinctions, as real though not fundamental. And so in the present\ncase. Such community as analysis discloses between sensation and\nemotion, must not shut out the broad contrast that exists between them.\nIf there needs a wider word, as there does, to signify any sentient\nstate whatever; then we may fitly adopt for this purpose the word\ncurrently so used, namely, \"Feeling.\" And considering as Feelings all\nthat great division of mental states which we do not class as\nCognitions, we may then separate this great division into the two\norders, Sensations and Emotions.\n\n       *       *       *       *       *\n\nAnd here we may, before concluding, briefly indicate the leading\noutlines of a classification which reduces this distinction to a\nscientific form, and develops it somewhat further--a classification\nwhich, while suggested by certain fundamental traits reached without a\nvery lengthened inquiry, is yet, we believe, in harmony with that\ndisclosed by detailed analysis.\n\nLeaving out of view the Will, which is a simple homogeneous mental\nstate, forming the link between feeling and action, and not admitting of\nsubdivisions; our states of consciousness fall into two great\nclasses--COGNITIONS and FEELINGS.\n\nCOGNITIONS, or those modes of mind in which we are occupied with the\n_relations_ that subsist among our feelings, are divisible into four\ngreat sub-classes.\n\n_Presentative cognitions_; or those in which consciousness is occupied\nin localizing a sensation impressed on the organism--occupied, that is,\nwith the relation between this presented mental state and those other\npresented mental states which make up our consciousness of the part\naffected: as when we cut ourselves.\n\n_Presentative-representative cognitions_; or those in which\nconsciousness is occupied with the relation between a sensation or group\nof sensations and the representations of those various other sensations\nthat accompany it in experience. This is what we commonly call\nperception--an act in which, along with certain impressions presented to\nconsciousness, there arise in consciousness the ideas of certain other\nimpressions ordinarily connected with the presented ones: as when its\nvisible form and colour, lead us to mentally endow an orange with all\nits other attributes.\n\n_Representative cognitions_; or those in which consciousness is occupied\nwith the relations among ideas or represented sensations; as in all acts\nof recollection.\n\n_Re-representative cognitions_; or those in which the occupation of\nconsciousness is not by representation of special relations that have\nbefore been presented to consciousness; but those in which such\nrepresented special relations are thought of merely as comprehended in a\ngeneral relation--those in which the concrete relations once\nexperienced, in so far as they become objects of consciousness at all,\nare incidentally represented, along with the abstract relation which\nformulates them. The ideas resulting from this abstraction, do not\nthemselves represent actual experiences; but are symbols which stand for\ngroups of such actual experiences--represent aggregates of\nrepresentations. And thus they may be called re-representative\ncognitions. It is clear that the process of re-representation is\ncarried to higher stages, as the thought becomes more abstract.\n\nFEELINGS, or those modes of mind in which we are occupied, not with the\nrelations subsisting between our sentient states, but with the sentient\nstates themselves, are divisible into four parallel sub-classes.\n\n_Presentative feelings_, ordinarily called sensations, are those mental\nstates in which, instead of regarding a corporeal impression as of this\nor that kind, or as located here or there, we contemplate it in itself\nas pleasure or pain: as when eating.\n\n_Presentative-representative feelings_, embracing a great part of what\nwe commonly call emotions, are those in which a sensation, or group of\nsensations, or group of sensations and ideas, arouses a vast aggregation\nof represented sensations; partly of individual experience, but chiefly\ndeeper than individual experience, and, consequently, indefinite. The\nemotion of terror may serve as an example. Along with certain\nimpressions made on the eyes or ears, or both, are recalled in\nconsciousness many of the pains to which such impressions have before\nbeen the antecedents; and when the relation between such impressions and\nsuch pains has been habitual in the race, the definite ideas of such\npains which individual experience has given, are accompanied by\nthe indefinite pains that result from inherited effects of\nexperiences--vague feelings which we may call organic representations.\nIn an infant, crying at a strange sight or sound while yet in the\nnurse's arms, we see these organic representations called into existence\nin the shape of dim discomfort, to which individual experience has yet\ngiven no specific outlines.\n\n_Representative feelings_, comprehending the ideas of the feelings above\nclassed, when they are called up apart from the appropriate external\nexcitements. As instances of these may be named the feelings with which\nthe descriptive poet writes, and which are aroused in the minds of his\nreaders.\n\n_Re-representative feelings_, under which head are included those more\ncomplex sentient states that are less the direct results of external\nexcitements than the indirect or reflex results of them. The love of\nproperty is a feeling of this kind. It is awakened not by the presence\nof any special object, but by ownable objects at large; and it is not\nfrom the mere presence of such object, but from a certain ideal relation\nto them, that it arises. As before shown (p. 253) it consists, not of\nthe represented advantages of possessing this or that, but of the\nrepresented advantages of possession in general--is not made up of\ncertain concrete representations, but of the abstracts of many concrete\nrepresentations; and so is re-representative. The higher sentiments, as\nthat of justice, are still more completely of this nature. Here the\nsentient state is compounded out of sentient states that are themselves\nwholly, or almost wholly, re-representative: it involves representations\nof those lower emotions which are produced by the possession of\nproperty, by freedom of action, etc.; and thus is re-representative in a\nhigher degree.\n\nThis classification, here roughly indicated and capable of further\nexpansion, will be found in harmony with the results of detailed\nanalysis aided by development. Whether we trace mental progression\nthrough the grades of the animal kingdom, through the grades of mankind,\nor through the stages of individual growth; it is obvious that the\nadvance, alike in cognitions and feelings, is, and must be, from the\npresentative to the more and more remotely representative. It is\nundeniable that intelligence ascends from those simple perceptions in\nwhich consciousness is occupied in localizing and classifying\nsensations, to perceptions more and more compound, to simple reasoning,\nto reasoning more and more complex and abstract--more and more remote\nfrom sensation. And in the evolution of feelings, there is a parallel\nseries of steps. Simple sensations; sensations combined together;\nsensations combined with represented sensations; represented sensations\norganized into groups, in which their separate characters are very much\nmerged; representations of these representative groups, in which the\noriginal components have become still more vague. In both cases, the\nprogress has necessarily been from the simple and concrete to the\ncomplex and abstract; and as with the cognitions, so with the feelings,\nthis must be the basis of classification.\n\nThe space here occupied with criticisms on Mr. Bain's work, we might\nhave filled with exposition and eulogy, had we thought this the more\nimportant. Though we have freely pointed out what we conceive to be its\ndefects, let it not be inferred that we question its great merits. We\nrepeat that, as a natural history of the mind, we believe it to be\nthe best yet produced. It is a most valuable collection of\ncarefully-elaborated materials. Perhaps we cannot better express our\nsense of its worth, than by saying that, to those who hereafter give to\nthis branch of Psychology a thoroughly scientific organization, Mr.\nBain's book will be indispensable.\n\n\n\n\nTHE SOCIAL ORGANISM.\n\n    [_First published in_ The Westminster Review _for January,_ 1860.]\n\n\nSir James Macintosh got great credit for the saying, that \"constitutions\nare not made, but grow.\" In our day, the most significant thing about\nthis saying is, that it was ever thought so significant. As from the\nsurprise displayed by a man at some familiar fact, you may judge of his\ngeneral culture; so from the admiration which an age accords to a new\nthought, its average degree of enlightenment may be inferred. That this\napophthegm of Macintosh should have been quoted and requoted as it has,\nshows how profound has been the ignorance of social science. A small ray\nof truth has seemed brilliant, as a distant rushlight looks like a star\nin the surrounding darkness.\n\nSuch a conception could not, indeed, fail to be startling when let fall\nin the midst of a system of thought to which it was utterly alien.\nUniversally in Macintosh's day, things were explained on the hypothesis\nof manufacture, rather than that of growth; as indeed they are, by the\nmajority, in our own day. It was held that the planets were severally\nprojected round the Sun from the Creator's hand, with just the velocity\nrequired to balance the Sun's attraction. The formation of the Earth,\nthe separation of sea from land, the production of animals, were\nmechanical works from which God rested as a labourer rests. Man was\nsupposed to be moulded after a manner somewhat akin to that in which a\nmodeller makes a clay-figure. And of course, in harmony with such\nideas, societies were tacitly assumed to be arranged thus or thus by\ndirect interposition of Providence; or by the regulations of law-makers;\nor by both.\n\nYet that societies are not artificially put together, is a truth so\nmanifest, that it seems wonderful men should ever have overlooked it.\nPerhaps nothing more clearly shows the small value of historical\nstudies, as they have been commonly pursued. You need but to look at the\nchanges going on around, or observe social organization in its leading\ntraits, to see that these are neither supernatural, nor are determined\nby the wills of individual men, as by implication the older historians\nteach; but are consequent on general natural causes. The one case of the\ndivision of labour suffices to prove this. It has not been by command of\nany ruler that some men have become manufacturers, while others have\nremained cultivators of the soil. In Lancashire, millions have devoted\nthemselves to the making of cotton-fabrics; in Yorkshire, another\nmillion lives by producing woollens; and the pottery of Staffordshire,\nthe cutlery of Sheffield, the hardware of Birmingham, severally occupy\ntheir hundreds of thousands. These are large facts in the structure of\nEnglish society; but we can ascribe them neither to miracle, nor to\nlegislation. It is not by \"the hero as king,\" any more than by\n\"collective wisdom,\" that men have been segregated into producers,\nwholesale distributors, and retail distributors. Our industrial\norganization, from its main outlines down to its minutest details, has\nbecome what it is, not simply without legislative guidance, but, to a\nconsiderable extent, in spite of legislative hindrances. It has arisen\nunder the pressure of human wants and resulting activities. While each\ncitizen has been pursuing his individual welfare, and none taking\nthought about division of labour, or conscious of the need of it,\ndivision of labour has yet been ever becoming more complete. It has been\ndoing this slowly and silently: few having observed it until quite\nmodern times. By steps so small, that year after year the industrial\narrangements have seemed just what they were before--by changes as\ninsensible as those through which a seed passes into a tree; society has\nbecome the complex body of mutually-dependent workers which we now see.\nAnd this economic organization, mark, is the all-essential organization.\nThrough the combination thus spontaneously evolved, every citizen is\nsupplied with daily necessaries; while he yields some product or aid to\nothers. That we are severally alive to-day, we owe to the regular\nworking of this combination during the past week; and could it be\nsuddenly abolished, multitudes would be dead before another week ended.\nIf these most conspicuous and vital arrangements of our social structure\nhave arisen not by the devising of any one, but through the individual\nefforts of citizens to satisfy their own wants; we may be tolerably\ncertain that the less important arrangements have similarly arisen.\n\n\"But surely,\" it will be said, \"the social changes directly produced by\nlaw, cannot be classed as spontaneous growths. When parliaments or kings\norder this or that thing to be done, and appoint officials to do it, the\nprocess is clearly artificial; and society to this extent becomes a\nmanufacture rather than a growth.\" No, not even these changes are\nexceptions, if they be real and permanent changes. The true sources of\nsuch changes lie deeper than the acts of legislators. To take first the\nsimplest instance. We all know that the enactments of representative\ngovernments ultimately depend on the national will: they may for a time\nbe out of harmony with it, but eventually they must conform to it. And\nto say that the national will finally determines them, is to say that\nthey result from the average of individual desires; or, in other\nwords--from the average of individual natures. A law so initiated,\ntherefore, really grows out of the popular character. In the case of a\nGovernment representing a dominant class, the same thing holds, though\nnot so manifestly. For the very existence of a class monopolizing all\npower, is due to certain sentiments in the commonalty. Without the\nfeeling of loyalty on the part of retainers, a feudal system could not\nexist. We see in the protest of the Highlanders against the abolition of\nheritable jurisdictions, that they preferred that kind of local rule.\nAnd if to the popular nature must be ascribed the growth of an\nirresponsible ruling class; then to the popular nature must be ascribed\nthe social arrangements which that class creates in the pursuit of its\nown ends. Even where the Government is despotic, the doctrine still\nholds. The character of the people is, as before, the original source of\nthis political form; and, as we have abundant proof, other forms\nsuddenly created will not act, but rapidly retrograde to the old form.\nMoreover, such regulations as a despot makes, if really operative, are\nso because of their fitness to the social state. His acts being very\nmuch swayed by general opinion--by precedent, by the feeling of his\nnobles, his priesthood, his army--are in part immediate results of the\nnational character; and when they are out of harmony with the national\ncharacter, they are soon practically abrogated. The failure of Cromwell\npermanently to establish a new social condition, and the rapid revival\nof suppressed institutions and practices after his death, show how\npowerless is a monarch to change the type of the society he governs. He\nmay disturb, he may retard, or he may aid the natural process of\norganization; but the general course of this process is beyond his\ncontrol. Nay, more than this is true. Those who regard the histories of\nsocieties as the histories of their great men, and think that these\ngreat men shape the fates of their societies, overlook the truth that\nsuch great men are the products of their societies. Without certain\nantecedents--without a certain average national character, they neither\ncould have been generated nor could have had the culture which formed\nthem. If their society is to some extent re-moulded by them, they\nwere, both before and after birth, moulded by their society--were the\nresults of all those influences which fostered the ancestral character\nthey inherited, and gave their own early bias, their creed, morals,\nknowledge, aspirations. So that such social changes as are immediately\ntraceable to individuals of unusual power, are still remotely traceable\nto the social causes which produced these individuals; and hence, from\nthe highest point of view, such social changes also, are parts of the\ngeneral developmental process.\n\nThus that which is so obviously true of the industrial structure of\nsociety, is true of its whole structure. The fact that \"constitutions\nare not made, but grow,\" is simply a fragment of the much larger fact,\nthat under all its aspects and through all its ramifications, society is\na growth and not a manufacture.\n\n       *       *       *       *       *\n\nA perception that there exists some analogy between the body politic and\na living individual body, was early reached; and has from time to time\nre-appeared in literature. But this perception was necessarily vague and\nmore or less fanciful. In the absence of physiological science, and\nespecially of those comprehensive generalizations which it has but\nlately reached, it was impossible to discern the real parallelisms.\n\nThe central idea of Plato's model Republic, is the correspondence\nbetween the parts of a society and the faculties of the human mind.\nClassifying these faculties under the heads of Reason, Will, and\nPassion, he classifies the members of his ideal society under what he\nregards as three analogous heads:--councillors, who are to exercise\ngovernment; military or executive, who are to fulfil their behests; and\nthe commonalty, bent on gain and selfish gratification. In other words,\nthe ruler, the warrior, and the craftsman, are, according to him, the\nanalogues of our reflective, volitional, and emotional powers. Now\neven were there truth in the implied assumption of a parallelism\nbetween the structure of a society and that of a man, this\nclassification would be indefensible. It might more truly be contended\nthat, as the military power obeys the commands of the Government, it is\nthe Government which answers to the Will; while the military power is\nsimply an agency set in motion by it. Or, again, it might be contended\nthat whereas the Will is a product of predominant desires, to which the\nReason serves merely as an eye, it is the craftsmen, who, according to\nthe alleged analogy, ought to be the moving power of the warriors.\n\nHobbes sought to establish a still more definite parallelism: not,\nhowever, between a society and the human mind, but between a society and\nthe human body. In the introduction to the work in which he develops\nthis conception, he says--\n\n     \"For by art is created that great LEVIATHAN called a COMMONWEALTH,\n     or STATE, in Latin CIVITAS, which is but an artificial man; though\n     of greater stature and strength than the natural, for whose\n     protection and defence it was intended, and in which the\n     _sovereignty_ is an artificial _soul_, as giving life and motion to\n     the whole body; the _magistrates_ and other _officers_ of\n     judicature and execution, artificial _joints_; _reward_ and\n     _punishment_, by which, fastened to the seat of the sovereignty,\n     every joint and member is moved to perform his duty, are the\n     _nerves_, that do the same in the body natural; the _wealth_ and\n     _riches_ of all the particular members are the _strength_; _salus\n     populi_, the _people's safety_, its _business_; _counsellors_, by\n     whom all things needful for it to know are suggested unto it, are\n     the _memory_; _equity_ and _laws_ an artificial _reason_ and\n     _will_; _concord_, _health_; _sedition_, _sickness_; and _civil\n     war_, _death_.\"\n\nAnd Hobbes carries this comparison so far as actually to give a drawing\nof the Leviathan--a vast human-shaped figure, whose body and limbs are\nmade up of multitudes of men. Just noting that these different analogies\nasserted by Plato and Hobbes, serve to cancel each other (being, as they\nare, so completely at variance), we may say that on the whole those of\nHobbes are the more plausible. But they are full of inconsistencies. If\nthe sovereignty is the _soul_ of the body-politic, how can it be that\nmagistrates, who are a kind of deputy-sovereigns, should be comparable\nto _joints_? Or, again, how can the three mental functions, memory,\nreason, and will, be severally analogous, the first to counsellors, who\nare a class of public officers, and the other two to equity and laws,\nwhich are not classes of officers, but abstractions? Or, once more, if\nmagistrates are the artificial joints of society, how can reward and\npunishment be its nerves? Its nerves must surely be some class of\npersons. Reward and punishment must in societies, as in individuals, be\n_conditions_ of the nerves, and not the nerves themselves.\n\nBut the chief errors of these comparisons made by Plato and Hobbes, lie\nmuch deeper. Both thinkers assume that the organization of a society is\ncomparable, not simply to the organization of a living body in general,\nbut to the organization of the human body in particular. There is no\nwarrant whatever for assuming this. It is in no way implied by the\nevidence; and is simply one of those fancies which we commonly find\nmixed up with the truths of early speculation. Still more erroneous are\nthe two conceptions in this, that they construe a society as an\nartificial structure. Plato's model republic--his ideal of a healthful\nbody-politic--is to be consciously put together by men, just as a watch\nmight be; and Plato manifestly thinks of societies in general as thus\noriginated. Quite specifically does Hobbes express a like view. \"For by\n_art_,\" he says, \"is created that great LEVIATHAN called a\nCOMMONWEALTH.\" And he even goes so far as to compare the supposed social\ncontract, from which a society suddenly originates, to the creation of a\nman by the divine fiat. Thus they both fall into the extreme\ninconsistency of considering a community as similar in structure to a\nhuman being, and yet as produced in the same way as an artificial\nmechanism--in nature, an organism; in history, a machine.\n\nNotwithstanding errors, however, these speculations have considerable\nsignificance. That such likenesses, crudely as they are thought out,\nshould have been alleged by Plato and Hobbes and others, is a reason\nfor suspecting that _some_ analogy exists. The untenableness of the\nparticular parallelisms above instanced, is no ground for denying an\nessential parallelism; since early ideas are usually but vague\nadumbrations of the truth. Lacking the great generalizations of biology,\nit was, as we have said, impossible to trace out the real relations of\nsocial organizations to organizations of another order. We propose here\nto show what are the analogies which modern science discloses.\n\n       *       *       *       *       *\n\nLet us set out by succinctly stating the points of similarity and the\npoints of difference. Societies agree with individual organisms in four\nconspicuous peculiarities:--\n\n1. That commencing as small aggregations, they insensibly augment in\nmass: some of them eventually reaching ten thousand times what they\noriginally were.\n\n2. That while at first so simple in structure as to be considered\nstructureless, they assume, in the course of their growth, a\ncontinually-increasing complexity of structure.\n\n3. That though in their early, undeveloped states, there exists in them\nscarcely any mutual dependence of parts, their parts gradually acquire a\nmutual dependence; which becomes at last so great, that the activity and\nlife of each part is made possible only by the activity and life of the\nrest.\n\n4. That the life of a society is independent of, and far more prolonged\nthan, the lives of any of its component units; who are severally born,\ngrow, work, reproduce, and die, while the body-politic composed of them\nsurvives generation after generation, increasing in mass, in\ncompleteness of structure, and in functional activity.\n\nThese four parallelisms will appear the more significant the more we\ncontemplate them. While the points specified, are points in which\nsocieties agree with individual organisms, they are also points in which\nindividual organisms agree with one another, and disagree with all\nthings else. In the course of its existence, every plant and animal\nincreases in mass, in a way not paralleled by inorganic objects: even\nsuch inorganic objects as crystals, which arise by growth, show us no\nsuch definite relation between growth and existence as organisms do. The\norderly progress from simplicity to complexity, displayed by\nbodies-politic in common with living bodies, is a characteristic which\ndistinguishes living bodies from the inanimate bodies amid which they\nmove. That functional dependence of parts, which is scarcely more\nmanifest in animals than in nations, has no counterpart elsewhere. And\nin no aggregate except an organic or a social one, is there a perpetual\nremoval and replacement of parts, joined with a continued integrity of\nthe whole. Moreover, societies and organisms are not only alike in these\npeculiarities, in which they are unlike all other things; but the\nhighest societies, like the highest organisms, exhibit them in the\ngreatest degree. We see that the lowest animals do not increase to\nanything like the sizes of the higher ones; and, similarly, we see that\naboriginal societies are comparatively limited in their growths. In\ncomplexity, our large civilized nations as much exceed primitive savage\ntribes, as a mammal does a zoophyte. Simple communities, like simple\ncreatures, have so little mutual dependence of parts, that mutilation or\nsubdivision causes but little inconvenience; but from complex\ncommunities, as from complex creatures, you cannot remove any\nconsiderable organ without producing great disturbance or death of the\nrest. And in societies of low type, as in inferior animals, the life of\nthe aggregate, often cut short by division or dissolution, exceeds in\nlength the lives of the component units, very far less than in civilized\ncommunities and superior animals; which outlive many generations of\ntheir component units.\n\nOn the other hand, the leading differences between societies and\nindividual organisms are these:--\n\n1. That societies have no specific external forms. This, however, is a\npoint of contrast which loses much of its importance, when we remember\nthat throughout the vegetal kingdom, as well as in some lower divisions\nof the animal kingdom, the forms are often very indefinite--definiteness\nbeing rather the exception than the rule; and that they are manifestly\nin part determined by surrounding physical circumstances, as the forms\nof societies are. If, too, it should eventually be shown, as we believe\nit will, that the form of every species of organism has resulted from\nthe average play of the external forces to which it has been subject\nduring its evolution as a species; then, that the external forms of\nsocieties should depend, as they do, on surrounding conditions, will be\na further point of community.\n\n2. That though the living tissue whereof an individual organism\nconsists, forms a continuous mass, the living elements of a society do\nnot form a continuous mass; but are more or less widely dispersed over\nsome portion of the Earth's surface. This, which at first sight appears\nto be an absolute distinction, is one which yet to a great extent fades\nwhen we contemplate all the facts. For, in the lower divisions of the\nanimal and vegetal kingdoms, there are types of organization much more\nnearly allied, in this respect, to the organization of a society, than\nmight be supposed--types in which the living units essentially composing\nthe mass, are dispersed through an inert substance, that can scarcely be\ncalled living in the full sense of the word. It is thus with some of the\n_Protococci_ and with the _Nostoceae_, which exist as cells imbedded in a\nviscid matter. It is so, too, with the _Thalassicollae_--bodies made up\nof differentiated parts, dispersed through an undifferentiated jelly.\nAnd throughout considerable portions of their bodies, some of the\n_Acalephae_ exhibit more or less this type of structure. Now this is very\nmuch the case with a society. For we must remember that though the men\nwho make up a society are physically separate, and even scattered, yet\nthe surface over which they are scattered is not one devoid of life, but\nis covered by life of a lower order which ministers to their life. The\nvegetation which clothes a country makes possible the animal life in\nthat country; and only through its animal and vegetal products can such\na country support a society. Hence the members of the body-politic are\nnot to be regarded as separated by intervals of dead space, but as\ndiffused through a space occupied by life of a lower order. In our\nconception of a social organism, we must include all that lower organic\nexistence on which human existence, and therefore social existence,\ndepend. And when we do this, we see that the citizens who make up a\ncommunity may be considered as highly vitalized units surrounded by\nsubstances of lower vitality, from which they draw their nutriment: much\nas in the cases above instanced.\n\n3. The third difference is that while the ultimate living elements of an\nindividual organism are mostly fixed in their relative positions, those\nof the social organism are capable of moving from place to place. But\nhere, too, the disagreement is much less than would be supposed. For\nwhile citizens are locomotive in their private capacities, they are\nfixed in their public capacities. As farmers, manufacturers, or traders,\nmen carry on their businesses at the same spots, often throughout their\nwhole lives; and if they go away occasionally, they leave behind others\nto discharge their functions in their absence. Each great centre of\nproduction, each manufacturing town or district, continues always in the\nsame place; and many of the firms in such town or district, are for\ngenerations carried on either by the descendants or successors of those\nwho founded them. Just as in a living body, the cells that make up some\nimportant organ severally perform their functions for a time and then\ndisappear, leaving others to supply their places; so, in each part of a\nsociety the organ remains, though the persons who compose it change.\nThus, in social life, as in the life of an animal, the units as well as\nthe larger agencies formed of them, are in the main stationary as\nrespects the places where they discharge their duties and obtain their\nsustenance. And hence the power of individual locomotion does not\npractically affect the analogy.\n\n4. The last and perhaps the most important distinction is, that while in\nthe body of an animal only a special tissue is endowed with feeling, in\na society all the members are endowed with feeling. Even this\ndistinction, however, is not a complete one. For in some of the lowest\nanimals, characterized by the absence of a nervous system, such\nsensitiveness as exists is possessed by all parts. It is only in the\nmore organized forms that feeling is monopolized by one class of the\nvital elements. And we must remember that societies, too, are not\nwithout a certain differentiation of this kind. Though the units of a\ncommunity are all sensitive, they are so in unequal degrees. The classes\nengaged in laborious occupations are less susceptible, intellectually\nand emotionally, than the rest; and especially less so than the classes\nof highest mental culture. Still, we have here a tolerably decided\ncontrast between bodies-politic and individual bodies; and it is one\nwhich we should keep constantly in view. For it reminds us that while,\nin individual bodies, the welfare of all other parts is rightly\nsubservient to the welfare of the nervous system, whose pleasurable or\npainful activities make up the good or ill of life; in bodies-politic\nthe same thing does not hold, or holds to but a very slight extent. It\nis well that the lives of all parts of an animal should be merged in the\nlife of the whole, because the whole has a corporate consciousness\ncapable of happiness or misery. But it is not so with a society; since\nits living units do not and cannot lose individual consciousness, and\nsince the community as a whole has no corporate consciousness. This is\nan everlasting reason why the welfares of citizens cannot rightly be\nsacrificed to some supposed benefit of the State, and why, on the other\nhand, the State is to be maintained solely for the benefit of\ncitizens. The corporate life must here be subservient to the lives of\nthe parts, instead of the lives of the parts being subservient to the\ncorporate life.\n\nSuch, then, are the points of analogy and the points of difference. May\nwe not say that the points of difference serve but to bring into clearer\nlight the points of analogy? While comparison makes definite the obvious\ncontrasts between organisms commonly so called, and the social organism,\nit shows that even these contrasts are not so decided as was to be\nexpected. The indefiniteness of form, the discontinuity of the parts,\nand the universal sensitiveness, are not only peculiarities of the\nsocial organism which have to be stated with considerable\nqualifications; but they are peculiarities to which the inferior classes\nof animals present approximations. Thus we find but little to conflict\nwith the all-important analogies. Societies slowly augment in mass; they\nprogress in complexity of structure; at the same time their parts become\nmore mutually dependent; their living units are removed and replaced\nwithout destroying their integrity; and the extents to which they\ndisplay these peculiarities are proportionate to their vital activities.\nThese are traits that societies have in common with organic bodies. And\nthese traits in which they agree with organic bodies and disagree with\nall other things, entirely subordinate the minor distinctions: such\ndistinctions being scarcely greater than those which separate one half\nof the organic kingdom from the other. The _principles_ of organization\nare the same, and the differences are simply differences of application.\n\nHere ending this general survey of the facts which justify the\ncomparison of a society with a living body, let us look at them in\ndetail. We shall find that the parallelism becomes the more marked the\nmore closely it is examined.\n\n       *       *       *       *       *\n\nThe lowest animal and vegetal forms--_Protozoa_ and _Protophyta_--are\nchiefly inhabitants of the water. They are minute bodies, most of which\nare made individually visible only by the microscope. All of them are\nextremely simple in structure, and some of them, as the _Rhizopods_,\nalmost structureless. Multiplying, as they ordinarily do, by the\nspontaneous division of their bodies, they produce halves which may\neither become quite separate and move away in different directions, or\nmay continue attached. By the repetition of this process of fission,\naggregations of various sizes and kinds are formed. Among the\n_Protophyta_ we have some classes, as the _Diatomaceae_ and the\nYeast-plant, in which the individuals may be either separate or attached\nin groups of two, three, four, or more; other classes in which a\nconsiderable number of cells are united into a thread (_Conferva_,\n_Monilia_); others in which they form a network (_Hydrodictyon_); others\nin which they form plates (_Ulva_); and others in which they form masses\n(_Laminaria_, _Agaricus_): all which vegetal forms, having no\ndistinction of root, stem, or leaf, are called _Thallogens_. Among the\n_Protozoa_ we find parallel facts. Immense numbers of _Amoeba_-like\ncreatures, massed together in a framework of horny fibres, constitute\nSponge. In the _Foraminifera_ we see smaller groups of such creatures\narranged into more definite shapes. Not only do these almost\nstructureless _Protozoa_ unite into regular or irregular aggregations of\nvarious sizes, but among some of the more organized ones, as the\n_Vorticellae_, there are also produced clusters of individuals united to\na common stem. But these little societies of monads, or cells, or\nwhatever else we may call them, are societies only in the lowest sense:\nthere is no subordination of parts among them--no organization. Each of\nthe component units lives by and for itself; neither giving nor\nreceiving aid. The only mutual dependence is that consequent on\nmechanical union.\n\nDo we not here discern analogies to the first stages of human societies?\nAmong the lowest races, as the Bushmen, we find but incipient\naggregation: sometimes single families, sometimes two or three families\nwandering about together. The number of associated units is small and\nvariable, and their union inconstant. No division of labour exists\nexcept between the sexes, and the only kind of mutual aid is that of\njoint attack or defence. We see an undifferentiated group of\nindividuals, forming the germ of a society; just as in the homogeneous\ngroups of cells above described, we see the initial stage of animal and\nvegetal organization.\n\nThe comparison may now be carried a step higher. In the vegetal kingdom\nwe pass from the _Thallogens_, consisting of mere masses of similar\ncells, to the _Acrogens_, in which the cells are not similar throughout\nthe whole mass; but are here aggregated into a structure serving as leaf\nand there into a structure serving as root; thus forming a whole in\nwhich there is a certain subdivision of functions among the units, and\ntherefore a certain mutual dependence. In the animal kingdom we find\nanalogous progress. From mere unorganized groups of cells, or cell-like\nbodies, we ascend to groups of such cells arranged into parts that have\ndifferent duties. The common Polype, from the substance of which may be\nseparated cells that exhibit, when detached, appearances and movements\nlike those of a solitary _Amoeba_, illustrates this stage. The\ncomponent units, though still showing great community of character,\nassume somewhat diverse functions in the skin, in the internal surface,\nand in the tentacles. There is a certain amount of \"physiological\ndivision of labour.\"\n\nTurning to societies, we find these stages paralleled in most aboriginal\ntribes. When, instead of such small variable groups as are formed by\nBushmen, we come to the larger and more permanent groups formed by\nsavages not quite so low, we find traces of social structure. Though\nindustrial organization scarcely shows itself, except in the different\noccupations of the sexes; yet there is more or less of governmental\norganization. While all the men are warriors and hunters, only a part\nof them are included in the council of chiefs; and in this council of\nchiefs some one has commonly supreme authority. There is thus a certain\ndistinction of classes and powers; and through this slight\nspecialization of functions is effected a rude co-operation among the\nincreasing mass of individuals, whenever the society has to act in its\ncorporate capacity. Beyond this analogy in the slight extent to which\norganization is carried, there is analogy in the indefiniteness of the\norganization. In the _Hydra_, the respective parts of the creature's\nsubstance have many functions in common. They are all contractile;\nomitting the tentacles, the whole of the external surface can give\norigin to young _hydrae_; and, when turned inside out, stomach performs\nthe duties of skin and skin the duties of stomach. In aboriginal\nsocieties such differentiations as exist are similarly imperfect.\nNotwithstanding distinctions of rank, all persons maintain themselves by\ntheir own exertions. Not only do the head men of the tribe, in common\nwith the rest, build their own huts, make their own weapons, kill their\nown food; but the chief does the like. Moreover, such governmental\norganization as exists is inconstant. It is frequently changed by\nviolence or treachery, and the function of ruling assumed by some other\nwarrior. Thus between the rudest societies and some of the lowest forms\nof animal life, there is analogy alike in the slight extent to which\norganization is carried, in the indefiniteness of this organization, and\nin its want of fixity.\n\nA further complication of the analogy is at hand. From the aggregation\nof units into organized groups, we pass to the multiplication of such\ngroups, and their coalescence into compound groups. The _Hydra_, when it\nhas reached a certain bulk, puts forth from its surface a bud which,\ngrowing and gradually assuming the form of the parent, finally becomes\ndetached; and by this process of gemmation the creature peoples the\nadjacent water with others like itself. A parallel process is seen in\nthe multiplication of those lowly-organized tribes above described. When\none of them has increased to a size that is either too great for\nco-ordination under so rude a structure, or else that is greater than\nthe surrounding country can supply with game and other wild food, there\narises a tendency to divide; and as in such communities there often\noccur quarrels, jealousies, and other causes of division, there soon\ncomes an occasion on which a part of the tribe separates under the\nleadership of some subordinate chief and migrates. This process being\nfrom time to time repeated, an extensive region is at length occupied by\nnumerous tribes descended from a common ancestry. The analogy by no\nmeans ends here. Though in the common _Hydra_ the young ones that bud\nout from the parent soon become detached and independent; yet throughout\nthe rest of the class _Hydrozoa_, to which this creature belongs, the\nlike does not generally happen. The successive individuals thus\ndeveloped continue attached; give origin to other such individuals which\nalso continue attached; and so there results a compound animal. As in\nthe _Hydra_ itself we find an aggregation of units which, considered\nseparately, are akin to the lowest _Protozoa_; so here, in a _Zoophyte_,\nwe find an aggregation of such aggregations. The like is also seen\nthroughout the extensive family of _Polyzoa_ or _Molluscoida_. The\nAscidian Mollusks, too, in their many forms, show us the same thing:\nexhibiting, at the same time, various degrees of union among the\ncomponent individuals. For while in the _Salpae_ the component\nindividuals adhere so slightly that a blow on the vessel of water in\nwhich they are floating will separate them; in the _Botryllidae_ there\nexist vascular connexions among them, and a common circulation. Now in\nthese different stages of aggregation, may we not see paralleled the\nunion of groups of connate tribes into nations? Though, in regions where\ncircumstances permit, the tribes descended from some original tribe\nmigrate in all directions, and become far removed and quite separate;\nyet, where the territory presents barriers to distant migration, this\ndoes not happen: the small kindred communities are held in closer\ncontact, and eventually become more or less united into a nation. The\ncontrast between the tribes of American Indians and the Scottish clans,\nillustrates this. And a glance at our own early history, or the early\nhistories of continental nations, shows this fusion of small simple\ncommunities taking place in various ways and to various extents. As says\nM. Guizot, in his _History of the Origin of Representative\nGovernment_,--\n\n     \"By degrees, in the midst of the chaos of the rising society, small\n     aggregations are formed which feel the want of alliance and union\n     with each other.... Soon inequality of strength is displayed among\n     neighbouring aggregations. The strong tend to subjugate the weak,\n     and usurp at first the rights of taxation and military service.\n     Thus political authority leaves the aggregations which first\n     instituted it, to take a wider range.\"\n\nThat is to say, the small tribes, clans, or feudal groups, sprung mostly\nfrom a common stock, and long held in contact as occupants of adjacent\nlands, gradually get united in other ways than by kinship and proximity.\n\nA further series of changes begins now to take place, to which, as\nbefore, we find analogies in individual organisms. Returning to the\n_Hydrozoa_, we observe that in the simplest of the compound forms the\nconnected individuals are alike in structure, and perform like\nfunctions; with the exception that here and there a bud, instead of\ndeveloping into a stomach, mouth, and tentacles, becomes an egg-sac. But\nwith the oceanic _Hydrozoa_ this is by no means the case. In the\n_Calycophoridae_ some of the polypes growing from the common germ, become\ndeveloped and modified into large, long, sack-like bodies, which, by\ntheir rhythmical contractions, move through the water, dragging the\ncommunity of polypes after them. In the _Physophoridae_ a variety of\norgans similarly arise by transformation of the budding polypes; so that\nin creatures like the _Physalia_, commonly known as the \"Portuguese\nMan-of-war,\" instead of that tree-like group of similar individuals\nforming the original type, we have a complex mass of unlike parts\nfulfilling unlike duties. As an individual _Hydra_ may be regarded as a\ngroup of _Protozoa_ which have become partially metamorphosed into\ndifferent organs; so a _Physalia_ is, morphologically considered, a\ngroup of _Hydrae_ of which the individuals have been variously\ntransformed to fit them for various functions.\n\nThis differentiation upon differentiation is just what takes place\nduring the evolution of a civilized society. We observed how, in the\nsmall communities first formed, there arises a simple political\norganization: there is a partial separation of classes having different\nduties. And now we have to observe how, in a nation formed by the fusion\nof such small communities, the several sections, at first alike in\nstructures and modes of activity, grow unlike in both--gradually become\nmutually-dependent parts, diverse in their natures and functions.\n\n       *       *       *       *       *\n\nThe doctrine of the progressive division of labour, to which we are here\nintroduced, is familiar to all readers. And further, the analogy between\nthe economical division of labour and the \"physiological division of\nlabour,\" is so striking as long since to have drawn the attention of\nscientific naturalists: so striking, indeed, that the expression\n\"physiological division of labour,\" has been suggested by it. It is not\nneedful, therefore, to treat this part of the subject in great detail.\nWe shall content ourselves with noting a few general and significant\nfacts, not manifest on a first inspection.\n\nThroughout the whole animal kingdom, from the _Coelenterata_ upwards,\nthe first stage of evolution is the same. Equally in the germ of a\npolype and in the human ovum, the aggregated mass of cells out of which\nthe creature is to arise, gives origin to a peripheral layer of cells,\nslightly differing from the rest which they include; and this layer\nsubsequently divides into two--the inner, lying in contact with the\nincluded yelk, being called the mucous layer, and the outer, exposed to\nsurrounding agencies, being called the serous layer: or, in the terms\nused by Prof. Huxley, in describing the development of the\n_Hydrozoa_--the endoderm and ectoderm. This primary division marks out a\nfundamental contrast of parts in the future organism. From the mucous\nlayer, or endoderm, is developed the apparatus of nutrition; while from\nthe serous layer, or ectoderm, is developed the apparatus of external\naction. Out of the one arise the organs by which food is prepared and\nabsorbed, oxygen imbibed, and blood purified; while out of the other\narise the nervous, muscular, and osseous systems, by the combined\nactions of which the movements of the body as a whole are effected.\nThough this is not a rigorously-correct distinction, seeing that some\norgans involve both of these primitive membranes, yet high authorities\nagree in stating it as a broad general distinction. Well, in the\nevolution of a society, we see a primary differentiation of analogous\nkind, which similarly underlies the whole future structure. As already\npointed out, the only manifest contrast of parts in primitive societies,\nis that between the governing and the governed. In the least organized\ntribes, the council of chiefs may be a body of men distinguished simply\nby greater courage or experience. In more organized tribes, the\nchief-class is definitely separated from the lower class, and often\nregarded as different in nature--sometimes as god-descended. And later,\nwe find these two becoming respectively freemen and slaves, or nobles\nand serfs. A glance at their respective functions, makes it obvious that\nthe great divisions thus early formed, stand to each other in a relation\nsimilar to that in which the primary divisions of the embryo stand to\neach other. For, from its first appearance, the warrior-class, headed by\nchiefs, is that by which the external acts of the society are carried\non: alike in war, in negotiation, and in migration. Afterwards, while\nthis upper class grows distinct from the lower, and at the same time\nbecomes more and more exclusively regulative and defensive in its\nfunctions, alike in the persons of kings and subordinate rulers,\npriests, and soldiers; the inferior class becomes more and more\nexclusively occupied in providing the necessaries of life for the\ncommunity at large. From the soil, with which it comes in most direct\ncontact, the mass of the people takes up, and prepares for use, the food\nand such rude articles of manufacture as are known; while the overlying\nmass of superior men, maintained by the working population, deals with\ncircumstances external to the community--circumstances with which, by\nposition, it is more immediately concerned. Ceasing by-and-by to have\nany knowledge of, or power over, the concerns of the society as a whole,\nthe serf-class becomes devoted to the processes of alimentation; while\nthe noble class, ceasing to take any part in the processes of\nalimentation, becomes devoted to the co-ordinated movements of the\nentire body-politic.\n\nEqually remarkable is a further analogy of like kind. After the mucous\nand serous layers of the embryo have separated, there presently arises\nbetween the two a third, known to physiologists as the vascular layer--a\nlayer out of which are developed the chief blood-vessels. The mucous\nlayer absorbs nutriment from the mass of yelk it encloses; this\nnutriment has to be transferred to the overlying serous layer, out of\nwhich the nervo-muscular system is being developed; and between the two\narises a vascular system by which the transfer is effected--a system of\nvessels which continues ever after to be the transferrer of nutriment\nfrom the places where it is absorbed and prepared, to the places where\nit is needed for growth and repair. Well, may we not trace a parallel\nstep in social progress? Between the governing and the governed, there\nat first exists no intermediate class; and even in some societies that\nhave reached considerable sizes, there are scarcely any but the nobles\nand their kindred on the one hand, and the serfs on the other: the\nsocial structure being such that transfer of commodities takes place\ndirectly from slaves to their masters. But in societies of a higher\ntype, there grows up, between these two primitive classes, another--the\ntrading or middle class. Equally at first as now, we may see that,\nspeaking generally, this middle class is the analogue of the middle\nlayer in the embryo. For all traders are essentially distributors.\nWhether they be wholesale dealers, who collect into large masses the\ncommodities of various producers; or whether they be retailers, who\ndivide out to those who want them, the masses of commodities thus\ncollected together; all mercantile men are agents of transfer from the\nplaces where things are produced to the places where they are consumed.\nThus the distributing apparatus in a society, answers to the\ndistributing apparatus in a living body; not only in its functions, but\nin its intermediate origin and subsequent position, and in the time of\nits appearance.\n\nWithout enumerating the minor differentiations which these three great\nclasses afterwards undergo, we will merely note that throughout, they\nfollow the same general law with the differentiations of an individual\norganism. In a society, as in a rudimentary animal, we have seen that\nthe most general and broadly contrasted divisions are the first to make\ntheir appearance; and of the subdivisions it continues true in both\ncases, that they arise in the order of decreasing generality.\n\nLet us observe, next, that in the one case as in the other, the\nspecializations are at first very incomplete, and approach completeness\nas organization progresses. We saw that in primitive tribes, as in the\nsimplest animals, there remains much community of function between the\nparts which are nominally different--that, for instance, the class of\nchiefs long remains industrially the same as the inferior class; just\nas in a _Hydra_, the property of contractility is possessed by the units\nof the endoderm as well as by those of the ectoderm. We noted also how,\nas the society advanced, the two great primitive classes partook less\nand less of each other's functions. And we have here to remark that all\nsubsequent specializations are at first vague and gradually become\ndistinct. \"In the infancy of society,\" says M. Guizot, \"everything is\nconfused and uncertain; there is as yet no fixed and precise line of\ndemarcation between the different powers in a state.\" \"Originally kings\nlived like other landowners, on the incomes derived from their own\nprivate estates.\" Nobles were petty kings; and kings only the most\npowerful nobles. Bishops were feudal lords and military leaders. The\nright of coining money was possessed by powerful subjects, and by the\nChurch, as well as by the king. Every leading man exercised alike the\nfunctions of landowner, farmer, soldier, statesman, judge. Retainers\nwere now soldiers, and now labourers, as the day required. But by\ndegrees the Church has lost all civil jurisdiction; the State has\nexercised less and less control over religious teaching; the military\nclass has grown a distinct one; handicrafts have concentrated in towns;\nand the spinning-wheels of scattered farmhouses, have disappeared before\nthe machinery of manufacturing districts. Not only is all progress from\nthe homogeneous to the heterogeneous, but, at the same time, it is from\nthe indefinite to the definite.\n\nAnother fact which should not be passed over, is that in the evolution\nof a large society out of a cluster of small ones, there is a gradual\nobliteration of the original lines of separation--a change to which,\nalso, we may see analogies in living bodies. The sub-kingdom _Annulosa_,\nfurnishes good illustrations. Among the lower types the body consists of\nnumerous segments that are alike in nearly every particular. Each has\nits external ring; its pair of legs, if the creature has legs; its\nequal portion of intestine, or else its separate stomach; its equal\nportion of the great blood-vessel, or, in some cases, its separate\nheart; its equal portion of the nervous cord; and, perhaps, its separate\npair of ganglia. But in the highest types, as in the large _Crustacea_,\nmany of the segments are completely fused together; and the internal\norgans are no longer uniformly repeated in all the segments. Now the\nsegments of which nations at first consist, lose their separate external\nand internal structures in a similar manner. In feudal times the minor\ncommunities, governed by feudal lords, were severally organized in the\nsame rude way, and were held together only by the fealty of their\nrespective rulers to a suzerain. But along with the growth of a central\npower, the demarcations of these local communities become relatively\nunimportant, and their separate organizations merge into the general\norganization. The like is seen on a larger scale in the fusion of\nEngland, Wales, Scotland, and Ireland; and, on the Continent, in the\ncoalescence of provinces into kingdoms. Even in the disappearance of\nlaw-made divisions, the process is analogous. Among the Anglo-Saxons,\nEngland was divided into tithings, hundreds, and counties: there were\ncounty-courts, courts of hundred, and courts of tithing. The courts of\ntithing disappeared first; then the courts of hundred, which have,\nhowever, left traces; while the county-jurisdiction still exists.\nChiefly, however, it is to be noted, that there eventually grows up an\norganization which has no reference to these original divisions, but\ntraverses them in various directions, as is the case in creatures\nbelonging to the sub-kingdom just named; and, further, that in both\ncases it is the sustaining organization which thus traverses old\nboundaries, while, in both cases, it is the governmental, or\nco-ordinating organization in which the original boundaries continue\ntraceable. Thus, in the highest _Annulosa_ the exo-skeleton and the\nmuscular system never lose all traces of their primitive segmentation;\nbut throughout a great part of the body, the contained viscera do not in\nthe least conform to the external divisions. Similarly with a nation we\nsee that while, for governmental purposes, such divisions as counties\nand parishes still exist, the structure developed for carrying on the\nnutrition of society wholly ignores these boundaries: our great\ncotton-manufacture spreads out of Lancashire into North Derbyshire;\nLeicestershire and Nottinghamshire have long divided the stocking-trade\nbetween them; one great centre for the production of iron and\niron-goods, includes parts of Warwickshire, Staffordshire, and\nWorcestershire; and those various specializations of agriculture which\nhave made different parts of England noted for different products, show\nno more respect to county-boundaries than do our growing towns to the\nboundaries of parishes.\n\nIf, after contemplating these analogies of structure, we inquire whether\nthere are any such analogies between the processes of organic change,\nthe answer is--yes. The causes which lead to increase of bulk in any\npart of the body-politic, are of like nature with those which lead to\nincrease of bulk in any part of an individual body. In both cases the\nantecedent is greater functional activity consequent on greater demand.\nEach limb, viscus, gland, or other member of an animal, is developed by\nexercise--by actively discharging the duties which the body at large\nrequires of it; and similarly, any class of labourers or artisans, any\nmanufacturing centre, or any official agency, begins to enlarge when the\ncommunity devolves on it more work. In each case, too, growth has its\nconditions and its limits. That any organ in a living being may grow by\nexercise, there needs a due supply of blood. All action implies waste;\nblood brings the materials for repair; and before there can be growth,\nthe quantity of blood supplied must be more than is requisite for\nrepair. In a society it is the same. If to some district which\nelaborates for the community particular commodities--say the woollens\nof Yorkshire--there comes an augmented demand; and if, in fulfilment of\nthis demand, a certain expenditure and wear of the manufacturing\norganization are incurred; and if, in payment for the extra quantity of\nwoollens sent away, there comes back only such quantity of commodities\nas replaces the expenditure, and makes good the waste of life and\nmachinery; there can clearly be no growth. That there may be growth, the\ncommodities obtained in return must be more than sufficient for these\nends; and just in proportion as the surplus is great will the growth be\nrapid. Whence it is manifest that what in commercial affairs we call\n_profit_, answers to the excess of nutrition over waste in a living\nbody. Moreover, in both cases when the functional activity is high and\nthe nutrition defective, there results not growth but decay. If in an\nanimal, any organ is worked so hard that the channels which bring blood\ncannot furnish enough for repair, the organ dwindles: atrophy is set up.\nAnd if in the body-politic, some part has been stimulated into great\nproductivity, and cannot afterwards get paid for all its produce,\ncertain of its members become bankrupt, and it decreases in size.\n\nOne more parallelism to be here noted, is that the different parts of a\nsocial organism, like the different parts of an individual organism,\ncompete for nutriment; and severally obtain more or less of it according\nas they are discharging more or less duty. If a man's brain be\noverexcited it abstracts blood from his viscera and stops digestion; or\ndigestion, actively going on, so affects the circulation through the\nbrain as to cause drowsiness; or great muscular exertion determines such\na quantity of blood to the limbs as to arrest digestion or cerebral\naction, as the case may be. So, likewise, in a society, great activity\nin some one direction causes partial arrests of activity elsewhere by\nabstracting capital, that is commodities: as instance the way in which\nthe sudden development of our railway-system hampered commercial\noperations; or the way in which the raising of a large military force\ntemporarily stops the growth of leading industries.\n\n       *       *       *       *       *\n\nThe last few paragraphs introduce the next division of our subject.\nAlmost unawares we have come upon the analogy which exists between the\nblood of a living body and the circulating mass of commodities in the\nbody-politic. We have now to trace out this analogy from its simplest to\nits most complex manifestations.\n\nIn the lowest animals there exists no blood properly so called. Through\nthe small assemblage of cells which make up a _Hydra_, permeate the\njuices absorbed from the food. There is no apparatus for elaborating a\nconcentrated and purified nutriment, and distributing it among the\ncomponent units; but these component units directly imbibe the\nunprepared nutriment, either from the digestive cavity or from one\nanother. May we not say that this is what takes place in an aboriginal\ntribe? All its members severally obtain for themselves the necessaries\nof life in their crude states; and severally prepare them for their own\nuses as well as they can. When there arises a decided differentiation\nbetween the governing and the governed, some amount of transfer begins\nbetween those inferior individuals who, as workers, come directly in\ncontact with the products of the earth, and those superior ones who\nexercise the higher functions--a transfer parallel to that which\naccompanies the differentiation of the ectoderm from the endoderm. In\nthe one case, as in the other, however, it is a transfer of products\nthat are little if at all prepared; and takes place directly from the\nunit which obtains to the unit which consumes, without entering into any\ngeneral current.\n\nPassing to larger organisms--individual and social--we meet the first\nadvance on this arrangement. Where, as among the compound _Hydrozoa_,\nthere is a union of many such primitive groups as form _Hydrae_; or\nwhere, as in a _Medusa_, one of these groups has become of great size;\nthere exist rude channels running throughout the substance of the body:\nnot, however, channels for the conveyance of prepared nutriment, but\nmere prolongations of the digestive cavity, through which the crude\nchyle-aqueous fluid reaches the remoter parts, and is moved backwards\nand forwards by the creature's contractions. Do we not find in some of\nthe more advanced primitive communities an analogous condition? When the\nmen, partially or fully united into one society, become numerous--when,\nas usually happens, they cover a surface of country not everywhere alike\nin its products--when, more especially, there arise considerable classes\nwhich are not industrial; some process of exchange and distribution\ninevitably arises. Traversing here and there the earth's surface,\ncovered by that vegetation on which human life depends, and in which, as\nwe say, the units of a society are imbedded, there are formed indefinite\npaths, along which some of the necessaries of life occasionally pass, to\nbe bartered for others which presently come back along the same\nchannels. Note, however, that at first little else but crude commodities\nare thus transferred--fruits, fish, pigs or cattle, skins, etc.: there\nare few, if any, manufactured products or articles prepared for\nconsumption. And note also, that such distribution of these unprepared\nnecessaries of life as takes place, is but occasional--goes on with a\ncertain slow, irregular rhythm.\n\nFurther progress in the elaboration and distribution of nutriment, or of\ncommodities, is a necessary accompaniment of further differentiation of\nfunctions in the individual body or in the body-politic. As fast as each\norgan of a living animal becomes confined to a special action, it must\nbecome dependent on the rest for those materials which its position and\nduty do not permit it to obtain for itself; in the same way that, as\nfast as each particular class of a community becomes exclusively\noccupied in producing its own commodity, it must become dependent on\nthe rest for the other commodities it needs. And, simultaneously, a more\nperfectly-elaborated blood will result from a highly specialized group\nof nutritive organs, severally adapted to prepare its different\nelements; in the same way that the stream of commodities circulating\nthroughout a society, will be of superior quality in proportion to the\ngreater division of labour among the workers. Observe, also, that in\neither case the circulating mass of nutritive materials, besides coming\ngradually to consist of better ingredients, also grows more complex. An\nincrease in the number of the unlike organs which add to the blood their\nwaste matters, and demand from it the different materials they severally\nneed, implies a blood more heterogeneous in composition--an _a priori_\nconclusion which, according to Dr. Williams, is inductively confirmed by\nexamination of the blood throughout the various grades of the animal\nkingdom. And similarly, it is manifest that as fast as the division of\nlabour among the classes of a community becomes greater, there must be\nan increasing heterogeneity in the currents of merchandize flowing\nthroughout that community.\n\nThe circulating mass of nutritive materials in individual organisms and\nin social organisms, becoming at once better in the quality of its\ningredients and more heterogeneous in composition, as the type of\nstructure becomes higher, eventually has added to it in both cases\nanother element, which is not itself nutritive but facilitates the\nprocesses of nutrition. We refer, in the case of the individual\norganism, to the blood-discs; and in the case of the social organism, to\nmoney. This analogy has been observed by Liebig, who in his _Familiar\nLetters on Chemistry_ says:--\n\n     \"Silver and gold have to perform in the organism of the state, the\n     same function as the blood-corpuscles in the human organism. As\n     these round discs, without themselves taking an immediate share in\n     the nutritive process, are the medium, the essential condition of\n     the change of matter, of the production of the heat and of the\n     force by which the temperature of the body is kept up, and the\n     motions of the blood and all the juices are determined, so has gold\n     become the medium of all activity in the life of the state.\"\n\nAnd blood-corpuscles being like coin in their functions, and in the fact\nthat they are not consumed in nutrition, he further points out that the\nnumber of them which in a considerable interval flows through the great\ncentres, is enormous when compared with their absolute number; just as\nthe quantity of money which annually passes through the great mercantile\ncentres, is enormous when compared with the quantity of money in the\nkingdom. Nor is this all. Liebig has omitted the significant\ncircumstance that only at a certain stage of organization does this\nelement of the circulation make its appearance. Throughout extensive\ndivisions of the lower animals, the blood contains no corpuscles; and in\nsocieties of low civilization, there is no money.\n\nThus far we have considered the analogy between the blood in a living\nbody and the consumable and circulating commodities in the body-politic.\nLet us now compare the appliances by which they are respectively\ndistributed. We shall find in the developments of these appliances\nparallelisms not less remarkable than those above set forth. Already we\nhave shown that, as classes, wholesale and retail distributors discharge\nin a society the office which the vascular system discharges in an\nindividual creature; that they come into existence later than the other\ntwo great classes, as the vascular layer appears later than the mucous\nand serous layers; and that they occupy a like intermediate position.\nHere, however, it remains to be pointed out that a complete conception\nof the circulating system in a society, includes not only the active\nhuman agents who propel the currents of commodities, and regulate their\ndistribution, but includes, also, the channels of communication. It is\nthe formation and arrangement of these to which we now direct attention.\n\nGoing back once more to those lower animals in which there is found\nnothing but a partial diffusion, not of blood, but only of crude\nnutritive fluids, it is to be remarked that the channels through which\nthe diffusion takes place, are mere excavations through the\nhalf-organized substance of the body: they have no lining membranes, but\nare mere _lacunae_ traversing a rude tissue. Now countries in which\ncivilization is but commencing, display a like condition: there are no\nroads properly so called; but the wilderness of vegetal life covering\nthe earth's surface is pierced by tracks, through which the distribution\nof crude commodities takes place. And while, in both cases, the acts of\ndistribution occur only at long intervals (the currents, after a pause,\nnow setting towards a general centre and now away from it), the transfer\nis in both cases slow and difficult. But among other accompaniments of\nprogress, common to animals and societies, comes the formation of more\ndefinite and complete channels of communication. Blood-vessels acquire\ndistinct walls; roads are fenced and gravelled. This advance is first\nseen in those roads or vessels that are nearest to the chief centres of\ndistribution; while the peripheral roads and peripheral vessels long\ncontinue in their primitive states. At a yet later stage of development,\nwhere comparative finish of structure is found throughout the system as\nwell as near the chief centres, there remains in both cases the\ndifference that the main channels are comparatively broad and straight,\nwhile the subordinate ones are narrow and tortuous in proportion to\ntheir remoteness. Lastly, it is to be remarked that there ultimately\narise in the higher social organisms, as in the higher individual\norganisms, main channels of distribution still more distinguished by\ntheir perfect structures, their comparative straightness, and the\nabsence of those small branches which the minor channels perpetually\ngive off. And in railways we also see, for the first time in the social\norganism, a system of double channels conveying currents in opposite\ndirections, as do the arteries and veins of a well-developed animal.\n\nThese parallelisms in the evolutions and structures of the circulating\nsystems, introduce us to others in the kinds and rates of the movements\ngoing on through them. Through the lowest societies, as through the\nlowest creatures, the distribution of crude nutriment is by slow\ngurgitations and regurgitations. In creatures that have rude vascular\nsystems, just as in societies that are beginning to have roads, there is\nno regular circulation along definite courses; but, instead, periodical\nchanges of the currents--now towards this point and now towards that.\nThrough each part of an inferior mollusk's body, the blood flows for a\nwhile in one direction, then stops and flows in the opposite direction;\njust as through a rudely-organized society, the distribution of\nmerchandize is slowly carried on by great fairs, occurring in different\nlocalities, to and from which the currents periodically set. Only\nanimals of tolerably complete organizations, like advanced communities,\nare permeated by constant currents that are definitely directed. In\nliving bodies, the local and variable currents disappear when there grow\nup great centres of circulation, generating more powerful currents by a\nrhythm which ends in a quick, regular pulsation. And when in social\nbodies there arise great centres of commercial activity, producing and\nexchanging large quantities of commodities, the rapid and continuous\nstreams drawn in and emitted by these centres subdue all minor and local\ncirculations: the slow rhythm of fairs merges into the faster one of\nweekly markets, and in the chief centres of distribution, weekly markets\nmerge into daily markets; while in place of the languid transfer from\nplace to place, taking place at first weekly, then twice or thrice a\nweek, we by-and-by get daily transfer, and finally transfer many times a\nday--the original sluggish, irregular rhythm, becomes a rapid, equable\npulse. Mark, too, that in both cases the increased activity, like the\ngreater perfection of structure, is much less conspicuous at the\nperiphery of the vascular system. On main lines of railway, we have,\nperhaps, a score trains in each direction daily, going at from thirty to\nfifty miles an hour; as, through the great arteries, the blood moves\nrapidly in successive gushes. Along high roads, there go vehicles\nconveying men and commodities with much less, though still considerable,\nspeed, and with a much less decided rhythm; as, in the smaller arteries,\nthe speed of the blood is greatly diminished and the pulse less\nconspicuous. In parish-roads, narrower, less complete, and more\ntortuous, the rate of movement is further decreased and the rhythm\nscarcely traceable; as in the ultimate arteries. In those still more\nimperfect by-roads which lead from these parish-roads to scattered\nfarmhouses and cottages, the motion is yet slower and very irregular;\njust as we find it in the capillaries. While along the field-roads,\nwhich, in their unformed, unfenced state, are typical of _lacunae_, the\nmovement is the slowest, the most irregular, and the most infrequent; as\nit is, not only in the primitive _lacunae_ of animals and societies, but\nas it is also in those _lacunae_ in which the vascular system ends among\nextensive families of inferior creatures.\n\nThus, then, we find between the distributing systems of living bodies\nand the distributing systems of bodies-politic, wonderfully close\nparallelisms. In the lowest forms of individual and social organisms,\nthere exist neither prepared nutritive matters nor distributing\nappliances; and in both, these, arising as necessary accompaniments of\nthe differentiation of parts, approach perfection as this\ndifferentiation approaches completeness. In animals, as in societies,\nthe distributing agencies begin to show themselves at the same relative\nperiods, and in the same relative positions. In the one, as in the\nother, the nutritive materials circulated are at first crude and simple,\ngradually become better elaborated and more heterogeneous, and have\neventually added to them a new element facilitating the nutritive\nprocesses. The channels of communication pass through similar phases of\ndevelopment, which bring them to analogous forms. And the directions,\nrhythms, and rates of circulation, progress by like steps to like final\nconditions.\n\n       *       *       *       *       *\n\nWe come at length to the nervous system. Having noticed the primary\ndifferentiation of societies into the governing and governed classes,\nand observed its analogy to the differentiation of the two primary\ntissues which respectively develop into organs of external action and\norgans of alimentation; having noticed some of the leading analogies\nbetween the development of industrial arrangements and that of the\nalimentary apparatus; and having, above, more fully traced the analogies\nbetween the distributing systems, social and individual; we have now to\ncompare the appliances by which a society, as a whole, is regulated,\nwith those by which the movements of an individual creature are\nregulated. We shall find here parallelisms equally striking with those\nalready detailed.\n\nThe class out of which governmental organization originates, is, as we\nhave said, analogous in its relations to the ectoderm of the lowest\nanimals and of embryonic forms. And as this primitive membrane, out of\nwhich the nervo-muscular system is evolved, must, even in the first\nstage of its differentiation, be slightly distinguished from the rest by\nthat greater impressibility and contractility characterizing the organs\nto which it gives rise; so, in that superior class which is eventually\ntransformed into the directo-executive system of a society (its\nlegislative and defensive appliances), does there exist in the\nbeginning, a larger endowment of the capacities required for these\nhigher social functions. Always, in rude assemblages of men, the\nstrongest, most courageous, and most sagacious, become rulers and\nleaders; and, in a tribe of some standing, this results in the\nestablishment of a dominant class, characterized on the average by those\nmental and bodily qualities which fit them for deliberation and\nvigorous combined action. Thus that greater impressibility and\ncontractility, which in the rudest animal types characterize the units\nof the ectoderm, characterize also the units of the primitive social\nstratum which controls and fights; since impressibility and\ncontractility are the respective roots of intelligence and strength.\n\nAgain, in the unmodified ectoderm, as we see it in the _Hydra_, the\nunits are all endowed both with impressibility and contractility; but as\nwe ascend to higher types of organization, the ectoderm differentiates\ninto classes of units which divide those two functions between them:\nsome, becoming exclusively impressible, cease to be contractile; while\nsome, becoming exclusively contractile, cease to be impressible.\nSimilarly with societies. In an aboriginal tribe, the directive and\nexecutive functions are diffused in a mingled form throughout the whole\ngoverning class. Each minor chief commands those under him, and, if need\nbe, himself coerces them into obedience. The council of chiefs itself\ncarries out on the battle-field its own decisions. The head chief not\nonly makes laws, but administers justice with his own hands. In larger\nand more settled communities, however, the directive and executive\nagencies begin to grow distinct from each other. As fast as his duties\naccumulate, the head chief or king confines himself more and more to\ndirecting public affairs, and leaves the execution of his will to\nothers: he deputes others to enforce submission, to inflict punishments,\nor to carry out minor acts of offence and defence; and only on occasions\nwhen, perhaps, the safety of the society and his own supremacy are at\nstake, does he begin to act as well as direct. As this differentiation\nestablishes itself, the characteristics of the ruler begin to change. No\nlonger, as in an aboriginal tribe, the strongest and most daring man,\nthe tendency is for him to become the man of greatest cunning,\nforesight, and skill in the management of others; for in societies that\nhave advanced beyond the first stage, it is chiefly such qualities\nthat insure success in gaining supreme power, and holding it against\ninternal and external enemies. Thus that member of the governing class\nwho comes to be the chief directing agent, and so plays the same part\nthat a rudimentary nervous centre does in an unfolding organism, is\nusually one endowed with some superiorities of nervous organization.\n\nIn those larger and more complex communities possessing, perhaps, a\nseparate military class, a priesthood, and dispersed masses of\npopulation requiring local control, there grow up subordinate governing\nagents; who, as their duties accumulate, severally become more directive\nand less executive in their characters. And when, as commonly happens,\nthe king begins to collect round himself advisers who aid him by\ncommunicating information, preparing subjects for his judgment, and\nissuing his orders; we may say that the form of organization is\ncomparable to one very general among inferior types of animals, in which\nthere exists a chief ganglion with a few dispersed minor ganglia under\nits control.\n\nThe analogies between the evolution of governmental structures in\nsocieties, and the evolution of governmental structures in living\nbodies, are, however, more strikingly displayed during the formation of\nnations by coalescence of tribes--a process already shown to be, in\nseveral respects, parallel to the development of creatures that\nprimarily consist of many like segments. Among other points of community\nbetween the successive rings which make up the body in the lower\n_Annulosa_, is the possession of similar pairs of ganglia. These pairs\nof ganglia, though connected by nerves, are very incompletely dependent\non any general controlling power. Hence it results that when the body is\ncut in two, the hinder part continues to move forward under the\npropulsion of its numerous legs; and that when the chain of ganglia has\nbeen divided without severing the body, the hind limbs may be seen\ntrying to propel the body in one direction while the fore limbs are\ntrying to propel it in another. But in the higher _Annulosa_, called\n_Articulata_, sundry of the anterior pairs of ganglia, besides growing\nlarger, unite in one mass; and this great cephalic ganglion having\nbecome the co-ordinator of all the creature's movements, there no longer\nexists much local independence. Now may we not in the growth of a\nconsolidated kingdom out of petty sovereignties or baronies, observe\nanalogous changes? Like the chiefs and primitive rulers above described,\nfeudal lords, exercising supreme power over their respective groups of\nretainers, discharge functions analogous to those of rudimentary nervous\ncentres. Among these local governing centres there is, in early feudal\ntimes, very little subordination. They are in frequent antagonism; they\nare individually restrained chiefly by the influence of parties in their\nown class; and they are but irregularly subject to that most powerful\nmember of their order who has gained the position of head-suzerain or\nking. As the growth and organization of the society progresses, these\nlocal directive centres fall more and more under the control of a chief\ndirective centre. Closer commercial union between the several segments\nis accompanied by closer governmental union; and these minor rulers end\nin being little more than agents who administer, in their several\nlocalities, the laws made by the supreme ruler: just as the local\nganglia above described, eventually become agents which enforce, in\ntheir respective segments, the orders of the cephalic ganglion. The\nparallelism holds still further. We remarked above, when speaking of the\nrise of aboriginal kings, that in proportion as their territories\nincrease, they are obliged not only to perform their executive functions\nby deputy, but also to gather round themselves advisers to aid in their\ndirective functions; and that thus, in place of a solitary governing\nunit, there grows up a group of governing units, comparable to a\nganglion consisting of many cells. Let us here add that the advisers and\nchief officers who thus form the rudiment of a ministry, tend from the\nbeginning to exercise some control over the ruler. By the information\nthey give and the opinions they express, they sway his judgment and\naffect his commands. To this extent he is made a channel through which\nare communicated the directions originating with them; and in course of\ntime, when the advice of ministers becomes the acknowledged source of\nhis actions, the king assumes the character of an automatic centre,\nreflecting the impressions made on him from without.\n\nBeyond this complication of governmental structure many societies do not\nprogress; but in some, a further development takes place. Our own case\nbest illustrates this further development and its further analogies. To\nkings and their ministries have been added, in England, other great\ndirective centres, exercising a control which, at first small, has been\ngradually becoming predominant: as with the great governing ganglia\nwhich especially distinguish the highest classes of living beings.\nStrange as the assertion will be thought, our Houses of Parliament\ndischarge, in the social economy, functions which are in sundry respects\ncomparable to those discharged by the cerebral masses in a vertebrate\nanimal. As it is in the nature of a single ganglion to be affected only\nby special stimuli from particular parts of the body; so it is in the\nnature of a single ruler to be swayed in his acts by exclusive personal\nor class interests. As it is in the nature of a cluster of ganglia,\nconnected with the primary one, to convey to it a greater variety of\ninfluences from more numerous organs, and thus to make its acts conform\nto more numerous requirements; so it is in the nature of the subsidiary\ncontrolling powers surrounding a king to adapt his rule to a greater\nnumber of public exigencies. And as it is in the nature of those great\nand latest-developed ganglia which distinguish the higher animals, to\ninterpret and combine the multiplied and varied impressions conveyed to\nthem from all parts of the system, and to regulate the actions in such\nway as duly to regard them all; so it is in the nature of those great\nand latest-developed legislative bodies which distinguish the most\nadvanced societies, to interpret and combine the wishes of all classes\nand localities, and to make laws in harmony with the general wants. We\nmay describe the office of the brain as that of _averaging_ the\ninterests of life, physical, intellectual, moral; and a good brain is\none in which the desires answering to these respective interests are so\nbalanced, that the conduct they jointly dictate, sacrifices none of\nthem. Similarly, we may describe the office of a Parliament as that of\n_averaging_ the interests of the various classes in a community; and a\ngood Parliament is one in which the parties answering to these\nrespective interests are so balanced, that their united legislation\nallows to each class as much as consists with the claims of the rest.\nBesides being comparable in their duties, these great directive centres,\nsocial and individual, are comparable in the processes by which their\nduties are discharged. The cerebrum is not occupied with direct\nimpressions from without but with the ideas of such impressions. Instead\nof the actual sensations produced in the body, and directly appreciated\nby the sensory ganglia, or primitive nervous centres, the cerebrum\nreceives only the representations of these sensations; and its\nconsciousness is called _representative_ consciousness, to distinguish\nit from the original or _presentative_ consciousness. Is it not\nsignificant that we have hit on the same word to distinguish the\nfunction of our House of Commons? We call it a _representative_ body,\nbecause the interests with which it deals are not directly presented to\nit, but represented to it by its various members; and a debate is a\nconflict of representations of the results likely to follow from a\nproposed course--a description which applies with equal truth to a\ndebate in the individual consciousness. In both cases, too, these great\ngoverning masses take no part in the executive functions. As, after a\nconflict in the cerebrum, those desires which finally predominate act\non the subjacent ganglia, and through their instrumentality determine\nthe bodily actions; so the parties which, after a parliamentary\nstruggle, gain the victory, do not themselves carry out their wishes,\nbut get them carried out by the executive divisions of the Government.\nThe fulfilment of all legislative decisions still devolves on the\noriginal directive centres: the impulse passing from the Parliament to\nthe Ministers and from the Ministers to the King, in whose name\neverything is done; just as those smaller, first-developed ganglia,\nwhich in the lowest vertebrata are the chief controlling agents, are\nstill, in the brains of the higher vertebrata, the agents through which\nthe dictates of the cerebrum are worked out. Moreover, in both cases\nthese original centres become increasingly automatic. In the developed\nvertebrate animal, they have little function beyond that of conveying\nimpressions to, and executing the determinations of, the larger centres.\nIn our highly organized government, the monarch has long been lapsing\ninto a passive agent of Parliament; and now, ministries are rapidly\nfalling into the same position. Nay, between the two cases there is a\nparallelism even in respect of the exceptions to this automatic action.\nFor in the individual creature it happens that under circumstances of\nsudden alarm, as from a loud sound close at hand, an unexpected object\nstarting up in front, or a slip from insecure footing, the danger is\nguarded against by some quick involuntary jump, or adjustment of the\nlimbs, which occurs before there is time to consider the impending evil\nand take deliberate measures to avoid it: the rationale of which is that\nthese violent impressions produced on the senses, are reflected from the\nsensory ganglia to the spinal cord and muscles, without, as in ordinary\ncases, first passing through the cerebrum. In like manner on national\nemergencies calling for prompt action, the King and Ministry, not having\ntime to lay the matter before the great deliberative bodies, themselves\nissue commands for the requisite movements or precautions: the\nprimitive, and now almost automatic, directive centres, resume for a\nmoment their original uncontrolled power. And then, strangest of all,\nobserve that in either case there is an after-process of approval or\ndisapproval. The individual on recovering from his automatic start, at\nonce contemplates the cause of his fright; and, according to the case,\nconcludes that it was well he moved as he did, or condemns himself for\nhis groundless alarm. In like manner, the deliberative powers of the\nState discuss, as soon as may be, the unauthorized acts of the executive\npowers; and, deciding that the reasons were or were not sufficient,\ngrant or withhold a bill of indemnity.[28]\n\nThus far in comparing the governmental organization of the body-politic\nwith that of an individual body, we have considered only the respective\nco-ordinating centres. We have yet to consider the channels through\nwhich these co-ordinating centres receive information and convey\ncommands. In the simplest societies, as in the simplest organisms, there\nis no \"internuncial apparatus,\" as Hunter styled the nervous system.\nConsequently, impressions can be but slowly propagated from unit to unit\nthroughout the whole mass. The same progress, however, which, in\nanimal-organization, shows itself in the establishment of ganglia or\ndirective centres, shows itself also in the establishment of\nnerve-threads, through which the ganglia receive and convey impressions\nand so control remote organs. And in societies the like eventually\ntakes place. After a long period during which the directive centres\ncommunicate with various parts of the society through other means, there\nat last comes into existence an \"internuncial apparatus,\" analogous to\nthat found in individual bodies. The comparison of telegraph-wires to\nnerves is familiar to all. It applies, however, to an extent not\ncommonly supposed. Thus, throughout the vertebrate sub-kingdom, the\ngreat nerve-bundles diverge from the vertebrate axis side by side with\nthe great arteries; and similarly, our groups of telegraph-wires are\ncarried along the sides of our railways. The most striking parallelism,\nhowever, remains. Into each great bundle of nerves, as it leaves the\naxis of the body along with an artery, there enters a branch of the\nsympathetic nerve; which branch, accompanying the artery throughout its\nramifications, has the function of regulating its diameter and otherwise\ncontrolling the flow of blood through it according to local\nrequirements. Analogously, in the group of telegraph-wires running\nalongside each railway, there is a wire for the purpose of regulating\nthe traffic--for retarding or expediting the flow of passengers and\ncommodities, as the local conditions demand. Probably, when our now\nrudimentary telegraph-system is fully developed, other analogies will be\ntraceable.\n\nSuch, then, is a general outline of the evidence which justifies the\ncomparison of societies to living organisms. That they gradually\nincrease in mass; that they become little by little more complex; that\nat the same time their parts grow more mutually dependent; and that they\ncontinue to live and grow as wholes, while successive generations of\ntheir units appear and disappear; are broad peculiarities which\nbodies-politic display in common with all living bodies; and in which\nthey and living bodies differ from everything else. And on carrying out\nthe comparison in detail, we find that these major analogies involve\nmany minor analogies, far closer than might have been expected. Others\nmight be added. We had hoped to say something respecting the different\ntypes of social organization, and something also on social\nmetamorphoses; but we have reached our assigned limits.\n\nFOOTNOTE:\n\n[Footnote 28: It may be well to warn the reader against an error fallen\ninto by one who criticised this essay on its first publication--the\nerror of supposing that the analogy here intended to be drawn, is a\nspecific analogy between the organization of society in England, and the\nhuman organization. As said at the outset, no such specific analogy\nexists. The above parallel is one between the most-developed systems of\ngovernmental organization, individual and social; and the vertebrate\ntype is instanced merely as exhibiting this most-developed system. If\nany specific comparison were made, which it cannot rationally be, it\nwould be made with some much lower vertebrate form than the human.]\n\n\n\n\nTHE ORIGIN OF ANIMAL WORSHIP.\n\n    [_First published in_ The Fortnightly Review _for May,_ 1870.]\n\n\nMr. McLennan's recent essays on the Worship of Animals and Plants have\ndone much to elucidate a very obscure subject. By pursuing in this case,\nas before in another case, the truly scientific method of comparing the\nphenomena presented by existing uncivilized races with those which the\ntraditions of civilized races present, he has rendered both of them more\ncomprehensible than they were before.\n\nIt seems to me, however, that Mr. McLennan gives but an indefinite\nanswer to the essential question--How did the worship of animals and\nplants arise? Indeed, in his concluding paper, he expressly leaves this\nproblem unsolved; saying that his \"is not an hypothesis explanatory of\nthe origin of _Totemism_, be it remembered, but an hypothesis\nexplanatory of the animal and plant worship of the ancient nations.\" So\nthat we have still to ask--Why have savage tribes so generally taken\nanimals and plants and other things as totems? What can have induced\nthis tribe to ascribe special sacredness to one creature, and that tribe\nto another? And if to these questions the reply is, that each tribe\nconsiders itself to be descended from the object of its reverence, then\nthere presses for answer the further question--How came so strange a\nnotion into existence? If this notion occurred in one case only, we\nmight set it down to some whim of thought or some illusive occurrence.\nBut appealing, as it does, with multitudinous variations among so many\nuncivilized races in different parts of the world, and having left\nnumerous marks in the superstitions of extinct civilized races, we\ncannot assume any special or exceptional cause. Moreover, the general\ncause, whatever it may be, must be such as does not negative an\naboriginal intelligence like in nature to our own. After studying the\ngrotesque beliefs of savages, we are apt to suppose that their reason is\nnot as our reason. But this supposition is inadmissible. Given the\namount of knowledge which primitive men possess, and given the imperfect\nverbal symbols used by them in speech and thought, and the conclusions\nthey habitually reach will be those that are _relatively_ the most\nrational. This must be our postulate; and, setting out with this\npostulate, we have to ask how primitive men came so generally, if not\nuniversally, to believe themselves the progeny of animals or plants or\ninanimate bodies. There is, I believe, a satisfactory answer.\n\n       *       *       *       *       *\n\nThe proposition with which Mr. McLennan sets out, that totem-worship\npreceded the worship of anthropomorphic gods, is one to which I can\nyield but a qualified assent. It is true in a sense, but not wholly\ntrue. If the words \"gods\" and \"worship\" carry with them their ordinary\ndefinite meanings, the statement is true; but if their meanings are\nwidened so as to comprehend those earliest vague notions out of which\nthe definite ideas of gods and worship are evolved, I think it is not\ntrue. The rudimentary form of all religion is the propitiation of dead\nancestors, who are supposed to be still existing, and to be capable of\nworking good or evil to their descendants. As a preparation for dealing\nhereafter with the principles of sociology, I have, for some years past,\ndirected much attention to the modes of thought current in the simpler\nhuman societies; and evidence of many kinds, furnished by all\nvarieties of uncivilized men, has forced on me a conclusion harmonizing\nwith that lately expressed in this Review by Prof. Huxley--namely, that\nthe savage, conceiving a corpse to be deserted by the active personality\nwho dwelt in it, conceives this active personality to be still existing,\nand that his feelings and ideas concerning it form the basis of his\nsuperstitions. Everywhere we find expressed Or implied the belief that\neach person is double; and that when he dies, his other self, whether\nremaining near at hand or gone far away, may return, and continues\ncapable of injuring his enemies and aiding his friends.[29]\n\nBut how out of the desire to propitiate this second personality of a\ndeceased man (the words \"ghost\" and \"spirit\" are somewhat misleading,\nsince the savage believes that the second personality reappears in a\nform equally tangible with the first), does there grow up the worship of\nanimals, plants, and inanimate objects? Very simply. Savages habitually\ndistinguish individuals by names that are either directly suggestive of\nsome personal trait or fact of personal history, or else express an\nobserved community of character with some well-known object. Such a\ngenesis of individual names, before surnames have arisen, is inevitable;\nand how easily it arises we shall see on remembering that it still goes\non in its original form, even when no longer needful. I do not refer\nonly to the significant fact that in some parts of England, as in the\nnail-making districts, nicknames are general, and surnames little\nrecognized; but I refer to a common usage among both children and\nadults. The rude man is apt to be known as \"a bear;\" a sly fellow, as\n\"an old fox;\" a hypocrite, as \"the crocodile.\" Names of plants, too, are\nused; as when the red-haired boy is called \"carrots\" by his\nschool-fellows. Nor do we lack nicknames derived from inorganic objects\nand agents: instance that given by Mr. Carlyle to the elder\nSterling--\"Captain Whirlwind.\" Now, in the earliest savage state, this\nmetaphorical naming will in most cases commence afresh in each\ngeneration--must do so, indeed, until surnames of some kind have been\nestablished. I say in most cases, because there will occur exceptions in\nthe cases of men who have distinguished themselves. If \"the Wolf,\"\nproving famous in fight, becomes a terror to neighbouring tribes, and a\ndominant man in his own, his sons, proud of their parentage, will not\nlet fall the fact that they descended from \"the Wolf\"; nor will this\nfact be forgotten by the rest of the tribe who hold \"the Wolf\" in awe,\nand see reason to dread his sons. In proportion to the power and\ncelebrity of \"the Wolf\" will this pride and this fear conspire to\nmaintain among his grandchildren and great-grandchildren, as well as\namong those over whom they dominate, the remembrance of the fact that\ntheir ancestor was \"the Wolf\". And if, as will occasionally happen, this\ndominant family becomes the root of a new tribe, the members of this\ntribe will become known to themselves and others as \"the Wolves\".\n\nWe need not rest satisfied with the inference that this inheritance of\nnicknames _will_ take place. There is proof that it _does_ take place.\nAs nicknaming after animals, plants, and other objects, still goes on\namong ourselves, so among ourselves does there go on the descent of\nnicknames. An instance has come under my own notice on an estate in the\nWest Highlands, belonging to some friends with whom I frequently have\nthe pleasure of spending a few weeks in the autumn. \"Take a young\nCroshek,\" has more than once been the reply of my host to the inquiry,\nwho should go with me, when I was setting out salmon-fishing. The elder\nCroshek I knew well; and supposed that this name, borne by him and by\nall belonging to him, was the family surname. Years passed before I\nlearned that the real surname was Cameron; that the father was called\nCroshek, after the name of his cottage, to distinguish him from other\nCamerons employed about the premises; and that his children had come to\nbe similarly distinguished. Though here, as very generally in Scotland,\nthe nickname was derived from the place of residence, yet had it been\nderived from an animal, the process would have been the same:\ninheritance of it would have occurred just as naturally. Not even for\nthis small link in the argument, however, need we depend on inference.\nThere is fact to bear us out. Mr. Bates, in his _Naturalist on the River\nAmazons_ (2d ed., p. 376), describing three half-castes who accompanied\nhim on a hunting trip, says--\"Two of them were brothers, namely, Joao\n(John) and Zephyrino Jabuti: Jabuti, or tortoise, being a nickname which\ntheir father had earned for his slow gait, and which, as is usual in\nthis country, had descended as the surname of the family.\" Let me add\nthe statement made by Mr. Wallace respecting this same region, that \"one\nof the tribes on the river Isanna is called 'Jurupari' (Devils). Another\nis called 'Ducks;' a third, 'Stars;' a fourth, 'Mandiocca.'\" Putting\nthese two statements together, can there be any doubt about the genesis\nof these tribal names? Let \"the Tortoise\" become sufficiently\ndistinguished (not necessarily by superiority--great inferiority may\noccasionally suffice) and the tradition of descent from him, preserved\nby his descendants themselves if he was superior, and by their\ncontemptuous neighbours if he was inferior, may become a tribal\nname.[30]\n\n\"But this,\" it will be said, \"does not amount to an explanation of\nanimal-worship.\" True: a third factor remains to be specified. Given a\nbelief in the still-existing other self of the deceased ancestor, who\nmust be propitiated; given this survival of his metaphorical name among\nhis grandchildren, great-grandchildren, etc.; and the further requisite\nis that the distinction between metaphor and reality shall be forgotten.\nLet tradition fail to keep clearly in view the fact that the ancestor\nwas a man called \"the Wolf\"--let him be habitually spoken of as \"the\nWolf\", just as when alive; and the natural mistake of taking the name\nliterally will bring with it, firstly, a belief in descent from an\nactual wolf, and, secondly, a treatment of the wolf in a manner likely\nto propitiate him--a manner appropriate to one who may be the other self\nof the dead ancestor, or one of the kindred, and therefore a friend.\n\nThat a misunderstanding of this kind is likely to grow up, becomes\nobvious when we bear in mind the great indefiniteness of\nprimitive language. As Prof. Max Mueller says, respecting certain\nmisinterpretations of an opposite kind: \"These metaphors ... would\nbecome mere names handed down in the conversation of a family,\nunderstood perhaps by the grandfather, familiar to the father, but\nstrange to the son, and misunderstood by the grandson.\" We have ample\nreason, then, for supposing such misinterpretations. Nay, we may go\nfurther. We are justified in saying that they are certain to occur. For\nundeveloped languages contain no words capable of indicating the\ndistinction to be kept in view. In the tongues of existing inferior\nraces, only concrete objects and acts are expressible. The Australians\nhave a name for each kind of tree, but no name for tree irrespective of\nkind. And though some witnesses allege that their vocabulary is not\nabsolutely destitute of generic names, its extreme poverty in such is\nunquestionable. Similarly with the Tasmanians. Dr. Milligan says they\n\"had acquired very limited powers of abstraction or generalization. They\npossessed no words representing abstract ideas; for each variety of\ngum-tree and wattle-tree, etc., etc., they had a name, but they had no\nequivalent for the expression, 'a tree;' neither could they express\nabstract qualities, such as hard, soft, warm, cold, long, short, round,\netc.; for 'hard,' they would say 'like a stone;' for 'tall,' they would\nsay 'long legs,' etc.; and for 'round,' they said 'like a ball,' 'like\nthe moon,' and so on, usually suiting the action to the word, and\nconfirming, by some sign, the meaning to be understood.\"[31] Now, even\nmaking allowance for over-statement here (which seems needful, since the\nword \"long,\" said to be inexpressible in the abstract, subsequently\noccurs as qualifying a concrete in the expression, \"long legs\"), it is\nmanifest that so imperfect a language must fail to convey the idea of a\nname, as something separate from a thing; and that still less can it be\ncapable of indicating the act of naming. Familiar use of such\npartially-abstract words as are applicable to all objects of a class, is\nneedful before there can be reached the conception of a name--a word\nsymbolizing the symbolic character of other words; and the conception of\na name, with its answering abstract term, must be long current before\nthe verb to name can arise. Hence, men with speech so rude, cannot\ntransmit the tradition of an ancestor named \"the Wolf\", as distinguished\nfrom the actual wolf. The children and grandchildren who saw him will\nnot be led into error; but in later generations, descent from \"the Wolf\"\nwill inevitably come to mean descent from the animal known by that name.\nAnd the ideas and sentiments which, as above shown, naturally grow up\nround the belief that the dead parents and grandparents are still alive,\nand ready, if propitiated, to befriend their descendants, will be\nextended to the wolf species.\n\nBefore passing to other developments of this general view, let me point\nout how not simply animal-worship is thus accounted for, but also the\nconception, so variously illustrated in ancient legends, that animals\nare capable of displaying human powers of speech and thought and action.\nMythologies are full of stories of beasts and birds and fishes that have\nplayed intelligent parts in human affairs--creatures that have\nbefriended particular persons by giving them information, by guiding\nthem, by yielding them help; or else that have deceived them, verbally\nor otherwise. Evidently all these traditions, as well as those about\nabductions of women by animals and fostering of children by them, fall\nnaturally into their places as results of the habitual misinterpretation\nI have described.\n\n       *       *       *       *       *\n\nThe probability of the hypothesis will appear still greater when we\nobserve how readily it applies to the worship of other orders of\nobjects. Belief in actual descent from an animal, strange as we may\nthink it, is one by no means incongruous with the unanalyzed experiences\nof the savage; for there come under his notice many metamorphoses,\nvegetal and animal, which are apparently of like character. But how\ncould he possibly arrive at so grotesque a conception as that the\nprogenitor of his tribe was the sun, or the moon, or a particular star?\nNo observation of surrounding phenomena affords the slightest suggestion\nof any such possibility. But by the inheritance of nicknames that are\neventually mistaken for the names of the objects from which they were\nderived, the belief readily arises--is sure to arise. That the names of\nheavenly bodies will furnish metaphorical names to the uncivilized, is\nmanifest. Do we not ourselves call a distinguished singer or actor a\nstar? And have we not in poems numerous comparisons of men and women to\nthe sun and moon; as in _Love's Labour's Lost_, where the princess is\ncalled \"a gracious moon,\" and as in _Henry VII._, where we read--\"Those\nsuns of glory, those two lights of men?\" Clearly, primitive peoples will\nbe not unlikely thus to speak of the chief hero of a successful battle.\nWhen we remember how the arrival of a triumphant warrior must affect the\nfeelings of his tribe, dissipating clouds of anxiety and brightening all\nfaces with joy, we shall see that the comparison of him to the sun is\nquite natural; and in early speech this comparison can be made only by\ncalling him the sun. As before, then, it will happen that, through a\nconfounding of the metaphorical name with the actual name, his progeny,\nafter a few generations, will be regarded by themselves and others as\ndescendants of the sun. And, as a consequence, partly of actual\ninheritance of the ancestral character, and partly of maintenance of the\ntraditions respecting the ancestor's achievements, it will also\nnaturally happen that the solar race will be considered a superior race,\nas we find it habitually is.\n\nThe origin of other totems, equally strange, if not even stranger, is\nsimilarly accounted for, though otherwise unaccountable. One of the\nNew-Zealand chiefs claimed as his progenitor the neighbouring great\nmountain, Tongariro. This seemingly-whimsical belief becomes\nintelligible when we observe how easily it may have arisen from a\nnickname. Do we not ourselves sometimes speak figuratively of a tall,\nfat man as a mountain of flesh? And, among a people prone to speak in\nstill more concrete terms, would it not happen that a chief, remarkable\nfor his great bulk, would be nicknamed after the highest mountain within\nsight, because he towered above other men as this did above surrounding\nhills? Such an occurrence is not simply possible, but probable. And, if\nso, the confusion of metaphor with fact would originate this surprising\ngenealogy. A notion perhaps yet more grotesque, thus receives a\nsatisfactory interpretation. What could have put it into the imagination\nof any one that he was descended from the dawn? Given the extremest\ncredulity, joined with the wildest fancy, it would still seem requisite\nthat the ancestor should be conceived as an entity; and the dawn is\nentirely without that definiteness and comparative constancy which enter\ninto the conception of an entity. But when we remember that \"the Dawn\"\nis a natural complimentary name for a beautiful girl opening into\nwomanhood, the genesis of the idea becomes, on the above hypothesis,\nquite obvious.[32]\n\n       *       *       *       *       *\n\nAnother indirect verification is that we thus get a clear conception of\nFetichism in general. Under the fetichistic mode of thought, surrounding\nobjects and agents are regarded as having powers more or less definitely\npersonal in their natures; and the current interpretation is, that human\nintelligence, in its early stages, is obliged to conceive of their\npowers under this form. I have myself hitherto accepted this\ninterpretation; though always with a sense of dissatisfaction. This\ndissatisfaction was, I think, well grounded. The theory is scarcely a\ntheory properly so-called; but rather, a restatement in other words.\nUncivilized men _do_ habitually form anthropomorphic conceptions of\nsurrounding things; and this observed general fact is transformed into\nthe theory that at first they _must_ so conceive them--a theory for\nwhich the psychological justification attempted, seems to me inadequate.\nFrom our present stand-point, it becomes manifest that Fetichism is not\nprimary but secondary. What has been said above almost of itself shows\nthis. Let us, however, follow out the steps of its genesis. Respecting\nthe Tasmanians, Dr. Milligan says:--\"The names of men and women were\ntaken from natural objects and occurrences around, as, for instance, a\nkangaroo, a gum tree, snow, hail, thunder, the wind,\" flowers in\nblossom, etc. Surrounding objects, then, giving origin to names of\npersons, and being, in the way shown, eventually mistaken for the actual\nprogenitors of those who descend from persons nicknamed after them, it\nresults that these surrounding objects come to be regarded as in some\nmanner possessed of personalities like the human. He whose family\ntradition is that his ancestor was \"the Crab,\" will conceive the crab as\nhaving a disguised inner power like his own; an alleged descent from\n\"the Palm-tree\" will entail belief in some kind of consciousness\ndwelling in the palm-tree. Hence, in proportion as the animals, plants,\nand inanimate objects or agents that originate names of persons, become\nnumerous (which they will do in proportion as a tribe becomes large and\nthe number of persons to be distinguished from one another increases),\nmultitudinous things around will acquire imaginary personalities. And so\nit will happen that, as Mr. McLennan says of the Feejeeans, \"Vegetables\nand stones, nay, even tools and weapons, pots and canoes, have souls\nthat are immortal, and that, like the souls of men, pass on at last to\nMbulu, the abode of departed spirits.\" Setting out, then, with a belief\nin the still-living other self of the dead ancestor, the alleged general\ncause of misapprehension affords us an intelligible origin of the\nfetichistic conception; and we are enabled to see how it tends to become\na general, if not a universal, conception.\n\n       *       *       *       *       *\n\nOther apparently inexplicable phenomena are at the same time divested of\ntheir strangeness. I refer to the beliefs in, and worship of, compound\nmonsters--impossible hybrid animals, and forms that are half human, half\nbrutal. The theory of a primordial Fetichism, supposing it otherwise\nadequate, yields no feasible solutions of these. Grant the alleged\noriginal tendency to think of all natural agencies as in some way\npersonal. Grant, too, that hence may arise a worship of animals, plants,\nand even inanimate bodies. Still the obvious implication is that the\nworship so derived will be limited to things that are, or have been,\nperceived. Why should this mode of thought lead the savage to imagine a\ncombination of bird and mammal; and not only to imagine it, but to\nworship it as a god? If even we admit that some illusion may have\nsuggested the belief in a creature half man, half fish, we cannot thus\nexplain the prevalence among Eastern races of idols representing\nbird-headed men, and men having their legs replaced by the legs of a\ncock, and men with the heads of elephants.\n\nCarrying with us the inferences above drawn, however, it is a corollary\nthat ideas and practices of these kinds will arise. When tradition\npreserves both lines of ancestry--when a chief, nicknamed \"the Wolf\",\ncarries away from an adjacent tribe a wife who is remembered either\nunder the animal name of her tribe, or as a woman; it will happen that\nif a son distinguishes himself, the remembrance of him among his\ndescendants will be that he was born of a wolf and some other animal, or\nof a wolf and a woman. Misinterpretation, arising in the way described\nfrom defects of language, will entail belief in a creature uniting the\nattributes of the two; and if the tribe grows into a society,\nrepresentations of such a creature will become objects of worship. One\nof the cases cited by Mr. McLennan may here be repeated in illustration.\n\"The story of the origin of the Dikokamenni Kirgheez,\" they say, \"from a\nred greyhound and a certain queen and her forty handmaidens, is of\nancient date.\" Now, if \"the red greyhound\" was the nickname of a man\nextremely swift of foot (celebrated runners have been nicknamed\n\"greyhound\" among ourselves), a story of this kind would naturally\narise; and if the metaphorical name was mistaken for the actual name,\nthere might result, as the idol of the race, a compound form appropriate\nto the story. We need not be surprised, then, at finding among the\nEgyptians the goddess Pasht represented as a woman with a lion's head,\nand the god Har-hat as a man with the head of a hawk. The Babylonian\ngods--one having the form of a man with an eagle's tail, and another\nuniting a human bust to a fish's body--no longer appear such\nunaccountable conceptions. We get feasible explanations, too, of\nsculptures representing sphinxes, winged human-headed bulls, etc.; as\nwell as of the stories about centaurs, satyrs, and the rest.\n\n       *       *       *       *       *\n\nAncient myths in general thus acquire meanings considerably different\nfrom those ascribed to them by comparative mythologists. Though these\nlast may be in part correct, yet if the foregoing argument is valid,\nthey can scarcely be correct in their main outlines. Indeed, if we read\nthe facts the other way upward, regarding as secondary or additional,\nthe elements that are said to be primary, while we regard as primary,\ncertain elements which are considered as accretions of later times, we\nshall, I think, be nearer the truth.\n\nThe current theory of the myth is that it has grown out of the habit of\nsymbolizing natural agents and processes, in terms of human\npersonalities and actions. Now, it may in the first place be remarked\nthat, though symbolization of this kind is common among civilized races,\nit is not common among races that are the most uncivilized. By existing\nsavages, surrounding objects, motions, and changes, are habitually used\nto convey ideas respecting human transactions. It needs but to read the\nspeech of an Indian chief to see that just as primitive men name one\nanother metaphorically after surrounding objects, so do they\nmetaphorically describe one another's doings as though they were the\ndoings of natural objects. But assuming a contrary habit of thought to\nbe the dominant one, ancient myths are explained as results of the\nprimitive tendency to symbolize inanimate things and their changes, by\nhuman beings and their doings.\n\nA kindred difficulty must be added. The change of verbal meaning from\nwhich the myth is said to arise, is a change opposite in kind to that\nwhich prevails in the earlier stages of linguistic development. It\nimplies a derivation of the concrete from the abstract; whereas at first\nabstracts are derived only from concretes: the concrete of abstracts\nbeing a subsequent process. In the words of Prof. Max Mueller, there are\n\"dialects spoken at the present day which have no abstract nouns, and\nthe more we go back in the history of languages, the smaller we find the\nnumber of these useful expressions\" (_Chips_, vol. ii., p. 54); or, as\nhe says more recently--\"Ancient words and ancient thoughts, for both go\ntogether, have not yet arrived at that stage of abstraction in which,\nfor instance, active powers, whether natural or supernatural, can be\nrepresented in any but a personal and more or less human form.\"\n(_Fraser's Magazine_, April, 1870.) Here the concrete is represented as\noriginal, and the abstract as derivative. Immediately afterward,\nhowever, Prof. Max Mueller, having given as examples of abstract nouns,\n\"day and night, spring and winter, dawn and twilight, storm and\nthunder,\" goes on to argue that, \"as long as people thought in language,\nit was simply impossible to speak of morning or evening, of spring and\nwinter, without giving to these conceptions something of an individual,\nactive, sexual, and at last, personal character.\" (_Chips_, vol. ii., p.\n55.) Here the concrete is derived from the abstract--the personal\nconception is represented as coming _after_ the impersonal conception;\nand through such transformation of the impersonal into the personal,\nProf. Max Mueller considers ancient myths to have arisen. How are these\npropositions reconcilable? One of two things must be said:--If\noriginally there were none of these abstract nouns, then the earliest\nstatements respecting the daily course of Nature were made in concrete\nterms--the personal elements of the myth were the primitive elements,\nand the impersonal expressions which are their equivalents came later.\nIf this is not admitted, then it must be held that, until after there\narose these abstract nouns, there were no current statements at all\nrespecting these most conspicuous objects and changes which the heavens\nand the earth present; and that the abstract nouns having been somehow\nformed, and rightly formed, and used without personal meanings,\nafterward became personalized--a process the reverse of that which\ncharacterizes early linguistic progress.\n\nNo such contradictions occur if we interpret myths after the manner that\nhas been indicated. Nay, besides escaping contradictions, we meet with\nunexpected solutions. The moment we try it, the key unlocks for us with\nease what seems a quite inexplicable fact, which the current hypothesis\ntakes as one of its postulates. Speaking of such words as sky and earth,\ndew and rain, rivers and mountains, as well as of the abstract nouns\nabove named, Prof. Max Mueller says--\"Now in ancient languages every one\nof these words had necessarily a termination expressive of gender, and\nthis naturally produced in the mind the corresponding idea of sex, so\nthat these names received not only an individual, but a sexual\ncharacter. There was no substantive which was not either masculine or\nfeminine; neuters being of later growth, and distinguishable chiefly in\nthe nominative.\" (_Chips_, vol. ii., p. 55.) And this alleged necessity\nfor a masculine or feminine implication is assigned as a part of the\nreason why these abstract nouns and collective nouns became\npersonalized. But should not a true theory of these first steps in the\nevolution of thought and language show us how it happened that men\nacquired the seemingly-strange habit of so framing their words for sky,\nearth, dew, rain, etc., as to make them indicative of sex? Or, at any\nrate, must it not be admitted that an interpretation which, instead of\nassuming this habit to be \"necessary,\" shows us how it results, thereby\nacquires an additional claim to acceptance? The interpretation I have\nindicated does this. If men and women are habitually nicknamed, and if\ndefects of language lead their descendants to regard themselves as\ndescendants of the things from which the names were taken, then\nmasculine or feminine genders will be ascribed to these things according\nas the ancestors named after them were men or women. If a beautiful\nmaiden known metaphorically as \"the Dawn,\" afterwards becomes the\nmother of some distinguished chief called \"the North Wind,\" it will\nresult that when, in course of time, the two have been mistaken for the\nactual dawn and the actual north wind, these will, by implication, be\nrespectively considered as male and female.\n\nLooking, now, at the ancient myths in general, their seemingly most\ninexplicable trait is the habitual combination of alleged human ancestry\nand adventures, with the possession of personalities otherwise figuring\nin the heavens and on the earth, with totally non-human attributes. This\nenormous incongruity, not the exception but the rule, the current theory\nfails to explain. Suppose it to be granted that the great terrestrial\nand celestial objects and agents naturally become personalized; it does\nnot follow that each of them shall have a specific human biography. To\nsay of some star that he was the son of this king or that hero, was born\nin a particular place, and when grown up carried off the wife of a\nneighbouring chief, is a gratuitous multiplication of incongruities\nalready sufficiently great; and is not accounted for by the alleged\nnecessary personalization of abstract and collective nouns. As looked at\nfrom our present stand-point, however, such traditions become quite\nnatural--nay, it is clear that they will necessarily arise. When a\nnickname has become a tribal name, it thereby ceases to be individually\ndistinctive; and, as already said, the process of nicknaming inevitably\ncontinues. It commences afresh with each child; and the nickname of each\nchild is both an individual name and a potential tribal name, which may\nbecome an actual tribal name if the individual is sufficiently\ncelebrated. Usually, then, there is a double set of distinctions; under\none of which the individual is known by his ancestral name, and under\nthe other of which he is known by a name suggestive of something\npeculiar to himself: just as we have seen happens among the Scotch\nclans. Consider, now, what will result when language has reached a\nstage of development such that it can convey the notion of naming, and\nis able, therefore, to preserve traditions of human ancestry. It will\nresult that the individual will be known both as the son of such and\nsuch a man by a mother whose name was so and so, and also as \"the Crab\",\nor \"the Bear\", or \"the Whirlwind\"--supposing one of these to be his\nnickname. Such joint use of nicknames and proper names occurs in every\nschool. Now, clearly, in advancing from the early state in which\nancestors become identified with the objects they are nicknamed after,\nto the state in which there are proper names that have lost their\nmetaphorical meanings, there must be passed through a state in which\nproper names, partially settled only, may or may not be preserved, and\nin which the new nicknames are still liable to be mistaken for actual\nnames. Under such conditions there will arise (especially in the case of\na distinguished man) this seemingly-impossible combination of human\nparentage with the possession of the non-human, or superhuman,\nattributes of the thing which gave the nickname. Another anomaly\nsimultaneously disappears. The warrior may have, and often will have, a\nvariety of complimentary nicknames--\"the powerful one,\" \"the destroyer,\"\netc. Supposing his leading nickname has been \"the Sun\"; then when he\ncomes to be identified by tradition with the sun, it will happen that\nthe sun will acquire his alternative descriptive titles--the swift one,\nthe lion, the wolf--titles not obviously appropriate to the sun, but\nquite appropriate to the warrior. Then there comes, too, an explanation\nof the remaining trait of such myths. When this identification of\nconspicuous persons, male and female, with conspicuous natural agents,\nhas become settled, there will in due course arise interpretations of\nthe actions of these agents in anthropomorphic terms. Suppose, for\ninstance, that Endymion and Selene, metaphorically named, the one after\nthe setting sun, the other after the moon, have had their human\nindividualities merged in those of the sun and moon, through\nmisinterpretation of metaphors; what will happen? The legend of their\nloves having to be reconciled with their celestial appearances and\nmotions, these will be spoken of as results of feeling and will; so that\nwhen the sun is going down in the west, while the moon in mid-heaven is\nfollowing him, the fact will be expressed by saying: \"Selene loves and\nwatches Endymion.\" Thus we obtain a consistent explanation of the myth\nwithout distorting it; and without assuming that it contains gratuitous\nfictions. We are enabled to accept the biographical part of it, if not\nas literal fact, still as having had fact for its root. We are helped to\nsee how, by an inevitable misinterpretation, there grew out of a more or\nless true tradition, this strange identification of its personages, with\nobjects and powers totally non-human in their aspects. And then we are\nshown how, from the attempt to reconcile in thought these contradictory\nelements of the myth, there arose the habit of ascribing the actions of\nthese non-human things to human motives.\n\nOne further verification may be drawn from facts which are obstacles to\nthe converse hypothesis. These objects and powers, celestial and\nterrestrial, which force themselves most on men's attention, have some\nof them several proper names, identified with those of different\nindividuals, born at different places, and having different sets of\nadventures. Thus we have the sun variously known as Apollo, Endymion,\nHelios, Tithonos, etc.--personages having irreconcilable genealogies.\nSuch anomalies Prof. Max Mueller apparently ascribes to the\nuntrustworthiness of traditions, which are \"careless about\ncontradictions, or ready to solve them sometimes by the most atrocious\nexpedients.\" (_Chips_, vol. ii., p. 84.) But if the evolution of the\nmyth has been that above indicated, there exists no anomalies to be got\nrid of: these diverse genealogies become parts of the evidence. For we\nhave abundant proof that the same objects furnish metaphorical names of\nmen in different tribes. There are Duck tribes in Australia, in South\nAmerica, in North America. The eagle is still a totem among the North\nAmericans, as Mr. McLennan shows reason to conclude that it was among\nthe Egyptians, among the Jews, and among the Romans. Obviously, for\nreasons already assigned, it naturally happened in the early stages of\nthe ancient races, that complimentary comparisons of their heroes to the\nSun were frequently made. What resulted? The Sun having furnished names\nfor sundry chiefs and early founders of tribes, and local traditions\nhaving severally identified them with the Sun, these tribes, when they\ngrew, spread, conquered, or came otherwise into partial union,\noriginated a combined mythology, which necessarily contained conflicting\nstories about the Sun-god, as about its other leading personages. If the\nNorth-American tribes, among several of which there are traditions of a\nSun-god, had developed a combined civilization, there would similarly\nhave arisen among them a mythology which ascribed to the Sun several\ndifferent proper names and genealogies.\n\n       *       *       *       *       *\n\nLet me briefly set down the leading characters of this hypothesis which\ngive it probability.\n\nTrue interpretations of all the natural processes, organic and\ninorganic, that have gone on in past times, habitually trace them to\ncauses still in action. It is thus in Geology; it is thus in Biology; it\nis thus in Philology. Here we find this characteristic repeated.\nNicknaming, the inheritance of nicknames, and to some extent, the\nmisinterpretation of nicknames, go on among us still; and were surnames\nabsent, language imperfect, and knowledge as rudimentary as of old, it\nis tolerably manifest that results would arise like those we have\ncontemplated.\n\nA further characteristic of a true cause is that it accounts not only\nfor the particular group of phenomena to be interpreted, but also for\nother groups. The cause here alleged does this. It equally well explains\nthe worship of animals, of plants, of mountains, of winds, of celestial\nbodies, and even of appearances too vague to be considered entities. It\ngives us an intelligible genesis of fetichistic conceptions in general.\nIt furnishes us with a reason for the practice, otherwise so\nunaccountable, of moulding the words applied to inanimate objects in\nsuch ways as to imply masculine and feminine genders. It shows us how\nthere naturally arose the worship of compound animals, and of monsters\nhalf man, half brute. And it shows us why the worship of purely\nanthropomorphic deities came later, when language had so far developed\nthat it could preserve in tradition the distinction between proper names\nand nicknames.\n\nA further verification of this view is, that it conforms to the general\nlaw of evolution: showing us how, out of one simple, vague, aboriginal\nform of belief, there have arisen, by continuous differentiations, the\nmany heterogeneous forms of belief which have existed and do exist. The\ndesire to propitiate the other self of the dead ancestor, displayed\namong savage tribes, dominantly manifested by the early historic races,\nby the Peruvians and Mexicans, by the Chinese at the present time, and\nto a considerable degree by ourselves (for what else is the wish to do\nthat which a lately-deceased parent was known to have desired?) has been\nthe universal first form of religious belief; and from it have grown up\nthe many divergent beliefs which have been referred to.\n\nLet me add, as a further reason for adopting this view, that it\nimmensely diminishes the apparently-great contrast between early modes\nof thought and our own mode of thought. Doubtless the aboriginal man\ndiffers considerably from us, both in intellect and feeling. But such an\ninterpretation of the facts as helps us to bridge over the gap, derives\nadditional likelihood from doing this. The hypothesis I have sketched\nout enables us to see that primitive ideas are not so gratuitously\nabsurd as we suppose, and also enables us to rehabilitate the ancient\nmyth with far less distortion than at first sight appears possible.\n\nThese views I hope to develop in the first part of _The Principles of\nSociology_. The large mass of evidence which I shall be able to give in\nsupport of the hypothesis, joined with the solutions it will be shown to\nyield of many minor problems which I have passed over, will, I think,\nthen give to it a still greater probability than it seems now to have.\n\nFOOTNOTES:\n\n[Footnote 29: A critical reader may raise an objection. If\nanimal-worship is to be rationally interpreted, how can the\ninterpretation set out by assuming a belief in the spirits of dead\nancestors--a belief which just as much requires explanation? Doubtless\nthere is here a wide gap in the argument. I hope eventually to fill it\nup. Here, out of many experiences which conspire to generate this\nbelief, I can but briefly indicate the leading ones: 1. It is not\nimpossible that his shadow, following him everywhere, and moving as he\nmoves, may have some small share in giving to the savage a vague idea of\nhis duality. It needs but to watch a child's interest in the movements\nof its shadow, and to remember that at first a shadow cannot be\ninterpreted as a negation of light, but is looked upon as an entity, to\nperceive that the savage may very possibly consider it as a specific\nsomething which forms part of him. 2. A much more decided suggestion of\nthe same kind is likely to result from the reflection of his face and\nfigure in water: imitating him as it does in his form, colours, motions,\ngrimaces. When we remember that not unfrequently a savage objects to\nhave his portrait taken, because he thinks whoever carries away a\nrepresentation of him carries away some part of his being, we see how\nprobable it is that he thinks his double in the water is a reality in\nsome way belonging to him. 3. Echoes must greatly tend to confirm the\nidea of duality otherwise arrived at. Incapable as he is of\nunderstanding their natural origin, the primitive man necessarily\nascribes them to living beings--beings who mock him and elude his\nsearch. 4. The suggestions resulting from these and other physical\nphenomena are, however, secondary in importance. The root of this belief\nin another self lies in the experience of dreams. The distinction so\neasily made by us between our life in dreams and our real life, is one\nwhich the savage recognizes in but a vague way; and he cannot express\neven that distinction which he perceives. When he awakes, and to those\nwho have seen him lying quietly asleep, describes where he has been, and\nwhat he has done, his rude language fails to state the difference\nbetween seeing and dreaming that he saw, doing and dreaming that he did.\nFrom this inadequacy of his language it not only results that he cannot\ntruly represent this difference to others, but also that he cannot truly\nrepresent it to himself. Hence, in the absence of an alternative\ninterpretation, his belief, and that of those to whom he tells his\nadventures, is that his other self has been away, and came back when he\nawoke. And this belief, which we find among various existing savage\ntribes, we equally find in the traditions of the early civilized races.\n5. The conception of another self capable of going away and returning,\nreceives what to the savage must seem conclusive verifications from the\nabnormal suspensions of consciousness, and derangements of\nconsciousness, that occasionally occur in members of his tribe. One who\nhas fainted, and cannot be immediately brought back to himself (note the\nsignificance of our own phrases \"returning to himself,\" etc.) as a\nsleeper can, shows him a state in which the other self has been away for\na time beyond recall. Still more is this prolonged absence of the other\nself shown him in cases of apoplexy, catalepsy, and other forms of\nsuspended animation. Here for hours the other self persists in remaining\naway, and on returning refuses to say where he has been. Further\nverification is afforded by every epileptic subject, into whose body,\nduring the absence of the other self, some enemy has entered; for how\nelse does it happen that the other self, on returning, denies all\nknowledge of what his body has been doing? And this supposition that the\nbody has been \"possessed\" by some other being, is confirmed by the\nphenomena of somnambulism and insanity. 6. What, then, is the\ninterpretation inevitably put upon death? The other self has habitually\nreturned after sleep, which simulates death. It has returned, too, after\nfainting, which simulates death much more. It has even returned after\nthe rigid state of catalepsy, which simulates death very greatly. Will\nit not return also after this still more prolonged quiescence and\nrigidity? Clearly it is quite possible--quite probable even. The dead\nman's other self is gone away for a long time, but it still exists\nsomewhere, far or near, and may at any moment come back to do all he\nsaid he would do. Hence the various burial-rites--the placing of weapons\nand valuables along with the body, the daily bringing of food to it,\netc. I hope hereafter to show that, with such knowledge of the facts as\nhe has, this interpretation is the most reasonable the savage can arrive\nat. Let me here, however, by way of showing how clearly the facts bear\nout this view, give one illustration out of many. \"The ceremonies with\nwhich they [the Veddahs] invoke them [the shades of the dead] are few as\nthey are simple. The most common is the following. An arrow is fixed\nupright in the ground, and the Veddah dances slowly round it, chanting\nthis invocation, which is almost musical in its rhythm:\"\n\n     \"Ma miya, ma miy, ma deya,\n     Topang koyihetti mittigan yandah?\"\n\n   \"My departed one, my departed one, my God!\n   Where art thou wandering?\"\n\n\"This invocation appears to be used on all occasions when the\nintervention of the guardian spirits is required, in sickness,\npreparatory to hunting, etc. Sometimes, in the latter case, a portion of\nthe flesh of the game is promised as a votive offering, in the event of\nthe chase being successful; and they believe that the spirits will\nappear to them in dreams and tell them where to hunt. Sometimes they\ncook food and place it in the dry bed of a river, or some other secluded\nspot, and then call on their deceased ancestors by name. 'Come and\npartake of this! Give us maintenance as you did when living! Come,\nwheresoever you may be; on a tree, on a rock, in the forest, come!' And\nthey dance round the food, half chanting, half shouting, the\ninvocation.\"--Bailey, in _Transactions of the Ethnological Society_,\nLondon, N. S., ii., p. 301-2.]\n\n[Footnote 30: Since the foregoing pages were written, my attention has\nbeen drawn by Sir John Lubbock to a passage in the appendix to the\nsecond edition of _Prehistoric Times_, in which he has indicated this\nderivation of tribal names. He says: \"In endeavouring to account for the\nworship of animals, we must remember that names are very frequently\ntaken from them. The children and followers of a man called the Bear or\nthe Lion would make that a tribal name. Hence the animal itself would be\nfirst respected, at last worshipped.\" Of the genesis of this worship,\nhowever, Sir John Lubbock does not give any specific explanation.\nApparently he inclines to the belief, tacitly adopted also by Mr.\nMcLennan, that animal-worship is derived from an original Fetichism, of\nwhich it is a more developed form. As will shortly be seen, I take a\ndifferent view of its origin.]\n\n[Footnote 31: _Proceedings of the Royal Society of Tasmania_, iii., p.\n280-81.]\n\n[Footnote 32: I have since found, however, that the name Dawn, which\noccurs in various places, seems more frequently a birth-name, given\nbecause the birth took place at dawn.]\n\n\n\n\nMORALS AND MORAL SENTIMENTS.\n\n    [_First published in_ The Fortnightly Review _for April,_ 1871.]\n\n\nIf a writer who discusses unsettled questions takes up every gauntlet\nthrown down to him, polemical writing will absorb much of his energy.\nHaving a power of work which unfortunately does not suffice for\nexecuting with anything like due rapidity the task I have undertaken, I\nhave made it a policy to avoid controversy as much as possible, even at\nthe cost of being seriously misunderstood. Hence it resulted that when\nin _Macmillan's Magazine_, for July, 1869, Mr. Richard Hutton published,\nunder the title \"A Questionable Parentage for Morals,\" a criticism on a\ndoctrine of mine, I decided to let his misrepresentations pass unnoticed\nuntil, in the course of my work, I arrived at the stage where, by a full\nexposition of this doctrine, they would be set aside. It did not occur\nto me that, in the meantime, these erroneous statements, accepted as\ntrue statements, would be repeated by other writers, and my views\ncommented upon as untenable. This, however, has happened. In more\nperiodicals than one, I have seen it asserted that Mr. Hutton has\neffectually disposed of my hypothesis. Supposing that this hypothesis\nhas been rightly expressed by Mr. Hutton, Sir John Lubbock, in his\n_Origin of Civilisation_, &c., has been led to express a partial\ndissent; which I think he would not have expressed had my own\nexposition been before him. Mr. Mivart, too, in his recent _Genesis of\nSpecies_, has been similarly betrayed into misapprehensions. And now Sir\nAlexander Grant, following the same lead, has conveyed to the readers of\nthe _Fortnightly Review_ another of these conceptions, which is but very\npartially true. Thus I find myself compelled to say as much as will\nserve to prevent further spread of the mischief.\n\n       *       *       *       *       *\n\nIf a general doctrine concerning a highly-involved class of phenomena\ncould be adequately presented in a single paragraph of a letter, the\nwriting of books would be superfluous. In the brief exposition of\ncertain ethical doctrines held by me, which is given in Professor Bain's\n_Mental and Moral Science_, it is stated that they are--\n\n     \"as yet, nowhere fully expressed. They form part of the more\n     general doctrine of Evolution which he is engaged in working out;\n     and they are at present to be gathered only from scattered\n     passages. It is true that, in his first work, _Social Statics_, he\n     presented what he then regarded as a tolerably complete view of one\n     division of Morals. But without abandoning this view, he now\n     regards it as inadequate--more especially in respect of its basis.\"\n\nMr. Hutton, however, taking the bare enunciation of one part of this\nbasis, deals with it critically; and, in the absence of any exposition\nby me, sets forth what he supposes to be my grounds for it, and proceeds\nto show that they are unsatisfactory.\n\nIf, in his anxiety to suppress what he doubtless regards as a pernicious\ndoctrine, Mr. Hutton could not wait until I had explained myself, it\nmight have been expected that he would use whatever information was to\nbe had concerning it. So far from seeking out such information, however,\nhe has, in a way for which I cannot account, ignored the information\nimmediately before him.\n\nThe title which Mr. Hutton has chosen for his criticism is, \"A\nQuestionable Parentage for Morals.\" Now he has ample means of knowing\nthat I allege a primary basis of Morals, quite independent of that\nwhich he describes and rejects. I do not refer merely to the fact that\nhaving, when he reviewed _Social Statics_,[33] expressed his very\ndecided dissent from this primary basis, he must have been aware that I\nalleged it; for he may say that in the many years which have since\nelapsed he had forgotten all about it. But I refer to the distinct\nenunciation of this primary basis in that letter to Mr. Mill from which\nhe quotes. In a preceding paragraph of the letter, I have explained\nthat, while I accept utilitarianism in the abstract, I do not accept\nthat current utilitarianism which recognizes for the guidance of conduct\nnothing beyond empirical generalizations; and I have contended that--\n\n     \"Morality, properly so-called--the science of right conduct--has\n     for its object to determine _how_ and _why_ certain modes of\n     conduct are detrimental, and certain other modes beneficial. These\n     good and bad results cannot be accidental, but must be necessary\n     consequences of the constitution of things; and I conceive it to be\n     the business of Moral Science to deduce, from the laws of life and\n     the conditions of existence, what kinds of action necessarily tend\n     to produce happiness, and what kinds to produce unhappiness. Having\n     done this, its deductions are to be recognised as laws of conduct;\n     and are to be conformed to irrespective of a direct estimation of\n     happiness or misery.\"\n\nNor is this the only enunciation of what I conceive to be the primary\nbasis of morals, contained in this same letter. A subsequent paragraph\nseparated by four lines only from that which Mr. Hutton extracts,\ncommences thus:--\n\n    \"Progressing civilization, which is of necessity a succession of\n    compromises between old and new, requires a perpetual re-adjustment\n    of the compromise between the ideal and the practicable in social\n    arrangements: to which end, both elements of the compromise must be\n    kept in view. If it is true that pure rectitude prescribes a system\n    of things far too good for men as they are, it is not less true that\n    mere expediency does not of itself tend to establish a system of\n    things any better than that which exists. While absolute morality\n    owes to expediency the checks which prevent it from rushing into\n    Utopian absurdities, expediency is indebted to absolute morality for\n    all stimulus to improvement. Granted that we are chiefly interested\n    in ascertaining what is _relatively right_, it still follows that we\n     must first consider what is _absolutely right_; since the one\n    conception presupposes the other.\"\n\nI do not see how there could well be a more emphatic assertion that\nthere exists a primary basis of morals independent of, and in a sense\nantecedent to, that which is furnished by experiences of utility; and\nconsequently, independent of, and, in a sense antecedent to, those moral\nsentiments which I conceive to be generated by such experiences. Yet no\none could gather from Mr. Hutton's article that I assert this; or would\neven find reasons for a faint suspicion that I do so. From the reference\nmade to my further views, he would infer my acceptance of that empirical\nutilitarianism which I have expressly repudiated. And the title which\nMr. Hutton gives to his paper clearly asserts, by implication, that I\nrecognize no \"parentage for morals\" beyond that of the accumulation and\norganization of the effects of experience. I cannot believe that Mr.\nHutton intended to convey this erroneous impression. He was, I suppose,\ntoo much absorbed in contemplating the proposition he combats to\nobserve, or, at least, to attach any weight to, the propositions which\naccompany it. But I am sorry he did not perceive the mischief he was\nlikely to do me by spreading this one-sided statement.\n\n       *       *       *       *       *\n\nI pass now to the particular question at issue--not the \"parentage for\nmorals,\" but the parentage of moral sentiments. In describing my view on\nthis more special doctrine, Mr. Hutton has similarly, I regret to say,\nneglected the data which would have helped him to draw an approximately\ntrue outline of it. It cannot well be that the existence of such data\nwas unknown to him. They are contained in the _Principles of\nPsychology_; and Mr. Hutton reviewed that work when it was first\npublished.[34] In a chapter on the Feelings, which occurs near the end\nof it, there is sketched out a process of evolution by no means like\nthat which Mr. Hutton indicates; and had he turned to that chapter he\nwould have seen that his description of the genesis of moral sentiments\nout of organized experiences is not such a one as I should have given.\nLet me quote a passage from that chapter.\n\n     \"Not only are those emotions which form the immediate stimuli to\n     actions, thus explicable; but the like explanation applies to the\n     emotions that leave the subject of them comparatively passive: as,\n     for instance, the emotion produced by beautiful scenery. The\n     gradually increasing complexity in the groups of sensations and\n     ideas co-ordinated, ends in the co-ordination of those vast\n     aggregations of them which a grand landscape excites and suggests.\n     The infant taken into the midst of mountains, is totally unaffected\n     by them; but is delighted with the small group of attributes and\n     relations presented in a toy. The child can appreciate, and be\n     pleased with, the more complicated relations of household objects\n     and localities, the garden, the field, and the street. But it is\n     only in youth and mature age, when individual things and small\n     assemblages of them have become familiar and automatically\n     cognizable, that those immense assemblages which landscapes present\n     can be adequately grasped, and the highly aggregated states of\n     consciousness produced by them, experienced. Then, however, the\n     various minor groups of states that have been in earlier days\n     severally produced by trees, by fields, by streams, by cascades, by\n     rocks, by precipices, by mountains, by clouds, are aroused\n     together. Along with the sensations immediately received, there are\n     partially excited the myriads of sensations that have been in times\n     past received from objects such as those presented; further, there\n     are partially excited the various incidental feelings that were\n     experienced on all these countless past occasions; and there are\n     probably also excited certain deeper, but now vague combinations of\n     states, that were organized in the race during barbarous times,\n     when its pleasurable activities were chiefly among the woods and\n     waters. And out of all these excitations, some of them actual but\n     most of them nascent, is composed the emotion which a fine\n     landscape produces in us.\"\n\nIt is, I think, amply manifest that the processes here indicated are not\nto be taken as intellectual processes--not as processes in which\nrecognized relations between pleasures and their antecedents, or\nintelligent adaptations of means to ends, form the dominant elements.\nThe state of mind produced by an aggregate of picturesque objects is not\none resolvable into propositions. The sentiment does not contain within\nitself any consciousness of causes and consequences of happiness. The\nvague recollections of other beautiful scenes and other delightful days\nwhich it dimly rouses, are not aroused because of any rational\nco-ordinations of ideas that have been formed in bygone years. Mr.\nHutton, however, assumes that in speaking of the genesis of moral\nfeelings as due to inherited experiences of the pleasures and pains\ncaused by certain modes of conduct, I am speaking of reasoned-out\nexperiences--experiences consciously accumulated and generalized. He\noverlooks the fact that the genesis of emotions is distinguished from\nthe genesis of ideas in this; that whereas the ideas are composed of\nelements that are simple, definitely related, and (in the case of\ngeneral ideas) constantly related, emotions are composed of enormously\ncomplex aggregates of elements that are never twice alike, and which\nstand in relations that are never twice alike. The difference in the\nresulting modes of consciousness is this:--In the genesis of an idea the\nsuccessive experiences, be they of sounds, colours, touches, tastes, or\nbe they of the special objects which combine many of these into groups,\nhave so much in common that each, when it occurs, can be definitely\nthought of as like those which preceded it. But in the genesis of an\nemotion the successive experiences so far differ that each of them, when\nit occurs, suggests past experiences which are not specifically similar,\nbut have only a general similarity; and, at the same time, it suggests\nbenefits or evils in past experience which likewise are various in their\nspecial natures, though they have a certain community in general nature.\nHence it results that the consciousness aroused is a multitudinous,\nconfused consciousness, in which, along with a certain kind of\ncombination among the impressions received from without, there is a\nvague cloud of ideal combinations akin to them, and a vague mass of\nideal feelings of pleasure or pain which were associated with these. We\nhave abundant proof that feelings grow up without reference to\nrecognized causes and consequences, and without the possessor of them\nbeing able to say why they have grown up; though analysis,\nnevertheless, shows that they have been formed out of connected\nexperiences. The familiar fact that a kind of jam which was, during\nchildhood, repeatedly taken after medicine, may become, by simple\nassociation of sensations, so nauseous that it cannot be tolerated in\nafter-life, illustrates clearly the way in which repugnances may be\nestablished by habitual association of feelings, without any belief in\ncausal connexion; or rather, in spite of the knowledge that there is no\ncausal connexion. Similarly with pleasurable emotions. The cawing of\nrooks is not in itself an agreeable sound: musically considered, it is\nvery much the contrary. Yet the cawing of rooks usually produces in\npeople feelings of a grateful kind--feelings which most of them suppose\nto result from the quality of the sound itself. Only the few who are\ngiven to self-analysis are aware that the cawing of rooks is agreeable\nto them because it has been connected with countless of their greatest\ngratifications--with the gathering of wild flowers in childhood; with\nSaturday-afternoon excursions in school-boy days; with midsummer\nholidays in the country, when books were thrown aside and lessons were\nreplaced by games and adventures in the fields; with fresh, sunny\nmornings in after-years, when a walking excursion was an immense relief\nfrom toil. As it is, this sound, though not causally related to all\nthese multitudinous and varied past delights, but only often associated\nwith them, can no more be heard without rousing a dim consciousness of\nthese delights, than the voice of an old friend unexpectedly coming into\nthe house can be heard without suddenly raising a wave of that feeling\nthat has resulted from the pleasures of past companionship. If we are to\nunderstand the genesis of emotions, either in the individual or in the\nrace, we must take account of this all-important process. Mr. Hutton,\nhowever, apparently overlooking it, and not having reminded himself, by\nreferring to the _Principles of Psychology_, that I insist upon it,\nrepresents my hypothesis to be that a certain sentiment results from the\nconsolidation of intellectual conclusions! He speaks of me as believing\nthat \"what seems to us now the 'necessary' intuitions and _a priori_\nassumptions of human nature, are likely to prove, when scientifically\nanalysed, nothing but a similar conglomeration of our ancestors' _best\nobservations and most useful empirical rules_.\" He supposes me to think\nthat men having, in past times, come to _see_ that truthfulness was\nuseful, \"the habit of approving truth-speaking and fidelity to\nengagements, which was first based on this ground of utility, became so\nrooted, that the utilitarian ground of it was forgotten, and _we_ find\nourselves springing to the belief in truth-speaking and fidelity to\nengagements from an inherited tendency.\" Similarly throughout, Mr.\nHutton has so used the word \"utility,\" and so interpreted it on my\nbehalf, as to make me appear to mean that moral sentiment is formed out\nof _conscious generalizations_ respecting what is beneficial and what\ndetrimental. Were such my hypothesis, his criticisms would be very much\nto the point; but as such is not my hypothesis, they fall to the ground.\nThe experiences of utility I refer to are those which become registered,\nnot as distinctly recognized connexions between certain kinds of acts\nand certain kinds of remote results, but those which become registered\nin the shape of associations between groups of feelings that have often\nrecurred together, though the relation between them has not been\nconsciously generalized--associations the origin of which may be as\nlittle perceived as is the origin of the pleasure given by the sounds of\na rookery; but which, nevertheless, have arisen in the course of daily\nconverse with things, and serve as incentives or deterrents.\n\nIn the paragraph which Mr. Hutton has extracted from my letter to Mr.\nMill, I have indicated an analogy between those effects of emotional\nexperiences out of which I believe moral sentiments have been developed,\nand those effects of intellectual experiences out of which I believe\nspace-intuitions have been developed. Rightly considering that the first\nof these hypotheses cannot stand if the last is disproved, Mr. Hutton\nhas directed part of his attack against this last. But would it not have\nbeen well if he had referred to the _Principles of Psychology_, where\nthis last hypothesis is set forth at length, before criticising it?\nWould it not have been well to give an abstract of my own description of\nthe process, instead of substituting what he _supposes_ my description\nmust be? Any one who turns to the _Principles of Psychology_ (first\nedition, pp. 218-245), and reads the two chapters, \"The Perception of\nBody as presenting Statical Attributes\", and \"The Perception of Space\",\nwill find that Mr. Hutton's account of my view on this matter has given\nhim no notion of the view as it is expressed by me; and will, perhaps,\nbe less inclined to smile than he was when he read Mr. Hutton's account.\nI cannot here do more than thus imply the invalidity of such part of Mr.\nHutton's argument as proceeds upon this incorrect representation. The\npages which would be required for properly explaining the doctrine that\nspace-intuitions result from organized experiences may be better used\nfor explaining this analogous doctrine at present before us. This I will\nnow endeavour to do; not indirectly by correcting misapprehensions, but\ndirectly by an exposition which shall be as brief as the extremely\ninvolved nature of the process allows.\n\nAn infant in arms, when old enough to gaze at objects around with some\nvague recognition, smiles in response to the laughing face and soft\ncaressing voice of its mother. Let there come some one who, with an\nangry face, speaks to it in loud, harsh tones. The smile disappears, the\nfeatures contract into an expression of pain, and, beginning to cry, it\nturns away its head, and makes such movements of escape as are possible.\nWhat is the meaning of these facts? Why does not the frown make it\nsmile, and the mother's laugh make it weep? There is but one answer.\nAlready in its developing brain there is coming into play the structure\nthrough which one cluster of visual and auditory impressions excites\npleasurable feelings, and the structure through which another cluster of\nvisual and auditory impressions excites painful feelings. The infant\nknows no more about the relation existing between a ferocious expression\nof face, and the evils which may follow perception of it, than the young\nbird just out of its nest knows of the possible pain and death which may\nbe inflicted by a man coming towards it; and as certainly in the one\ncase as in the other, the alarm felt is due to a partially-established\nnervous structure. Why does this partially-established nervous structure\nbetray its presence thus early in the human being? Simply because, in\nthe past experiences of the human race, smiles and gentle tones in those\naround have been the habitual accompaniments of pleasurable feelings;\nwhile pains of many kinds, immediate and more or less remote, have been\ncontinually associated with the impressions received from knit brows,\nand set teeth, and grating voice. Much deeper down than the history of\nthe human race must we go to find the beginnings of these connexions.\nThe appearances and sounds which excite in the infant a vague dread,\nindicate danger; and do so because they are the physiological\naccompaniments of destructive action--some of them common to man and\ninferior mammals, and consequently understood by inferior mammals, as\nevery puppy shows us. What we call the natural language of anger, is due\nto a partial contraction of those muscles which actual combat would call\ninto play; and all marks of irritation, down to that passing shade over\nthe brow which accompanies slight annoyance, are incipient stages of\nthese same contractions. Conversely with the natural language of\npleasure, and of that state of mind which we call amicable feeling:\nthis, too, has a physiological interpretation.[35]\n\nLet us pass now from the infant in arms to the children in the nursery.\nWhat have the experiences of each been doing in aid of the emotional\ndevelopment we are considering? While its limbs have been growing more\nagile by exercise, its manipulative skill increasing by practice, its\nperceptions of objects growing by use quicker, more accurate, more\ncomprehensive; the associations between these two sets of impressions\nreceived from those around, and the pleasures and pains received along\nwith them, or after them, have been by frequent repetition made\nstronger, and their adjustments better. The dim sense of pain and the\nvague glow of delight which the infant felt, have, in the urchin,\nseverally taken shapes that are more definite. The angry voice of a\nnursemaid no longer arouses only a formless feeling of dread, but also a\nspecific idea of the slap that may follow. The frown on the face of a\nbigger brother, along with the primitive, indefinable sense of ill,\nbrings the ideas of ills that are definable as kicks, and cuffs, and\npullings of hair, and losses of toys. The faces of parents, looking now\nsunny, now gloomy, have grown to be respectively associated with\nmultitudinous forms of gratification and multitudinous forms of\ndiscomfort or privation. Hence these appearances and sounds, which imply\namity or enmity in those around, become symbolic of happiness and\nmisery; so that eventually, perception of the one set or the other can\nscarcely occur without raising a wave of pleasurable feeling or of\npainful feeling. The body of this wave is still substantially of the\nsame nature as it was at first; for though in each of these\nmultitudinous experiences a special set of facial and vocal signs has\nbeen connected with a special set of pleasures or pains; yet since these\npleasures or pains have been immensely varied in their kinds and\ncombinations, and since the signs that preceded them were in no two\ncases quite alike, it results that even to the end the consciousness\nproduced remains as vague as it is voluminous. The thousands of\npartially-aroused ideas resulting from past experiences are massed\ntogether and superposed, so as to form an aggregate in which nothing is\ndistinct, but which has the character of being pleasurable or painful\naccording to the nature of its original components: the chief difference\nbetween this developed feeling and the feeling aroused in the infant\nbeing, that on bright or dark background forming the body of it, may now\nbe sketched out in thought the particular pleasures or pains which the\nparticular circumstances suggest as likely.\n\nWhat must be the working of this process under the conditions of\naboriginal life? The emotions given to the young savage by the natural\nlanguage of love and hate in the members of his tribe, gain first a\npartial definiteness in respect to his intercourse with his family and\nplaymates; and he learns by experience the utility, in so far as his own\nends are concerned, of avoiding courses which call from others\nmanifestations of anger, and taking courses which call from them\nmanifestations of pleasure. Not that he consciously generalizes. He does\nnot at that age, probably not at any age, formulate his experiences in\nthe general principle that it is well for him to do things which bring\nsmiles, and to avoid doing things which bring frowns. What happens is\nthat having, in the way shown, inherited this connexion between the\nperception of anger in others and the feeling of dread, and having\ndiscovered that certain acts of his bring on this anger, he cannot\nsubsequently think of committing one of these acts without thinking of\nthe resulting anger, and feeling more or less of the resulting dread. He\nhas no thought of the utility or inutility of the act itself: the\ndeterrent is the mainly vague, but partially definite, fear of evil that\nmay follow. So understood, the deterring emotion is one which has grown\nout of experiences of utility, using that word in its ethical sense; and\nif we ask why this dreaded anger is called forth from others, we shall\nhabitually find that it is because the forbidden act entails pain\nsomewhere--is negatived by utility. On passing from domestic injunctions\nto injunctions current in the tribe, we see no less clearly how these\nemotions produced by approbation and reprobation come to be connected in\nexperience with actions which are beneficial to the tribe, and actions\nwhich are detrimental to the tribe; and how there consequently grow up\nincentives to the one class of actions and prejudices against the other\nclass. From early boyhood the young savage hears recounted the daring\ndeeds of his chief--hears them in words of praise, and sees all faces\nglowing with admiration. From time to time also he listens while some\none's cowardice is described in tones of scorn, and with contemptuous\nmetaphors, and sees him meet with derision and insult whenever he\nappears. That is to say, one of the things that come to be associated in\nhis mind with smiling faces, which are symbolical of pleasures in\ngeneral, is courage; and one of the things that come to be associated in\nhis mind with frowns and other marks of enmity, which form his symbol of\nunhappiness, is cowardice. These feelings are not formed in him because\nhe has reasoned his way to the truth that courage is useful to the\ntribe, and, by implication, to himself, or to the truth that cowardice\nis a cause of evil. In adult life he may perhaps see this; but he\ncertainly does not see it at the time when bravery is thus joined in his\nconsciousness with all that is good, and cowardice with all that is bad.\nSimilarly there are produced in him feelings of inclination or\nrepugnance towards other lines of conduct that have become established\nor interdicted, because they are beneficial or injurious to the tribe;\nthough neither the young nor the adults know why they have become\nestablished or interdicted. Instance the praiseworthiness of\nwife-stealing, and the viciousness of marrying within the tribe.\n\nWe may now ascend a stage to an order of incentives and restraints\nderived from these. The primitive belief is that every dead man becomes\na demon, who is often somewhere at hand, may at any moment return, may\ngive aid or do mischief, and has to be continually propitiated. Hence\namong other agents whose approbation or reprobation are contemplated by\nthe savage as consequences of his conduct, are the spirits of his\nancestors. When a child he is told of their deeds, now in triumphant\ntones, now in whispers of horror; and the instilled belief that they may\ninflict some vaguely-imagined but fearful evil, or give some great help,\nbecomes a powerful incentive or deterrent. Especially does this happen\nwhen the story is of a chief, distinguished for his strength, his\nferocity, his persistence in that revenge on enemies which the\nexperiences of the savage make him regard as beneficial and virtuous.\nThe consciousness that such a chief, dreaded by neighbouring tribes, and\ndreaded, too, by members of his own tribe, may reappear and punish those\nwho have disregarded his injunctions, becomes a powerful motive. But it\nis clear, in the first place, that the imagined anger and the imagined\nsatisfaction of this deified chief, are simply transfigured forms of the\nanger and satisfaction displayed by those around; and that the feelings\naccompanying such imaginations have the same original root in the\nexperiences which have associated an average of painful results with the\nmanifestation of another's anger, and an average of pleasurable results\nwith the manifestation of another's satisfaction. And it is clear, in\nthe second place, that the actions thus forbidden and encouraged must be\nmostly actions that are respectively detrimental and beneficial to the\ntribe; since the successful chief is usually a better judge than the\nrest, and has the preservation of the tribe at heart. Hence experiences\nof utility, consciously or unconsciously organized, underlie his\ninjunctions; and the sentiments which prompt obedience are, though very\nindirectly and without the knowledge of those who feel them, referable\nto experiences of utility.\n\nThis transfigured form of restraint, differing at first but little from\nthe original form, admits of immense development. Accumulating\ntraditions, growing in grandeur as they are repeated from generation to\ngeneration, make more and more superhuman the early-recorded hero of the\nrace. His powers of inflicting punishment and giving happiness become\never greater, more multitudinous, and more varied; so that the dread of\ndivine displeasure, and the desire to obtain divine approbation, acquire\na certain largeness and generality. Still the conceptions remain\nanthropomorphic. The revengeful deity continues to be thought of in\nterms of human emotions, and continues to be represented as displaying\nthese emotions in human ways. Moreover, the sentiments of right and\nduty, so far as they have become developed, refer mainly to divine\ncommands and interdicts; and have little reference to the natures of the\nacts commanded or interdicted. In the intended offering-up of Isaac, in\nthe sacrifice of Jephthah's daughter, and in the hewing to pieces of\nAgag, as much as in the countless atrocities committed from religious\nmotives by various early historic races, as by some existing savage\nraces, we see that the morality and immorality of actions, as we\nunderstand them, are at first little recognized; and that the feelings,\nchiefly of dread, which serve in place of them, are feelings felt\ntowards the unseen beings supposed to issue the commands and interdicts.\n\nHere it will be said that, as just admitted, these are not the moral\nsentiments properly so called. They are simply sentiments that precede\nand make possible those highest sentiments which do not refer either to\npersonal benefits or evils to be expected from men, or to more remote\nrewards and punishments. Several comments are, however, called forth by\nthis criticism. One is, that if we glance back at past beliefs and their\ncorrelative feelings, as shown in Dante's poem, in the mystery-plays of\nthe middle ages, in St. Bartholomew massacres, in burnings for heresy,\nwe get proof that in comparatively modern times right and wrong meant\nlittle else than subordination or insubordination--to a divine ruler\nprimarily, and under him to a human ruler. Another is, that down to our\nown day this conception largely prevails, and is even embodied in\nelaborate ethical works--instance the _Essays on the Principles of\nMorality_, by Jonathan Dymond, which recognizes no ground of moral\nobligation save the will of God as expressed in the current creed. And\nyet a further is, that while in sermons the torments of the damned and\nthe joys of the blessed are set forth as the dominant deterrents and\nincentives, and while we have prepared for us printed instructions \"how\nto make the best of both worlds,\" it cannot be denied that the feelings\nwhich impel and restrain men are still largely composed of elements like\nthose operative on the savage: the dread, partly vague, partly specific,\nassociated with the idea of reprobation, human and divine, and the sense\nof satisfaction, partly vague, partly specific, associated with the idea\nof approbation, human and divine.\n\nBut during the growth of that civilization which has been made possible\nby these ego-altruistic sentiments, there have been slowly evolving the\naltruistic sentiments. Development of these has gone on only as fast as\nsociety has advanced to a state in which the activities are mainly\npeaceful. The root of all the altruistic sentiments is sympathy; and\nsympathy could become dominant only when the mode of life, instead of\nbeing one that habitually inflicted direct pain, became one which\nconferred direct and indirect benefits: the pains inflicted being mainly\nincidental and indirect. Adam Smith made a large step towards this truth\nwhen he recognized sympathy as giving rise to these superior controlling\nemotions. His _Theory of Moral Sentiments_, however, requires to be\nsupplemented in two ways. The natural process by which sympathy becomes\ndeveloped into a more and more important element of human nature has to\nbe explained; and there has also to be explained the process by which\nsympathy produces the highest and most complex of the altruistic\nsentiments--that of justice. Respecting the first process, I can here do\nno more than say that sympathy may be proved, both inductively and\ndeductively, to be the concomitant of gregariousness: the two having all\nalong-increased by reciprocal aid. Multiplication has ever tended to\nforce into an association, more or less close, all creatures having\nkinds of food and supplies of food that permit association; and\nestablished psychological laws warrant the inference that some sympathy\nwill inevitably result from habitual manifestations of feelings in\npresence of one another, and that the gregariousness being augmented by\nthe increase of sympathy, further facilitates the development of\nsympathy. But there are negative and positive checks upon this\ndevelopment--negative, because sympathy cannot advance faster than\nintelligence advances, since it presupposes the power of interpreting\nthe natural language of the various feelings, and of mentally\nrepresenting those feelings; positive, because the immediate needs of\nself-preservation are often at variance with its promptings, as, for\nexample, during the predatory stages of human progress. For explanations\nof the second process, I must refer to the _Principles of Psychology_ (Sec.\n202, first edition, and Sec. 215, second edition) and to _Social Statics_,\npart ii. chapter v.[36] Asking that in default of space these\nexplanations may be taken for granted, let me here point out in what\nsense even sympathy, and the sentiments that result from it, are due to\nexperiences of utility. If we suppose all thought of rewards or\npunishments, immediate or remote, to be left out of consideration, it is\nclear that any one who hesitates to inflict a pain because of the vivid\nrepresentation of that pain which rises in his consciousness, is\nrestrained, not by any sense of obligation or by any formulated doctrine\nof utility, but by the painful association established in him. And it is\nclear that if, after repeated experiences of the moral discomfort he has\nfelt from witnessing the unhappiness indirectly caused by some of his\nacts, he is led to check himself when again tempted to those acts, the\nrestraint is of like nature. Conversely with the pleasure-giving acts:\nrepetitions of kind deeds, and experiences of the sympathetic\ngratifications that follow, tend continually to make stronger the\nassociation between such deeds and feelings of happiness.\n\nEventually these experiences may be consciously generalized, and there\nmay result a deliberate pursuit of sympathetic gratifications. There may\nalso come to be distinctly recognized the truths that the remoter\nresults, kind and unkind conduct, are respectively beneficial and\ndetrimental--that due regard for others is conducive to ultimate\npersonal welfare, and disregard of others to ultimate personal disaster;\nand then there may become current such summations of experience as\n\"honesty is the best policy.\" But so far from regarding these\nintellectual recognitions of utility as preceding and causing the moral\nsentiment, I regard the moral sentiment as preceding such recognitions\nof utility, and making them possible. The pleasures and pains directly\nresulting in experience from sympathetic and unsympathetic actions, had\nfirst to be slowly associated with such actions, and the resulting\nincentives and deterrents frequently obeyed, before there could arise\nthe perceptions that sympathetic and unsympathetic actions are remotely\nbeneficial or detrimental to the actor; and they had to be obeyed still\nlonger and more generally before there could arise the perceptions that\nthey are socially beneficial or detrimental. When, however, the remote\neffects, personal and social, have gained general recognition, are\nexpressed in current maxims, and lead to injunctions having the\nreligious sanction, the sentiments that prompt sympathetic actions and\ncheck unsympathetic ones are immensely strengthened by their alliances.\nApprobation and reprobation, divine and human, come to be associated in\nthought with the sympathetic and unsympathetic actions respectively. The\ncommands of the creed, the legal penalties, and the code of social\nconduct, unitedly enforce them; and every child as it grows up, daily\nhas impressed on it by the words and faces and voices of those around\nthe authority of these highest principles of conduct. And now we may see\nwhy there arises a belief in the special sacredness of these highest\nprinciples, and a sense of the supreme authority of the altruistic\nsentiments answering to them. Many of the actions which, in early social\nstates, received the religious sanction and gained public approbation,\nhad the drawback that such sympathies as existed were outraged, and\nthere was hence an imperfect satisfaction. Whereas these altruistic\nactions, while similarly having the religious sanction and gaining\npublic approbation, bring a sympathetic consciousness of pleasure given\nor of pain prevented; and, beyond this, bring a sympathetic\nconsciousness of human welfare at large, as being furthered by making\naltruistic actions habitual. Both this special and this general\nsympathetic consciousness become stronger and wider in proportion as the\npower of mental representation increases, and the imagination of\nconsequences, immediate and remote, grows more vivid and comprehensive.\nUntil at length these altruistic sentiments begin to call in question\nthe authority of those ego-altruistic sentiments which once ruled\nunchallenged. They prompt resistance to laws that do not fulfil the\nconception of justice, encourage men to brave the frowns of their\nfellows by pursuing a course at variance with customs that are perceived\nto be socially injurious, and even cause dissent from the current\nreligion; either to the extent of disbelief in those alleged divine\nattributes and acts not approved by this supreme moral arbiter, or to\nthe extent of entire rejection of a creed which ascribes such attributes\nand acts.\n\nMuch that is required to make this hypothesis complete must stand over\nuntil, at the close of the second volume of the _Principles of\nPsychology_, I have space for a full exposition. What I have said will\nmake it sufficiently clear that two fundamental errors have been made in\nthe interpretation put upon it. Both Utility and Experience have been\nconstrued in senses much too narrow. Utility, convenient a word as it is\nfrom its comprehensiveness, has very inconvenient and misleading\nimplications. It vividly suggests uses, and means, and proximate ends,\nbut very faintly suggests the pleasures, positive or negative, which are\nthe ultimate ends, and which, in the ethical meaning of the word, are\nalone considered; and, further, it implies conscious recognition of\nmeans and ends--implies the deliberate taking of some course to gain a\nperceived benefit. Experience, too, in its ordinary acceptation,\nconnotes definite perceptions of causes and consequences, as standing in\nobserved relations, and is not taken to include the connexions formed in\nconsciousness between states that recur together, when the relation\nbetween them, causal or other, is not perceived. It is in their widest\nsenses, however, that I habitually use these words, as will be manifest\nto every one who reads the _Principles of Psychology;_ and it is in\ntheir widest senses that I have used them in the letter to Mr. Mill. I\nthink I have shown above that, when they are so understood, the\nhypothesis briefly set forth in that letter is by no means so\nindefensible as is supposed. At any rate, I have shown--what seemed for\nthe present needful to show--that Mr. Hutton's versions of my views must\nnot be accepted as correct.\n\nFOOTNOTES:\n\n[Footnote 33: See _Prospective Review_ for January, 1852.]\n\n[Footnote 34: His criticism will be found in the _National Review_ for\nJanuary, 1856, under the title \"Atheism.\"]\n\n[Footnote 35: Hereafter I hope to elucidate at length these phenomena of\nexpression. For the present, I can refer only to such further\nindications as are contained in two essays on \"The Physiology of\nLaughter\" and \"The Origin and Function of Music.\"]\n\n[Footnote 36: I may add that in _Social Statics_, chap. xxx., I have\nindicated, in a general way, the causes of the development of sympathy\nand the restraints upon its development--confining the discussion,\nhowever, to the case of the human race, my subject limiting me to that.\nThe accompanying teleology I now disclaim.]\n\n\n\n\nTHE COMPARATIVE PSYCHOLOGY OF MAN.\n\n    [_Originally read before the Anthropological Institute, and\n    afterwards published in _Mind, _for January,_ 1876.]\n\n\nWhile discussing with two members of the Anthropological Institute the\nwork to be undertaken by its psychological section, I made certain\nsuggestions which they requested me to put in writing. When reminded,\nsome months after, of the promise I had made to do this, I failed to\nrecall the particular suggestions referred to; but in the endeavour to\nremember them, I was led to glance over the whole subject of comparative\nhuman psychology. Hence resulted the following paper.\n\nThat making a general survey is useful as a preliminary to deliberate\nstudy, either of a whole or of any part, scarcely needs showing.\nVagueness of thought accompanies the wandering about in a region without\nknown bounds or landmarks. Attention devoted to some portion of a\nsubject in ignorance of its connexion with the rest, leads to untrue\nconceptions. The whole cannot be rightly conceived without some\nknowledge of the parts; and no part can be rightly conceived out of\nrelation to the whole.\n\nTo map out the Comparative Psychology of Man must also conduce to the\nmore methodic carrying on of inquiries. In this, as in other things,\ndivision of labour will facilitate progress; and that there may be\ndivision of labour, the work itself must be systematically divided.\n\nWe may conveniently separate the entire subject into three main\ndivisions, and may arrange them in the order of increasing speciality.\n\nThe first division will treat of the degrees of mental evolution of\ndifferent human types, generally considered: taking account of both the\nmass of mental manifestation and the complexity of mental manifestation.\nThis division will include the relations of these characters to physical\ncharacters--the bodily mass and structure, and the cerebral mass and\nstructure. It will also include inquiries concerning the time taken in\ncompleting mental evolution, and the time during which adult mental\npower lasts; as well as certain most general traits of mental action,\nsuch as the greater or less persistence of emotions and of intellectual\nprocesses. The connexion between the general mental type and the general\nsocial type should also be here dealt with.\n\nIn the second division may be conveniently placed apart, inquiries\nconcerning the relative mental natures of the sexes in each race. Under\nit will come such questions as these:--What differences of mental mass\nand mental complexity, if any, existing between males and females, are\ncommon to all races? Do such differences vary in degree, or in kind, or\nin both? Are there reasons for thinking that they are liable to change\nby increase or decrease? What relations do they bear in each case to the\nhabits of life, the domestic arrangements, and the social arrangements?\nThis division should also include in its scope the sentiments of the\nsexes towards one another, considered as varying quantitatively and\nqualitatively; as well as their respective sentiments towards offspring,\nsimilarly varying.\n\nFor the third division of inquiries may be reserved the more special\nmental traits distinguishing different types of men. One class of such\nspecialities results from differences of proportion among faculties\npossessed in common; and another class results from the presence in some\nraces of faculties that are almost or quite absent from others. Each\ndifference in each of these groups, when established by comparison, has\nto be studied in connexion with the stage of mental evolution reached,\nand has to be studied in connexion with the habits of life and the\nsocial development, regarding it as related to these both as cause and\nas consequence.\n\nSuch being the outlines of these several divisions, let us now consider\nin detail the subdivisions contained within each.\n\n       *       *       *       *       *\n\nI.--Under the head of general mental evolution we may begin with the\ntrait of--\n\n1. _Mental mass._--Daily experiences show us that human beings differ in\nvolume of mental manifestation. Some there are whose intelligence, high\nthough it may be, produces little impression on those around; while\nthere are some who, when uttering even commonplaces, do it so as to\naffect listeners in a disproportionate degree. Comparison of two such,\nmakes it manifest that, generally, the difference is due to the natural\nlanguage of the emotions. Behind the intellectual quickness of the one\nthere is not felt any power of character; while the other betrays a\nmomentum capable of bearing down opposition--a potentiality of emotion\nthat has something formidable about it. Obviously the varieties of\nmankind differ much in respect of this trait. Apart from kind of\nfeeling, they are unlike in amount of feeling. The dominant races\noverrun the inferior races mainly in virtue of the greater quantity of\nenergy in which this greater mental mass shows itself. Hence a series of\ninquiries, of which these are some:--(_a_) What is the relation between\nmental mass and bodily mass? Manifestly, the small races are deficient\nin it. But it also appears that races much upon a par in size--as, for\ninstance, an Englishman and a Damara, differ considerably in mental\nmass. (_b_) What is its relation to mass of brain? and, bearing in mind\nthe general law that in the same species, size of brain increases with\nsize of body (though not in the same proportion), how far can we connect\nthe extra mental mass of the higher races, with an extra mass of brain\nbeyond that which is proper to their greater bodily mass? (_c_) What\nrelation, if any, is there between mental mass and the physiological\nstate expressed in vigour of circulation and richness of blood, as\nseverally determined by mode of life and general nutrition? (_d_) What\nare the relations of this trait to the social state, as nomadic or\nsettled, predatory or industrial?\n\n2. _Mental complexity._--How races differ in respect of the more or less\ninvolved structures of their minds, will best be understood on recalling\nthe unlikeness between the juvenile mind and the adult mind among\nourselves. In the child we see absorption in special facts. Generalities\neven of a low order are scarcely recognized, and there is no recognition\nof high generalities. We see interest in individuals, in personal\nadventures, in domestic affairs, but no interest in political or social\nmatters. We see vanity about clothes and small achievements, but little\nsense of justice: witness the forcible appropriation of one another's\ntoys. While there have come into play many of the simpler mental powers,\nthere has not yet been reached that complication of mind which results\nfrom the addition of powers evolved out of these simpler ones. Kindred\ndifferences of complexity exist between the minds of lower and higher\nraces; and comparisons should be made to ascertain their kinds and\namounts. Here, too, there may be a subdivision of the inquiries. (_a_)\nWhat is the relation between mental complexity and mental mass? Do not\nthe two habitually vary together? (_b_) What is the relation to the\nsocial state, as more or less complex? that is to say--Do not mental\ncomplexity and social complexity act and react on each other?\n\n3. _Rate of mental development._--In conformity with the biological law\nthat the higher the organisms the longer they take to evolve, members of\nthe inferior human races may be expected to complete their mental\nevolution sooner than members of the superior races; and we have\nevidence that they do this. Travellers from many regions comment, now on\nthe great precocity of children among savage and semi-civilized peoples,\nand now on the early arrest of their mental progress. Though we scarcely\nneed more proofs that this general contrast exists, there remains to be\nasked the question, whether it is consistently maintained throughout all\ngroups of races, from the lowest to the highest--whether, say, the\nAustralian differs in this respect from the Hindu, as much as the Hindu\ndoes from the European. Of secondary inquiries coming under this\nsub-head may be named several. (_a_) Is this more rapid evolution and\nearlier arrest always unequally shown by the two sexes; or, in other\nwords, are there in lower types proportional differences in rate and\ndegree of development, such as higher types show us? (_b_) Is there in\nmany cases, as there appears to be in some cases, a traceable relation\nbetween the period of arrest and the period of puberty? (_c_) Is mental\ndecay early in proportion as mental evolution is rapid? (_d_) Can we in\nother respects assert that where the type is low, the entire cycle of\nmental changes between birth and death--ascending, uniform,\ndescending--comes within a shorter interval?\n\n4. _Relative plasticity._--Is there any relation between the degree of\nmental modifiability which remains in adult life, and the character of\nthe mental evolution in respect of mass, complexity, and rapidity? The\nanimal kingdom at large yields reasons for associating an inferior and\nmore rapidly-completed mental structure, with a relatively automatic\nnature. Lowly organized creatures, guided almost entirely by reflex\nactions, are in but small degrees changeable by individual experiences.\nAs the nervous structure complicates, its actions become less rigorously\nconfined within pre-established limits; and as we approach the highest\ncreatures, individual experiences take larger and larger shares in\nmoulding the conduct: there is an increasing ability to take in new\nimpressions and to profit by the acquisitions. Inferior and superior\nhuman races are contrasted in this respect. Many travellers comment on\nthe unchangeable habits of savages. The semi-civilized nations of the\nEast, past and present, were, or are, characterized by a greater\nrigidity of custom than characterizes the more civilized nations of the\nWest. The histories of the most civilized nations show us that in their\nearlier times, the modifiability of ideas and habits was less than it is\nat present. And if we contrast classes or individuals around us, we see\nthat the most developed in mind are the most plastic. To inquiries\nrespecting this trait of comparative plasticity, in its relations to\nprecocity and early completion of mental development, may fitly be added\ninquiries respecting its relations to the social state, which it helps\nto determine, and which reacts upon it.\n\n5. _Variability._--To say of a mind that its actions are extremely\ninconstant, and at the same time to say that it is of relatively\nunchangeable nature, apparently implies a contradiction. When, however,\nthe inconstancy is understood as referring to the manifestations which\nfollow one another from minute to minute, and the unchangeableness to\nthe average manifestations, extending over long periods, the apparent\ncontradiction disappears; and it becomes comprehensible that the two\ntraits may, and ordinarily do, co-exist. An infant, quickly wearied with\neach kind of perception, wanting ever a new object which it soon\nabandons for something else, and alternating a score times a day between\nsmiles and tears, shows us a very small persistence in each kind of\nmental action: all its states, intellectual and emotional, are\ntransient. Yet at the same time its mind cannot be easily changed in\ncharacter. True, it changes spontaneously in due course; but it long\nremains incapable of receiving ideas or emotions beyond those of simple\norders. The child exhibits less rapid variations, intellectual and\nemotional, while its educability is greater. Inferior human races show\nus this combination: great rigidity of general character with great\nirregularity in its passing manifestations. Speaking broadly, while they\nresist permanent modification, they lack intellectual persistence, and\nthey lack emotional persistence. Of various low types we read that they\ncannot keep the attention fixed beyond a few minutes on anything\nrequiring thought, even of a simple kind. Similarly with their feelings:\nthese are less enduring than those of civilized men. There are, however,\nqualifications to be made in this statement; and comparisons are needed\nto ascertain how far these qualifications go. The savage shows great\npersistence in the action of the lower intellectual faculties. He is\nuntiring in minute observation. He is untiring, also, in that kind of\nperceptive activity which accompanies the making of his weapons and\nornaments: often persevering for immense periods in carving stones, &c.\nEmotionally, too, he shows persistence not only in the motives prompting\nthese small industries, but also in certain of his passions--especially\nin that of revenge. Hence, in studying the degrees of mental variability\nshown us in the daily lives of the different races, we must ask how far\nvariability characterizes the whole mind, and how far it holds only of\nparts of the mind.\n\n6. _Impulsiveness._--This trait is closely allied with the last:\nunenduring emotions are emotions which sway the conduct now this way and\nnow that, without any consistency. The trait of impulsiveness may,\nhowever, be fitly dealt with separately, because it has other\nimplications than mere lack of persistence. Comparisons of the lower\nhuman races with the higher, appear generally to show that, along with\nbrevity of the passions, there goes violence. The sudden gusts of\nfeeling which men of inferior types display, are excessive in degree as\nthey are short in duration; and there is probably a connexion between\nthese two traits: intensity sooner producing exhaustion. Observing that\nthe passions of childhood illustrate this connexion, let us turn to\ncertain interesting questions concerning the decrease of impulsiveness\nwhich accompanies advance in evolution. The nervous processes of an\nimpulsive being, are less remote from reflex actions than are those of\nan unimpulsive being. In reflex actions we see a simple stimulus passing\nsuddenly into movement: little or no control being exercised by other\nparts of the nervous system. As we ascend to higher actions, guided by\nmore and more complicated combinations of stimuli, there is not the same\ninstantaneous discharge in simple motions; but there is a comparatively\ndeliberate and more variable adjustment of compound motions, duly\nrestrained and proportioned. It is thus with the passions and sentiments\nin the less developed natures and in the more developed natures. Where\nthere is but little emotional complexity, an emotion, when excited by\nsome occurrence, explodes in action before the other emotions have been\ncalled into play; and each of these, from time to time, does the like.\nBut the more complex emotional structure is one in which these simpler\nemotions are so co-ordinated that they do not act independently. Before\nexcitement of any one has had time to cause action, some excitement has\nbeen communicated to others--often antagonistic ones; and the conduct\nbecomes modified in adjustment to the combined dictates. Hence results a\ndecreased impulsiveness, and also a greater persistence. The conduct\npursued, being prompted by several emotions co-operating in degrees\nwhich do not exhaust them, acquires a greater continuity; and while\nspasmodic force becomes less conspicuous, there is an increase in the\ntotal energy. Examining the facts from this point of view, there are\nsundry questions of interest to be put respecting the different races of\nmen. (_a_) To what other traits than degree of mental evolution is\nimpulsiveness related? Apart from difference in elevation of type, the\nNew-World races seem to be less impulsive than the Old-World races. Is\nthis due to constitutional apathy? Can there be traced (other things\nequal) a relation between physical vivacity and mental impulsiveness?\n(_b_) What connexion is there between this trait and the social state?\nClearly a very explosive nature--such as that of the Bushman--is unfit\nfor social union; and, commonly, social union, when by any means\nestablished, checks impulsiveness. (_c_) What respective shares in\nchecking impulsiveness are taken by the feelings which the social state\nfosters--such as the fear of surrounding individuals, the instinct of\nsociality, the desire to accumulate property, the sympathetic feelings,\nthe sentiment of justice? These, which require a social environment for\ntheir development, all of them involve imaginations of consequences more\nor less distant; and thus imply checks upon the promptings of the\nsimpler passions. Hence arise the questions--In what order, in what\ndegrees, and in what combinations, do they come into play?\n\n7. One further general inquiry of a different kind may be added. What\neffect is produced on mental nature by mixture of races? There is reason\nfor believing that throughout the animal kingdom, the union of varieties\nwhich have become widely divergent is physically injurious; while the\nunion of slightly divergent varieties is physically beneficial. Does the\nlike hold with the mental nature? Some facts seem to show that mixture\nof human races extremely unlike, produces a worthless type of mind--a\nmind fitted neither for the kind of life led by the higher of the two\nraces, nor for that led by the lower--a mind out of adjustment to all\nconditions of life. Contrariwise, we find that peoples of the same\nstock, slightly differentiated by lives carried on in unlike\ncircumstances for many generations, produce by mixture a mental type\nhaving certain superiorities. In his work on _The Huguenots_, Mr. Smiles\npoints out how large a number of distinguished men among us have\ndescended from Flemish and French refugees; and M. Alphonse de Candolle,\nin his _Histoire des Sciences et des Savants depuis deux Siecles_, shows\nthat the descendants of French refugees in Switzerland have produced an\nunusually great proportion of scientific men. Though, in part, this\nresult may be ascribed to the original natures of such refugees, who\nmust have had that independence which is a chief factor in originality,\nyet it is probably in part due to mixtures of races. For thinking this,\nwe have evidence which is not open to two interpretations. Prof. Morley\ndraws attention to the fact that, during seven hundred years of our\nearly history \"the best genius of England sprang up on the line of\ncountry in which Celts and Anglo-Saxons came together.\" In like manner\nMr. Galton, in his _English Men of Science_, shows that in recent days\nthese have mostly come from an inland region, running generally from\nnorth to south, which we may reasonably presume contains more mixed\nblood than do the regions east and west of it. Such a result seems\nprobable _a priori_. Two natures respectively adapted to slightly unlike\nsets of social conditions, may be expected by their union to produce a\nnature somewhat more plastic than either--a nature more impressible by\nthe new circumstances of advancing social life, and therefore more\nlikely to originate new ideas and display modified sentiments. The\nComparative Psychology of Man may, then, fitly include the mental\neffects of mixture; and among derivative inquiries we may ask--How far\nthe conquest of race by race has been instrumental in advancing\ncivilization by aiding mixture, as well as in other ways.\n\n\nII.--The second of the three leading divisions named at the outset is\nless extensive. Still, concerning the relative mental natures of the\nsexes in each race, questions of much interest and importance may be\nraised.\n\n1. _Degree of difference between the sexes._--It is an established fact\nthat, physically considered, the contrast between males and females is\nnot equally great in all types of mankind. The bearded races, for\ninstance, show us a greater unlikeness between the two than do the\nbeardless races. Among South American tribes, men and women have a\ngreater general resemblance in form, &c., than is usual elsewhere. The\nquestion, then, suggests itself--Do the mental natures of the sexes\ndiffer in a constant or in a variable degree? The difference is unlikely\nto be a constant one; and, looking for variation, we may ask what is its\namount, and under what conditions does it occur?\n\n2. _Difference in mass and in complexity._--The comparisons between the\nsexes, of course, admit of subdivisions parallel to those made in the\ncomparisons between races. Relative mental mass and relative mental\ncomplexity have chiefly to be observed. Assuming that the great\ninequality in the cost of reproduction to the two sexes, is the cause of\nunlikeness in mental mass, as in physical mass, this difference may be\nstudied in connexion with reproductive differences presented by the\nvarious races, in respect of the ages at which reproduction commences,\nand the periods over which it lasts. An allied inquiry may be joined\nwith this; namely, how far the mental developments of the two sexes are\naffected by their relative habits in respect to food and physical\nexertion? In many of the lower races, the women, treated with great\nbrutality, are, physically, much inferior to the men: excess of labour\nand defect of nutrition being apparently the combined causes. Is any\narrest of mental development simultaneously caused?\n\n3. _Variation of the differences._--If the unlikeness, physical and\nmental, of the sexes is not constant, then, supposing all races have\ndiverged from one original stock, it follows that there must have been\ntransmission of accumulated differences to those of the same sex in\nposterity. If, for instance, the prehistoric type of man was beardless,\nthen the production of a bearded variety implies that within that\nvariety the males continued to transmit an increasing amount of beard to\ndescendants of the same sex. This limitation of heredity by sex, shown\nus in multitudinous ways throughout the animal kingdom, probably applies\nto the cerebral structures as much as to other structures. Hence the\nquestion--Do not the mental natures of the sexes in alien types of Man\ndiverge in unlike ways and degrees?\n\n4. _Causes of the differences._--Are any relations to be traced between\nthese variable differences and the variable parts the sexes play in the\nbusiness of life? Assuming the cumulative effects of habit on function\nand structure, as well as the limitation of heredity by sex, it is to be\nexpected that if, in any society, the activities of one sex, generation\nafter generation, differ from those of the other, there will arise\nsexual adaptations of mind. Some instances in illustration may be named.\nAmong the Africans of Loango and other districts, as also among some of\nthe Indian Hill-tribes, the men and women are strongly contrasted as\nrespectively inert and energetic: the industry of the women having\napparently become so natural to them that no coercion is needed. Of\ncourse, such facts suggest an extensive series of questions. Limitation\nof heredity by sex may account both for those sexual differences of mind\nwhich distinguish men and women in all races, and for those which\ndistinguish them in each race, or each society. An interesting\nsubordinate inquiry may be, how far such mental differences are inverted\nin cases where there is inversion of social and domestic relations; as\namong those Khasi Hill-tribes, whose women have so far the upper hand\nthat they turn off their husbands in a summary way if they displease\nthem.\n\n5. _Mental modifiability in the two sexes._--Along with comparisons of\nraces in respect of mental plasticity may go parallel comparisons of the\nsexes in each race. Is it true always, as it appears to be generally\ntrue, that women are less modifiable than men? The relative conservatism\nof women--their greater adhesion to established ideas and practices--is\nmanifest in many civilized and semi-civilized societies. Is it so among\nthe uncivilized? A curious instance of stronger attachment to custom in\nwomen than in men is given by Dalton, as occurring among the Juangs, one\nof the lowest wild tribes of Bengal. Until recently the only dress of\nboth sexes was something less than that which the Hebrew legend gives to\nAdam and Eve. Years ago the men were led to adopt a cloth bandage round\nthe loins, in place of the bunch of leaves; but the women adhered to the\naboriginal habit: a conservatism shown where it might have been least\nexpected.\n\n6. _The sexual sentiment._--Results of value may be looked for from\ncomparisons of races made to determine the amounts and characters of the\nhigher feelings to which the relation of the sexes gives rise. The\nlowest varieties of mankind have but small endowments of these feelings.\nAmong varieties of higher types, such as the Malayo-Polynesians, these\nfeelings seem considerably developed: the Dyaks, for instance, sometimes\ndisplay them in great strength. Speaking generally, they appear to\nbecome stronger with the advance of civilization. Several subordinate\ninquiries may be named. (_a_) How far is development of the sexual\nsentiment dependent upon intellectual advance--upon growth of\nimaginative power? (_b_) How far is it related to emotional advance; and\nespecially to evolution of those emotions which originate from sympathy?\nWhat are its relations to polyandry and polygyny? (_c_) Does it not\ntend towards, and is it not fostered by, monogamy? (_d_) What connexion\nhas it with maintenance of the family bond, and the consequent better\nrearing of children?\n\n\nIII.--Under the third head, to which we may now pass come the more\nspecial traits of the different races.\n\n1. _Imitativeness._--One of the characteristics in which the lower types\nof men show us a smaller departure from reflex action than do the higher\ntypes, is their strong tendency to mimic the motions and sounds made by\nothers--an almost involuntary habit which travellers find it difficult\nto check. This meaningless repetition, which seems to imply that the\nidea of an observed action cannot be framed in the mind of the observer\nwithout tending forthwith to discharge itself in the action conceived\n(and every ideal action is a nascent form of the consciousness\naccompanying performance of such action), evidently diverges but little\nfrom the automatic; and decrease of it is to be expected along with\nincrease of self-regulating power. This trait of automatic mimicry is\nevidently allied with that less automatic mimicry which shows itself in\ngreater persistence of customs. For customs adopted by each generation\nfrom the last without thought or inquiry, imply a tendency to imitate\nwhich overmasters critical and sceptical tendencies: so maintaining\nhabits for which no reasons can be given. The decrease of this\nirrational mimicry, strongest in the lowest savage and feeblest in the\nhighest of the civilized, should be studied along with the successively\nhigher stages of social life, as being at once an aid and a hindrance to\ncivilization: an aid in so far as it gives that fixity to the social\norganization without which a society cannot survive; a hindrance in so\nfar as it offers resistance to changes of social organization that have\nbecome desirable.\n\n2. _Incuriosity._--Projecting our own natures into the circumstances of\nthe savage, we imagine ourselves as marvelling greatly on first seeing\nthe products and appliances of civilized life. But we err in supposing\nthat the savage has feelings such as we should have in his place. Want\nof rational curiosity respecting these incomprehensible novelties, is a\ntrait remarked of the lowest races wherever found; and the\npartially-civilized races are distinguished from them as exhibiting\nrational curiosity. The relation of this trait to the intellectual\nnature, to the emotional nature, and to the social state, should be\nstudied.\n\n3. _Quality of thought._--Under this vague head may be placed many sets\nof inquiries, each of them extensive--(_a_) The degree of generality of\nthe ideas; (_b_) the degree of abstractness of the ideas; (_c_) the\ndegree of definiteness of the ideas; (_d_) the degree of coherence of\nthe ideas; (_e_) the extent to which there have been developed such\nnotions as those of _class_, of _cause_, of _uniformity_, of _law_, of\n_truth_. Many conceptions which have become so familiar to us that we\nassume them to be the common property of all minds, are no more\npossessed by the lowest savages than they are by our own children; and\ncomparisons of types should be so made as to elucidate the processes by\nwhich such conceptions are reached. The development under each head has\nto be observed--(_a_) independently in its successive stages; (_b_) in\nconnexion with the co-operative intellectual conceptions; (_c_) in\nconnexion with the progress of language, of the arts, and of social\norganization. Already linguistic phenomena have been used in aid of such\ninquiries; and more systematic use of them should be made. Not only the\nnumber of general words, and the number of abstract words, in a people's\nvocabulary should be taken as evidence, but also their _degrees_ of\ngenerality and abstractness; for there are generalities of the first,\nsecond, third, &c., orders, and abstractions similarly ascending. _Blue_\nis an abstraction referring to one class of impressions derived from\nvisible objects; _colour_ is a higher abstraction referring to many such\nclasses of visual impressions; _property_ is a still higher\nabstraction referring to classes of impressions received not through the\neyes alone, but through other sense-organs. If generalities and\nabstractions were arranged in the order of their extensiveness and in\nthe order of their grades, tests would be obtained which, applied to the\nvocabularies of the uncivilized, would yield definite evidence of the\nintellectual stages reached.\n\n4. _Peculiar aptitudes._--To such specialities of intelligence as mark\ndifferent degrees of evolution, have to be added minor ones related to\nmodes of life: the kinds and degrees of faculty which have become\norganized in adaptation to daily habits--skill in the use of weapons,\npowers of tracking, quick discrimination of individual objects. And\nunder this head may fitly come inquiries concerning some\nrace-peculiarities of the aesthetic class, not at present explicable.\nWhile the remains from the Dordogne caves show us that their\ninhabitants, low as we must suppose them to have been, could represent\nanimals, both by drawing and carving, with some degree of fidelity;\nthere are existing races, probably higher in other respects, who seem\nscarcely capable of recognizing pictorial representations. Similarly\nwith the musical faculty. Almost or quite wanting in some inferior\nraces, we find it in other races not of high grade, developed to an\nunexpected degree: instance the Negroes, some of whom are so innately\nmusical, that, as I have been told by a missionary among them, the\nchildren in native schools when taught European psalm-tunes,\nspontaneously sing seconds to them. Whether any causes can be discovered\nfor race peculiarities of this kind, is a question of interest.\n\n5. _Specialities of emotional nature._--These are worthy of careful\nstudy, as being intimately related to social phenomena--to the\npossibility of social progress, and to the nature of the social\nstructure. Among others to be noted there are--(_a_) Gregariousness or\nsociality--a trait in the strength of which races differ widely: some,\nas the Mantras, being almost indifferent to social intercourse; some\nbeing unable to dispense with it. Obviously the degree of this desire\nfor the presence of fellow-men, affects greatly the formation of social\ngroups, and consequently influences social progress. (_b_) Intolerance\nof restraint. Men of some inferior types, as the Mapuche, are\nungovernable; while those of other types, no higher in grade, not only\nsubmit to restraint, but admire the persons exercising it. These\ncontrasted natures have to be observed in connexion with social\nevolution; to the early stages of which they are respectively\nantagonistic and favourable. (_c_) The desire for praise is a trait\nwhich, common to all races, high and low, varies considerably in degree.\nThere are quite inferior races, as some of those in the Pacific States,\nwhose members sacrifice without stint to gain the applause which lavish\ngenerosity brings; while, elsewhere, applause is sought with less\neagerness. Notice should be taken of the connexion between this love of\napprobation and the social restraints; since it plays an important part\nin the maintenance of them. (_d_) The acquisitive propensity. This, too,\nis a character the degrees of which, and the relations of which to the\nsocial state, have to be especially noted. The desire for property grows\nalong with the possibility of gratifying it; and this, extremely small\namong the lowest men, increases as social development goes on. With the\nadvance from tribal property to family property and individual property,\nthe notion of private right of possession gains definiteness, and the\nlove of acquisition strengthens. Each step towards an orderly social\nstate makes larger accumulations possible, and the pleasures achievable\nby them more sure; while the resulting encouragement to accumulate,\nleads to increase of capital and to further progress. This action and\nre-action of the sentiment and the social state, should be in every case\nobserved.\n\n6. _The altruistic sentiments._--Coming last, these are also highest.\nThe evolution of them in the course of civilization, shows us clearly\nthe reciprocal influences of the social unit and the social organism. On\nthe one hand, there can be no sympathy, nor any of the sentiments which\nsympathy generates, unless there are fellow-beings around. On the other\nhand, maintenance of union with fellow-beings depends in part on the\npresence of sympathy, and the resulting restraints on conduct.\nGregariousness or sociality favours the growth of sympathy; increased\nsympathy conduces to closer sociality and a more stable social state;\nand so, continuously, each increment of the one makes possible a further\nincrement of the other. Comparisons of the altruistic sentiments\nresulting from sympathy, as exhibited in different types of men and\ndifferent social states, may be conveniently arranged under three\nheads--(_a_) Pity, which should be observed as displayed towards\noffspring, towards the sick and aged, and towards enemies. (_b_)\nGenerosity (duly discriminated from the love of display) as shown in\ngiving; as shown in the relinquishment of pleasures for the sake of\nothers; as shown by active efforts on others' behalf. The manifestations\nof this sentiment, too, are to be noted in respect of their\nrange--whether they are limited to relatives; whether they extend only\nto those of the same society; whether they extend to those of other\nsocieties; and they are also to be noted in connexion with the degree of\nprovidence--whether they result from sudden impulses obeyed without\ncounting the cost, or go along with clear foresight of the future\nsacrifices entailed. (_c_) Justice. This most abstract of the altruistic\nsentiments is to be considered under aspects like those just named, as\nwell as under many other aspects--how far it is shown in regard to the\nlives of others; how far in regard to their freedom; how far in regard\nto their property; how far in regard to their various minor claims. And\ncomparisons concerning this highest sentiment should, beyond all others,\nbe carried on along with comparisons of the accompanying social\nstates, which it largely determines--the forms and actions of\ngovernments; the characters of laws; the relations of classes.\n\n       *       *       *       *       *\n\nSuch, stated as briefly as consists with clearness, are the leading\ndivisions and subdivisions under which the Comparative Psychology of Man\nmay be arranged. In going rapidly over so wide a field, I have doubtless\noverlooked much that should be included. Doubtless, too, various of the\ninquiries named will branch out into subordinate inquiries well worth\npursuing. Even as it is, however, the programme is extensive enough to\noccupy numerous investigators, who may with advantage take separate\ndivisions.\n\nThough, after occupying themselves with primitive arts and products,\nanthropologists have devoted their attention mainly to the physical\ncharacters of the human races; it must, I think, be admitted that the\nstudy of these yields in importance to the study of their psychical\ncharacters. The general conclusions to which the first set of inquiries\nmay lead, cannot so much affect our views respecting the highest classes\nof phenomena as can the general conclusions to which the second set may\nlead. A true theory of the human mind vitally concerns us; and\nsystematic comparisons of human minds, differing in their kinds and\ngrades, will help us in forming a true theory. Knowledge of the\nreciprocal relations between the characters of men and the characters of\nthe societies they form, must influence profoundly our ideas of\npolitical arrangements. When the inter-dependence of individual natures\nand social structures is understood, our conceptions of the changes now\ntaking place, and hereafter to take place, will be rectified. A\ncomprehension of mental development as a process of adaptation to social\nconditions, which are continually remoulding the mind and are again\nremoulded by it, will conduce to a salutary consciousness of the\nremoter effects produced by institutions upon character; and will\ncheck the grave mischiefs which ignorant legislation now causes. Lastly,\na right theory of mental evolution as exhibited by humanity at large,\ngiving a key, as it does, to the evolution of the individual mind, must\nhelp to rationalize our perverse methods of education; and so to raise\nintellectual power and moral nature.\n\n\n\n\nMR. MARTINEAU ON EVOLUTION.\n\n    [_First published in _The Contemporary Review_, for June,_ 1872.]\n\n\nThe article by Mr. Martineau, in the April number of the _Contemporary\nReview_, on \"The Place of Mind in Nature, and Intuition of Man,\"\nrecalled to me a partially-formed intention to deal with the chief\ncriticisms which have from time to time been made on the general\ndoctrine set forth in _First Principles_; since, though not avowedly\ndirected against propositions asserted or implied in that work, Mr.\nMartineau's reasoning tells against them by implication. The fulfilment\nof this intention I should, however, have continued to postpone, had I\nnot learned that the arguments of Mr. Martineau are supposed by many to\nbe conclusive, and that, in the absence of replies, it will be assumed\nthat no replies can be made. It seems desirable, therefore, to notice\nthese arguments at once--especially as the essential ones may, I think,\nbe effectually dealt with in a comparatively small space.\n\n       *       *       *       *       *\n\nThe first definite objection which Mr. Martineau raises is, that the\nhypothesis of General Evolution is powerless to account even for the\nsimpler orders of facts in the absence of numerous different substances.\nHe argues that were matter all of one kind, no such phenomena as\nchemical changes would be possible; and that, \"in order to start the\nworld on its chemical career, you must enlarge its capital and present\nit with an outfit of _heterogeneous_ constituents. Try, therefore, the\neffect of such a gift; fling into the pre-existing cauldron the whole\nlist of recognized elementary substances, and give leave to their\naffinities to work.\" The intended implication obviously is, that there\nmust exist the separately-created elements before evolution can begin.\n\nHere, however, Mr. Martineau makes an assumption which few, if any,\nchemists will commit themselves to, and which many will distinctly deny.\nThere are no \"recognized elementary substances,\" if the expression means\nsubstances known to be elementary. What chemists, for convenience, call\nelementary substances, are merely substances which they have thus far\nfailed to decompose; but, bearing in mind past experiences, they do not\ndare to say that they are absolutely undecomposable. Water was taken to\nbe an element for more than two thousand years, and then was proved to\nbe a compound; and, until Davy brought a galvanic current to bear upon\nthem, the alkalies and the earths were supposed to be elements. So\nlittle true is it that \"recognized elementary substances\" are supposed\nto be absolutely elementary, that there has been much speculation among\nchemists respecting the process of compounding and recompounding by\nwhich they have been formed out of some ultimate substance--some\nchemists having supposed the atom of hydrogen to be the unit of\ncomposition, but others having contended that the atomic weights of the\nso-called elements are not thus interpretable. If I remember rightly,\nSir John Herschel was one, among others, who, some five-and-twenty years\nago, threw out suggestions respecting a system of compounding that might\nexplain these relations of the atomic weights.\n\nWhat was at that time a suspicion has now become practically a\ncertainty. Spectrum-analysis yields results wholly irreconcilable with\nthe assumption that the conventionally-named simple substances are\nreally simple. Each yields a spectrum having lines varying in number\nfrom two to eighty or more, every one of which implies the intercepting\nof ethereal undulations of a certain order by something oscillating in\nunison or in harmony with them. Were iron absolutely elementary, it is\nnot conceivable that its atom could intercept ethereal undulations of\neighty different orders. Though it does not follow that its molecule\ncontains as many separate atoms as there are lines in its spectrum, it\nmust clearly be a complex molecule. The evidence thus gained points to\nthe conclusion that, out of some primordial units, the so-called\nelements arise by compounding and recompounding; just as by the\ncompounding and recompounding of so-called elements there arise oxides,\nand acids, and salts.\n\nAnd this hypothesis is entirely in harmony with the phenomena of\nallotropy. Various substances, conventionally distinguished as simple,\nhave several forms under which they present quite different properties.\nThe semi-transparent, colourless, extremely active substance called\nphosphorus may be so changed as to become opaque, dark red, and inert.\nLike changes are known to occur in some gaseous, non-metallic elements,\nas oxygen; and also in metallic elements, as antimony. These total\nchanges of properties, brought about without any changes to be called\nchemical, are interpretable only as due to molecular rearrangements;\nand, by showing that difference of property is producible by difference\nof arrangement, they support the inference otherwise to be drawn, that\nthe properties of different elements result from differences of\narrangement arising by the compounding and recompounding of ultimate\nhomogeneous units.\n\nThus Mr. Martineau's objection, which at best would imply a turning of\nour ignorance of the nature of elements into positive knowledge that\nthey are simple, is, in fact, to be met by two sets of evidences, which\nimply that they are compound.\n\n       *       *       *       *       *\n\nMr. Martineau next alleges that a fatal difficulty is put in the way of\nthe General Doctrine of Evolution by the existence of a chasm between\nthe living and the not-living. He says:--\"But with all your enlargement\nof data, turn them as you will, at the end of every passage which they\nexplore, the _door of life_ is closed against them still.\" Here again\nour ignorance is employed to play the part of knowledge. The fact that\nwe do not know distinctly how an alleged transition has taken place, is\ntransformed into the assumption that no transition has taken place. We\nhave, in a more general shape, the argument which until lately was\nthought conclusive--the argument that because the genesis of each\nspecies of creature had not been explained, therefore each species must\nhave been separately created.\n\nMerely noting this, however, I go on to remark that scientific discovery\nis day by day narrowing the chasm, or, to vary Mr. Martineau's metaphor,\n\"opening the door.\" Not many years since, it was held as certain that\nthe chemical compounds distinguished as organic could not be formed\nartificially. Now, more than a thousand organic compounds have been\nformed artificially. Chemists have discovered the art of building them\nup from the simpler to the more complex, and do not doubt that they will\neventually produce the most complex. Moreover, the phenomena attending\nisomeric change give a clue to those movements which are the only\nindications we have of life in its lowest forms. In various colloidal\nsubstances, including the albuminoid, isomeric change is accompanied by\ncontraction or expansion, and consequent motion; and, in such primordial\ntypes as the _Protogenes_ of Haeckel, which do not differ in appearance\nfrom minute portions of albumen, the observed motions are comprehensible\nas accompanying isomeric changes caused by variations in surrounding\nphysical actions. The probability of this interpretation will be seen on\nremembering the evidence we have that, in the higher organisms, many\nfunctions are essentially effected by isomeric changes from one to\nanother of the multitudinous forms which protein assumes.\n\nThus the reply to this objection is, first, that there is going on from\nboth sides a narrowing of the chasm supposed to be impassable; and,\nsecondly, that, even were the chasm not in course of being filled up, we\nshould no more be justified in therefore assuming a supernatural\ncommencement of life, than Kepler was justified in assuming that there\nwere guiding-spirits to keep the planets in their orbits, because he\ncould not see how else they were to be kept in their orbits.\n\n       *       *       *       *       *\n\nThe third definite objection made by Mr. Martineau is of kindred nature.\nThe Hypothesis of Evolution is, he thinks, met by the insurmountable\ndifficulty that plant life and animal life are absolutely distinct. \"You\ncannot,\" he says, \"take a single step toward the deduction of sensation\nand thought: neither at the upper limit do the highest plants (the\nexogens) transcend themselves and overbalance into animal existence; nor\nat the lower, grope as you may among the sea-weeds and sponges, can you\npersuade the sporules of the one to develop into the other.\"\n\nThis is an extremely unfortunate objection to raise. For, though there\nare no transitions from vegetal to animal life at the places Mr.\nMartineau names, where, indeed, no biologist would look for them; yet\nthe connexion between the two great kingdoms of living things is so\ncomplete that separation is now regarded as impossible. For a long time\nnaturalists endeavored to frame definitions such as would, the one\ninclude all plants and exclude all animals, and the other include all\nanimals and exclude all plants. But they have been so repeatedly foiled\nin the attempt that they have given it up. There is no chemical\ndistinction which holds; there is no structural distinction which\nholds; there is no functional distinction which holds; there is no\ndistinction as to mode of existence which holds. Large groups of the\nsimpler animals contain chlorophyll, and decompose carbonic acid under\nthe influence of light, as plants do. Large groups of the simpler\nplants, as you may observe in the diatoms from any stagnant pool, are no\nless actively locomotive than the minute creatures classed as animals\nseen along with them. Nay, among these lowest types of living things, it\nis common for the life to be now predominantly animal and presently to\nbecome predominantly vegetal. The very name _zoospores_, given to germs\nof _algae_, which for a while swim about actively by means of cilia, and\npresently settling down grow into plant-forms, is given because of this\nconspicuous community of nature. So complete is this community of nature\nthat for some time past many naturalists have wished to establish for\nthese lowest types a sub-kingdom, intermediate between the animal and\nthe vegetal: the reason against this course being, however, that the\ndifficulty crops up afresh at any assumed places where this intermediate\nsub-kingdom may be supposed to join the other two.\n\nThus the assumption on which Mr. Martineau proceeds is diametrically\nopposed to the conviction of naturalists in general.\n\n       *       *       *       *       *\n\nThough I do not perceive that it is specifically stated, there appears\nto be tacitly implied a fourth difficulty of allied kind--the difficulty\nthat there is no possibility of transition from life of the simplest\nkind to mind. Mr. Martineau says, indeed, that there can be \"with only\nvital resources, as in the vegetable world, no beginning of mind:\"\napparently leaving it to be inferred that in the animal world the\nresources are such as to make the \"beginning of mind\" comprehensible.\nIf, however, instead of leaving it a latent inference, he had\ndistinctly asserted a chasm between mind and bodily life, for which\nthere is certainly quite as much reason as for asserting a chasm between\nanimal life and vegetal life, the difficulties in his way would have\nbeen no less insuperable.\n\nFor those lowest forms of irritability in the animal kingdom which, I\nsuppose, Mr. Martineau refers to as the \"beginning of mind,\" are not\ndistinguishable from the irritability which plants display: they in no\ngreater degree imply consciousness. If the sudden folding of a\nsensitive-plant's leaf when touched, or the spreading out of the stamens\nin a wild-cistus when gently brushed, is to be considered a vital action\nof a purely physical kind; then so too must be considered the equally\nslow contraction of a polype's tentacles. And yet, from this simple\nmotion of an animal of low type, we may pass by insensible stages\nthrough ever-complicating forms of actions, with their accompanying\nsigns of feeling and intelligence, until we reach the highest.\n\nEven apart from the evidence derived from the ascending grades of\nanimals up from _zoophytes_, as they are significantly named, it needs\nonly to observe the evolution of a single animal to see that there does\nnot exist any break or chasm between the life which shows no mind and\nthe life which shows mind. The yelk of an egg which the cook has just\nbroken, not only yields no sign of mind, but yields no sign of life. It\ndoes not respond to a stimulus as much even as many plants do. Had the\negg, instead of being broken by the cook, been left under the hen for a\ncertain time, the yelk would have passed by infinitesimal gradations\nthrough a series of forms ending in the chick; and by similarly\ninfinitesimal gradations would have arisen those functions which end in\nthe chick breaking its shell; and which, when it gets out, show\nthemselves in running about, distinguishing and picking up food, and\nsqueaking if hurt. When did the feeling begin? and how did there come\ninto existence that power of perception which the chick's actions show?\nShould it be objected that the chick's actions are mainly automatic, I\nwill not dwell on the fact that, though they are largely so, the chick\nmanifestly has feeling and therefore consciousness; but I will accept\nthe objection, and propose that instead we take the human being. The\ncourse of development before birth is just of the same general kind; and\nsimilarly, at a certain stage, begins to be accompanied by reflex\nmovements. At birth there is displayed an amount of mind certainly not\ngreater than that of the chick: there is no power of running from\ndanger--no power of distinguishing and picking up food. If we say the\nchick is unintelligent, we must certainly say the infant is\nunintelligent. And yet from the unintelligence of the infant to the\nintelligence of the adult, there is an advance by steps so small that on\nno day is the amount of mind shown, appreciably different from that\nshown on preceding and succeeding days.\n\nThus the tacit assumption that there exists a break, is not simply\ngratuitous, but is negatived by the most obvious facts.\n\n       *       *       *       *       *\n\nCertain of the words and phrases used in explaining that particular part\nof the Doctrine of Evolution which deals with the origin of species, are\ncommented upon by Mr. Martineau as having implications justifying his\nview. Let us consider his comments.\n\nHe says that _competition_ is not an \"original power, which can of\nitself do anything;\" further, that \"it cannot act except in the presence\nof some _possibility of a better or worse_;\" and that this \"possibility\nof a better or worse\" implies a \"world pre-arranged for progress,\" \"a\ndirecting Will intent upon the good.\" Had Mr. Martineau looked more\nclosely into the matter, he would have found that, though the words and\nphrases he quotes are used for convenience, the conceptions they\nimply are not at all essential to the doctrine. Under its\nrigorously-scientific form, the doctrine is expressible in\npurely-physical terms, which neither imply competition nor imply better\nand worse.[37]\n\nBeyond this indirect mistake there is a direct mistake. Mr. Martineau\nspeaks of the \"survivorship of the better,\" as though that were the\nstatement of the law; and then adds that the alleged result cannot be\ninferred \"except on the assumption that whatever is _better_ is\n_stronger_ too.\" But the words he here uses are his own words, not the\nwords of those he opposes. The law is the survival of the _fittest_.\nProbably, in substituting \"better\" for \"fittest,\" Mr. Martineau did not\nsuppose that he was changing the meaning; though I dare say he perceived\nthat the meaning of the word \"fittest\" did not suit his argument so\nwell. Had he examined the facts, he would have found that the law is not\nthe survival of the \"better\" or the \"stronger,\" if we give to those\nwords any thing like their ordinary meanings. It is the survival of\nthose which are constitutionally fittest to thrive under the conditions\nin which they are placed; and very often that which, humanly speaking,\nis inferiority, causes the survival. Superiority, whether in size,\nstrength, activity, or sagacity, is, other things equal, at the cost of\ndiminished fertility; and where the life led by a species does not\ndemand these higher attributes, the species profits by decrease of them,\nand accompanying increase of fertility. This is the reason why there\noccur so many cases of retrograde metamorphosis--this is the reason why\nparasites, internal and external, are so commonly degraded forms of\nhigher types. Survival of the \"better\" does not cover these cases,\nthough survival of the \"fittest\" does; and as I am responsible for the\nphrase, I suppose I am competent to say that the word \"fittest\" was\nchosen for this reason. When it is remembered that these cases outnumber\nall others--that there are more species of parasites than there are\nspecies of all other animals put together--it will be seen that the\nexpression \"survivorship of the better\" is wholly inappropriate, and the\nargument Mr. Martineau bases upon it quite untenable. Indeed, if, in\nplace of those adjustments of the human sense-organs, which he so\neloquently describes as implying pre-arrangement, Mr. Martineau had\ndescribed the countless elaborate appliances which enable parasites to\ntorture animals immeasurably superior to them, and which, from his point\nof view, no less imply pre-arrangement, I think the notes of admiration\nwhich end his descriptions would not have seemed to him so appropriate.\n\nOne more word there is from the intrinsic meaning of which Mr. Martineau\ndeduces what appears a powerful argument--the word _Evolution_ itself.\nHe says:--\n\n     \"It means, to unfold from within; and it is taken from the history\n     of the seed or embryo of living natures. And what is the seed but a\n     casket of pre-arranged futurities, with its whole contents\n     _prospective_, settled to be what they are by reference to ends\n     still in the distance?\"\n\nNow, this criticism would have been very much to the point did the word\nEvolution truly express the process it names. If this process, as\nscientifically defined, really involved that conception which the word\nevolution was originally designed to convey, the implications would be\nthose Mr. Martineau alleges. But, unfortunately for him, the word,\nhaving been in possession of the field before the process was\nunderstood, has been adopted merely because displacing it by another\nword seemed impracticable. And this adoption of it has been joined with\na caution against misunderstandings arising from its unfitness. Here is\na part of the caution:--\"Evolution has other meanings, some of which are\nincongruous with, and some even directly opposed to, the meaning here\ngiven to it.... The antithetical word, Involution, would much more truly\nexpress the nature of the process; and would, indeed, describe better\nthe secondary characters of the process which we shall have to deal\nwith presently.\"[38] So that the meanings which the word involves, and\nwhich Mr. Martineau regards as fatal to the hypothesis, are already\nrepudiated as not belonging to the hypothesis.\n\n       *       *       *       *       *\n\nAnd now, having dealt with the essential objections raised by Mr.\nMartineau to the Hypothesis of Evolution as it is presented under that\npurely scientific form which generalizes the process of things, firstly\nas observed and secondly as inferred from certain ultimate principles,\nlet me go on to examine that form of the Hypothesis which he\npropounds--Evolution as determined by Mind and Will--Evolution as\npre-arranged by a Divine Actor. For Mr. Martineau apparently abandons\nthe primitive theory of creation by \"fiat of Almighty Will\", and also\nthe theory of creation by manufacture--by \"a contriving and adapting\npower,\" and seems to believe in evolution: requiring only that \"an\noriginating Mind\" shall be taken as its antecedent. Let us ask, first,\nin what relation Mr. Martineau conceives the \"originating Mind\" to stand\nto the evolving Universe. From some passages it is inferable that he\nconsiders the \"presence of mind\" to be everywhere needful. He says:--\n\n     \"It is impossible to work the theory of Evolution upwards from the\n     bottom. If all force is to be conceived as One, its type must be\n     looked for in the highest and all-comprehending term; and Mind must\n     be conceived as there, and as divesting itself of some speciality\n     at each step of its descent to a lower stratum of law, till\n     represented at the base under the guise of simple Dynamics.\"\n\nThis seems to be an unmistakable assertion that, wherever Evolution is\ngoing on, Mind is then and there behind it. At the close of the\nargument, however, a quite different conception is implied. Mr.\nMartineau says:--\n\n    \"If the Divine Idea will not retire at the bidding of our\n    speculative science, but retains its place, it is natural to ask,\n    What is its relation to  the series of so-called Forces in the\n    world? But the question is too large and deep to be answered here.\n    Let it suffice to say, that there need not be any _overruling_ of\n    these forces by the Will of God, so that the supernatural should\n    disturb the natural; or any _supplementing_ of them, so that He\n    should fill up their deficiencies. Rather is His thought related to\n    them as, in man, the mental force is related to all below it.\"\n\nIt would take too much space to deal fully with the various questions\nwhich this last passage raises. There is the question--Whence come these\n\"Forces,\" spoken of as separate from the \"Will of God\"--did they\npre-exist? Then what becomes of the Divine Power? Do they exist by the\nDivine Will? Then what kind of nature is that by which they act apart\nfrom the Divine Will? Again, there is the question--How do these\ndeputy-forces co-operate in each particular phenomenon, if the presiding\nWill is not there present to control them? Either an organ which\ndevelops into fitness for its function, develops by the co-operation of\nthese forces under the direction of Mind then present, or it so develops\nin the absence of Mind. If it develops in the absence of Mind, the\nhypothesis is given up; and if the \"originating Mind\" is required to be\nthen and there present, we must suppose a particular providence to be\npresent in each particular organ of each particular creature throughout\nthe universe. Once more there is the question--If \"His thought is\nrelated to them [these Forces] as, in Man, the mental force is related\nto all below it,\" how can \"His thought\" be regarded as the cause of\nEvolution? In man the mental force is related to the forces below it\nneither as a creator of them nor as a regulator of them, save in a very\nlimited way: the greater part of the forces present in man, both\nstructural and functional, defy the mental force absolutely. Nay, more,\nit needs but to injure a nerve to see that the power of the mental force\nover the physical forces is dependent on conditions which are themselves\nphysical; and one who takes morphia in mistake for magnesia, discovers\nthat the power of the physical forces over the mental is\n_un_conditioned by any thing mental.\n\nNot dwelling on these questions, however, I will merely draw attention\nto the entire incongruity of this conception with the previous\nconception which I have quoted. Assuming that, when the choice is\npressed on him, Mr. Martineau will choose the first, which alone has any\nthing like defensibility, let us go on to ask how far Evolution is made\nmore comprehensible by postulating Mind, universally immanent, as its\ncause.\n\nIn metaphysical controversy, many of the propositions propounded and\naccepted as quite believable, are absolutely inconceivable. There is a\nperpetual confusing of actual ideas with what are nothing but\npseud-ideas. No distinction is made between propositions that contain\nreal thoughts, and propositions that are only the forms of thoughts. A\nthinkable proposition is one of which _the two terms can be brought\ntogether in consciousness under the relation said to exist between\nthem_. But very often, when the subject of a proposition has been\nthought of as something known, and when the predicate has been thought\nof as something known, and when the relation alleged between them has\nbeen thought of as a known relation, it is supposed that the proposition\nitself has been thought. The thinking separately of the elements of a\nproposition is mistaken for the thinking of them in the combination\nwhich the proposition affirms. And hence it continually happens that\npropositions which cannot be rendered into thought at all, are supposed\nto be not only thought but believed. The proposition that Evolution is\ncaused by Mind is one of this nature. The two terms are separately\nintelligible; but they can be regarded in the relation of effect and\ncause only so long as no attempt is made to put them together in this\nrelation.\n\nThe only thing which any one knows as Mind is the series of his own\nstates of consciousness; and if he thinks of any mind other than his\nown, he can think of it only in terms derived from his own. If I am\nasked to frame a notion of Mind divested of all those structural traits\nunder which alone I am conscious of mind in myself, I cannot do it. I\nknow nothing of thought save as carried on in ideas originally traceable\nto the effects wrought by objects and forces on me. A mental act is an\nunintelligible phrase if I am not to regard it as an act in which states\nof consciousness are severally known as like other states in the series\nthat has gone by, and in which the relations between them are severally\nknown as like past relations in the series. If, then, I have to conceive\nEvolution as caused by an \"originating Mind,\" I must conceive this Mind\nas having attributes akin to those of the only mind I know, and without\nwhich I cannot conceive Mind at all.\n\nI will not dwell on the many incongruities hence resulting, by asking\nhow the \"originating Mind\" is to be thought of as having states produced\nby things objective to it; as discriminating among these states, and\nclassing them as like and unlike; and as preferring one objective result\nto another. I will simply ask--What happens if we ascribe to the\n\"originating Mind\" the character absolutely essential to the conception\nof Mind, that it consists of a series of states of consciousness? Put a\nseries of states of consciousness as cause, and the evolving Universe as\neffect, and then endeavor to see the last as flowing from the first. I\nfind it possible to imagine in some dim way a series of states of\nconsciousness serving as antecedent to any one of the movements I see\ngoing on; for my own states of consciousness are often indirectly the\nantecedents to such movements. But how if I attempt to think of such a\nseries as antecedent to _all_ actions throughout the Universe--to the\nmotions of the multitudinous stars through space, to the revolutions of\nall their planets round them, to the gyrations of all these planets on\ntheir axes, to the infinitely-multiplied physical processes going on in\neach of these suns and planets? I cannot think of a single series of\nstates of consciousness as causing even the relatively small group of\nactions going on over the Earth's surface. I cannot think of it even as\nantecedent to all the various winds and the dissolving clouds they bear,\nto the currents of all the rivers, and the grinding actions of all the\nglaciers; still less can I think of it as antecedent to the infinity of\nprocesses simultaneously going on in all the plants that cover the\nglobe, from scattered polar lichens to crowded tropical palms, and in\nall the millions of quadrupeds that roam among them, and the millions of\nmillions of insects that buzz about them. Even to a single small set of\nthese multitudinous terrestrial changes, I cannot conceive as antecedent\na single series of states of consciousness--cannot, for instance, think\nof it as causing the hundred thousand breakers that are at this instant\ncurling over on the shores of England. How, then, is it possible for me\nto conceive an \"originating Mind,\" which I must represent to myself as a\n_single_ series of states of consciousness, working the\ninfinitely-multiplied sets of changes _simultaneously_ going on in\nworlds too numerous to count, dispersed throughout a space that baffles\nimagination?\n\nIf, to account for this infinitude of physical changes everywhere going\non, \"Mind must be conceived as there\" \"under the guise of simple\nDynamics,\" then the reply is that, to be so conceived, Mind must be\ndivested of all attributes by which it is distinguished; and that, when\nthus divested of its distinguishing attributes, the conception\ndisappears--the word Mind stands for a blank. If Mr. Martineau takes\nrefuge in the entirely different and, as it seems to me, incongruous\nhypothesis of something like a plurality of minds--if he accepts, as he\nseems to do, the doctrine that you cannot explain Evolution \"unless\namong your primordial elements you scatter already the _germs_ of Mind\nas well as the inferior elements\"--if the insuperable difficulties I\nhave just pointed out are to be met by assuming a local series of states\nof consciousness for each phenomenon, then we are obviously carried\nback to something like the alleged fetichistic notion, with the\ndifference only, that the assumed spiritual agencies are indefinitely\nmultiplied.\n\nClearly, therefore, the proposition that an \"originating Mind\" is the\ncause of Evolution, is a proposition that can be entertained so long\nonly as no attempt is made to unite in thought its two terms in the\nalleged relation. That it should be accepted as a matter of _faith_, may\nbe a defensible position, provided good cause is shown why it should be\nso accepted; but that it should be accepted as a matter of\n_understanding_--as a statement making the order of the universe\ncomprehensible--is a quite indefensible position.\n\n       *       *       *       *       *\n\nHere let me guard myself against a misinterpretation very likely to be\nput upon the foregoing arguments; especially by those who have read the\nEssay to which they reply. The statements of that Essay carry the\nimplication that all who adhere to the hypothesis it combats, imagine\nthey have solved the mystery of things when they have shown the\nprocesses of Evolution to be naturally caused. Mr. Martineau tacitly\nrepresents them as believing that, when every thing has been interpreted\nin terms of Matter and Motion, nothing remains to be explained. This,\nhowever, is by no means the fact. The Doctrine of Evolution, under its\npurely scientific form, does not involve Materialism, though its\nopponents persistently represent it as doing so. Indeed, among adherents\nof it who are friends of mine, there are those who speak of the\nMaterialism of Buechner and his school, with a contempt certainly not\nless than that felt by Mr. Martineau. To show how anti-materialistic my\nown view is, I may, perhaps, without impropriety, quote some out of many\npassages which I have written on the question elsewhere:\n\n     \"Hence though of the two it seems easier to translate so-called\n     Matter into so-called Spirit, than to translate so-called Spirit\n     into so-called Matter (which latter is, indeed, wholly\n     impossible); yet no translation can carry us beyond our\n     symbols.\"[39]\n\nAnd again:\n\n     \"See then our predicament. We can think of Matter only in terms of\n     Mind. We can think of Mind only in terms of Matter. When we have\n     pushed our explorations of the first to the uttermost limit, we are\n     referred to the second for a final answer; and, when we have got\n     the final answer of the second, we are referred back to the first\n     for an interpretation of it. We find the value of _x_ in terms of\n     _y_; then we find the value of _y_ in terms of _x_; and so on we\n     may continue forever without coming nearer to a solution. The\n     antithesis of subject and object, never to be transcended while\n     consciousness lasts, renders impossible all knowledge of that\n     Ultimate Reality in which subject and object are united.\"[40]\n\nIt is thus, I think, manifest that the difference between Mr.\nMartineau's view and the view he opposes is by no means so wide as he\nmakes it appear; and further, it seems to me that such difference as\nexists is rather the reverse of that indicated by his exposition.\nBriefly expressed, the difference is that, where he thinks there is no\nmystery, the doctrine he combats recognizes a mystery. Speaking for\nmyself only, I may say that, agreeing entirely with Mr. Martineau in\nrepudiating the materialistic interpretation as utterly futile, I differ\nfrom him simply in this, that while he says he has found another\ninterpretation, I confess that I cannot find any interpretation; while\nhe holds that he can understand the Power which is manifested in things,\nI feel obliged to admit, after many failures, that I cannot understand\nit. So that, in presence of the transcendent problem which the universe\npresents, Mr. Martineau regards the human intellect as capable, and I as\nincapable. This contrast does not appear to me of the kind which his\nEssay tacitly asserts. If there is such a thing as the \"pride of\nScience,\" it is obviously exceeded by the pride of Theology. I fail to\nperceive humility in the belief that the human mind is able to\ncomprehend that which is behind appearances; and I do not see how piety\nis especially exemplified in the assertion that the Universe contains\nno mode of existence higher in Nature than that which is present to us\nin consciousness. On the contrary, I think it quite a defensible\nproposition that humility is better shown by a confession of\nincompetence to grasp in thought the Cause of all things; and that the\nreligious sentiment may find its highest sphere in the belief that the\nUltimate Power is no more representable in terms of human consciousness\nthan human consciousness is representable in terms of a plant's\nfunctions.\n\nFOOTNOTES:\n\n[Footnote 37: _Principles of Biology_, Sec.Sec. 159-168.]\n\n[Footnote 38: _First Principles_, second edition, Sec. 97.]\n\n[Footnote 39: _Principles of Psychology_, second edition, vol. i., Sec.\n63.]\n\n[Footnote 40: Ibid., Sec. 272.]\n\n\n\n\nTHE FACTORS OF ORGANIC EVOLUTION.\n\n    [_First published in_ The Nineteenth Century_, for April and May_,\n    1886.]\n\n\nI.\n\nWithin the recollection of men now in middle life, opinion concerning\nthe derivation of animals and plants was in a chaotic state. Among the\nunthinking there was tacit belief in creation by miracle, which formed\nan essential part of the creed of Christendom; and among the thinking\nthere were two parties, each of which held an indefensible hypothesis.\nImmensely the larger of these parties, including nearly all whose\nscientific culture gave weight to their judgments, though not accepting\nliterally the theologically-orthodox doctrine, made a compromise between\nthat doctrine and the doctrines which geologists had established; while\nopposed to them were some, mostly having no authority in science, who\nheld a doctrine which was heterodox both theologically and\nscientifically. Professor Huxley, in his lecture on \"The Coming of Age\nof the Origin of Species,\" remarks concerning the first of these parties\nas follows:--\n\n     \"One-and-twenty years ago, in spite of the work commenced by Hutton\n     and continued with rare skill and patience by Lyell, the dominant\n     view of the past history of the earth was catastrophic. Great and\n     sudden physical revolutions, wholesale creations and extinctions of\n     living beings, were the ordinary machinery of the geological epic\n     brought into fashion by the misapplied genius of Cuvier. It was\n     gravely maintained and taught that the end of every geological\n     epoch was signalised by a cataclysm, by which every living being on\n     the globe was swept away, to be replaced by a brand-new creation\n     when the world returned to quiescence. A scheme of nature which\n     appeared to be modelled on the likeness of a succession of rubbers\n     of whist, at the end of each of which the players upset the table\n     and called for a new pack, did not seem to shock anybody.\n\n     I may be wrong, but I doubt if, at the present time, there is a\n     single responsible representative of these opinions left. The\n     progress of scientific geology has elevated the fundament principle\n     of uniformitarianism, that the explanation of the past is to be\n     sought in the study of the present, into the position of an axiom;\n     and the wild speculations of the catastrophists, to which we all\n     listened with respect a quarter of a century ago, would hardly find\n     a single patient hearer at the present day.\"\n\nOf the party above referred to as not satisfied with this conception\ndescribed by Professor Huxley, there were two classes. The great\nmajority were admirers of the _Vestiges of the Natural History of\nCreation_--a work which, while it sought to show that organic evolution\nhas taken place, contended that the cause of organic evolution, is \"an\nimpulse\" supernaturally \"imparted to the forms of life, advancing them,\n... through grades of organization.\" Being nearly all very inadequately\nacquainted with the facts, those who accepted the view set forth in the\n_Vestiges_ were ridiculed by the well-instructed for being satisfied\nwith evidence, much of which was either invalid or easily cancelled by\ncounter-evidence, and at the same time they exposed themselves to the\nridicule of the more philosophical for being content with a supposed\nexplanation which was in reality no explanation: the alleged \"impulse\"\nto advance giving us no more help in understanding the facts than does\nNature's alleged \"abhorrence of a vacuum\" help us to understand the\nascent of water in a pump. The remnant, forming the second of these\nclasses, was very small. While rejecting this mere verbal solution,\nwhich both Dr. Erasmus Darwin and Lamarck had shadowed forth in other\nlanguage, there were some few who, rejecting also the hypothesis\nindicated by both Dr. Darwin and Lamarck, that the promptings of desires\nor wants produced growths of the parts subserving them, accepted the\nsingle _vera causa_ assigned by these writers--the modification of\nstructures resulting from modification of functions. They recognized\nas the sole process in organic development, the adaptation of parts and\npowers consequent on the effects of use and disuse--that continual\nmoulding and re-moulding of organisms to suit their circumstances, which\nis brought about by direct converse with such circumstances.\n\nBut while this cause accepted by these few is a true cause, since\nunquestionably during the life of the individual organism changes of\nfunction produce changes of structure; and while it is a tenable\nhypothesis that changes of structure so produced are inheritable; yet it\nwas manifest to those not prepossessed, that this cause cannot with\nreason be assigned for the greater part of the facts. Though in plants\nthere are some characters which may not irrationally be ascribed to the\ndirect effects of modified functions consequent on modified\ncircumstances, yet the majority of the traits presented by plants are\nnot to be thus explained. It is impossible that the thorns by which a\nbriar is in large measure defended against browsing animals, can have\nbeen developed and moulded by the continuous exercise of their\nprotective actions; for in the first place, the great majority of the\nthorns are never touched at all, and, in the second place, we have no\nground whatever for supposing that those which are touched are thereby\nmade to grow, and to take those shapes which render them efficient.\nPlants which are rendered uneatable by the thick woolly coatings of\ntheir leaves, cannot have had these coatings produced by any process of\nreaction against the action of enemies; for there is no imaginable\nreason why, if one part of a plant is eaten, the rest should thereafter\nbegin to develop the hairs on its surface. By what direct effect of\nfunction on structure, can the shell of a nut have been evolved? Or how\ncan those seeds which contain essential oils, rendering them unpalatable\nto birds, have been made to secrete such essential oils by these actions\nof birds which they restrain? Or how can the delicate plumes borne by\nsome seeds, and giving the wind power to waft them to new stations, be\ndue to any immediate influences of surrounding conditions? Clearly in\nthese and in countless other cases, change of structure cannot have been\ndirectly caused by change of function. So is it with animals to a large\nextent, if not to the same extent. Though we have proof that by rough\nusage the dermal layer may be so excited as to produce a greatly\nthickened epidermal layer, sometimes quite horny; and though it is a\nfeasible hypothesis that an effect of this kind persistently produced\nmay be inherited; yet no such cause can explain the carapace of the\nturtle, the armour of the armadillo, or the imbricated covering of the\nmanis. The skins of these animals are no more exposed to habitual hard\nusage than are those of animals covered by hair. The strange\nexcrescences which distinguish the heads of the hornbills, cannot\npossibly have arisen from any reaction against the action of surrounding\nforces; for even were they clearly protective, there is no reason to\nsuppose that the heads of these birds need protection more than the\nheads of other birds. If, led by the evidence that in animals the amount\nof covering is in some cases affected by the degree of exposure, it were\nadmitted as imaginable that the development of feathers from preceding\ndermal growths had resulted from that extra nutrition caused by extra\nsuperficial circulation, we should still be without explanation of the\nstructure of a feather. Nor should we have any clue to the specialities\nof feathers--the crests of various birds, the tails sometimes so\nenormous, the curiously placed plumes of the bird of paradise, &c., &c.\nStill more obviously impossible is it to explain as due to use or disuse\nthe colours of animals. No direct adaptation to function could have\nproduced the blue protuberances on a mandril's face, or the striped hide\nof a tiger, or the gorgeous plumage of a kingfisher, or the eyes in a\npeacock's tail, or the multitudinous patterns of insects' wings. One\nsingle case, that of a deer's horns, might alone have sufficed to show\nhow insufficient was the assigned cause. During their growth, a deer's\nhorns are not used at all; and when, having been cleared of the dead\nskin and dried-up blood-vessels covering them, they are ready for use,\nthey are nerveless and non-vascular, and hence are incapable of\nundergoing any changes of structure consequent on changes of function.\n\nOf these few then, who rejected the belief described by Professor\nHuxley, and who, espousing the belief in a continuous evolution, had to\naccount for this evolution, it must be said that though the cause\nassigned was a true cause, yet, even admitting that it operated through\nsuccessive generations, it left unexplained the greater part of the\nfacts. Having been myself one of these few, I look back with surprise at\nthe way in which the facts which were congruous with the espoused view\nmonopolized consciousness and kept out the facts which were incongruous\nwith it--conspicuous though many of them were. The misjudgment was not\nunnatural. Finding it impossible to accept any doctrine which implied a\nbreach in the uniform course of natural causation, and, by implication,\naccepting as unquestionable the origin and development of all organic\nforms by accumulated modifications naturally caused, that which appeared\nto explain certain classes of these modifications, was supposed to be\ncapable of explaining the rest: the tendency being to assume that these\nwould eventually be similarly accounted for, though it was not clear\nhow.\n\nReturning from this parenthetic remark, we are concerned here chiefly to\nremember that, as said at the outset, there existed thirty years ago, no\ntenable theory about the genesis of living things. Of the two\nalternative beliefs, neither would bear critical examination.\n\n       *       *       *       *       *\n\nOut of this dead lock we were released--in large measure, though not I\nbelieve entirely--by the _Origin of Species_. That work brought into\nview a further factor; or rather, such factor, recognized as in\noperation by here and there an observer (as pointed out by Mr. Darwin in\nhis introduction to the second edition), was by him for the first time\nseen to have played so immense a part in the genesis of plants and\nanimals.\n\nThough laying myself open to the charge of telling a thrice-told tale, I\nfeel obliged here to indicate briefly the several great classes of facts\nwhich Mr. Darwin's hypothesis explains; because otherwise that which\nfollows would scarcely be understood. And I feel the less hesitation in\ndoing this because the hypothesis which it replaced, not very widely\nknown at any time, has of late so completely dropped into the\nbackground, that the majority of readers are scarcely aware of its\nexistence, and do not therefore understand the relation between Mr.\nDarwin's successful interpretation and the preceding unsuccessful\nattempt at interpretation. Of these classes of facts, four chief ones\nmay be here distinguished.\n\nIn the first place, such adjustments as those exemplified above are made\ncomprehensible. Though it is inconceivable that a structure like that of\nthe pitcher-plant could have been produced by accumulated effects of\nfunction on structure; yet it is conceivable that successive selections\nof favourable variations might have produced it; and the like holds of\nthe no less remarkable appliance of the Venus's Fly-trap, or the still\nmore astonishing one of that water-plant by which infant-fish are\ncaptured. Though it is impossible to imagine how, by direct influence of\nincreased use, such dermal appendages as a porcupine's quills could have\nbeen developed; yet, profiting as the members of a species otherwise\ndefenceless might do by the stiffness of their hairs, rendering them\nunpleasant morsels to eat, it is a feasible supposition that from\nsuccessive survivals of individuals thus defended in the greatest\ndegrees, and the consequent growth in successive generations of hairs\ninto bristles, bristles into spines, spines into quills (for all these\nare homologous), this change could have arisen. In like manner, the odd\ninflatable bag of the bladder-nosed seal, the curious fishing-rod with\nits worm-like appendage carried on the head of the _lophius_ or angler,\nthe spurs on the wings of certain birds, the weapons of the sword-fish\nand saw-fish, the wattles of fowls, and numberless such peculiar\nstructures, though by no possibility explicable as due to effects of use\nor disuse, are explicable as resulting from natural selection operating\nin one or other way.\n\nIn the second place, while showing us how there have arisen countless\nmodifications in the forms, structures, and colours of each part, Mr.\nDarwin has shown us how, by the establishment of favourable variations,\nthere may arise new parts. Though the first step in the production of\nhorns on the heads of various herbivorous animals, may have been the\ngrowth of callosities consequent on the habit of butting--such\ncallosities thus functionally initiated being afterwards developed in\nthe most advantageous ways by selection; yet no explanation can be thus\ngiven of the sudden appearance of a duplicate set of horns, as\noccasionally happens in sheep: an addition which, where it proved\nbeneficial, might readily be made a permanent trait by natural\nselection. Again, the modifications which follow use and disuse can by\nno possibility account for changes in the numbers of vertebrae; but after\nrecognizing spontaneous, or rather fortuitous, variation as a factor, we\ncan see that where an additional vertebra hence resulting (as in some\npigeons) proves beneficial, survival of the fittest may make it a\nconstant character; and there may, by further like additions, be\nproduced extremely long strings of vertebrae, such as snakes show us.\nSimilarly with the mammary glands. It is not an unreasonable supposition\nthat by the effects of greater or less function, inherited through\nsuccessive generations, these may be enlarged or diminished in size; but\nit is out of the question to allege such a cause for changes in their\nnumbers. There is no imaginable explanation of these save the\nestablishment by inheritance of spontaneous variations, such as are\nknown to occur in the human race.\n\nSo too, in the third place, with certain alterations in the connexions\nof parts. According to the greater or smaller demands made on this or\nthat limb, the muscles moving it may be augmented or diminished in bulk;\nand, if there is inheritance of changes so wrought, the limb may, in\ncourse of generations, be rendered larger or smaller. But changes in the\narrangements or attachments of muscles cannot be thus accounted for. It\nis found, especially at the extremities, that the relations of tendons\nto bones and to one another are not always the same. Variations in their\nmodes of connexion may occasionally prove advantageous, and may thus\nbecome established. Here again, then, we have a class of structural\nchanges to which Mr. Darwin's hypothesis gives us the key, and to which\nthere is no other key.\n\nOnce more there are the phenomena of mimicry. Perhaps in a more striking\nway than any others, these show how traits which seem inexplicable are\nexplicable as due to the more frequent survival of individuals that have\nvaried in favourable ways. We are enabled to understand such marvellous\nsimulations as those of the leaf-insect, those of beetles which\n\"resemble glittering dew-drops upon the leaves;\" those of caterpillars\nwhich, when asleep, stretch themselves out so as to look like twigs. And\nwe are shown how there have arisen still more astonishing\nimitations--those of one insect by another. As Mr. Bates has proved,\nthere are cases in which a species of butterfly, rendered so unpalatable\nto insectivorous birds by its disagreeable taste that they will not\ncatch it, is simulated in its colours and markings by a species which is\nstructurally quite different--so simulated that even a practised\nentomologist is liable to be deceived: the explanation being that an\noriginal slight resemblance, leading to occasional mistakes on the part\nof birds, was increased generation after generation by the more frequent\nescape of the most-like individuals, until the likeness became thus\ngreat.\n\nBut now, recognizing in full this process brought into clear view by Mr.\nDarwin, and traced out by him with so much care and skill, can we\nconclude that, taken alone, it accounts for organic evolution? Has the\nnatural selection of favourable variations been the sole factor? On\ncritically examining the evidence, we shall find reason to think that it\nby no means explains all that has to be explained. Omitting for the\npresent any consideration of a factor which may be distinguished as\nprimordial, it may be contended that the above-named factor alleged by\nDr. Erasmus Darwin and by Lamarck, must be recognized as a co-operator.\nUtterly inadequate to explain the major part of the facts as is the\nhypothesis of the inheritance of functionally-produced modifications,\nyet there is a minor part of the facts, very extensive though less,\nwhich must be ascribed to this cause.\n\n       *       *       *       *       *\n\nWhen discussing the question more than twenty years ago (_Principles of\nBiology_, Sec. 166), I instanced the decreased size of the jaws in the\ncivilized races of mankind, as a change not accounted for by the natural\nselection of favourable variations; since no one of the decrements by\nwhich, in thousands of years, this reduction has been effected, could\nhave given to an individual in which it occurred, such advantage as\nwould cause his survival, either through diminished cost of local\nnutrition or diminished weight to be carried. I did not then exclude, as\nI might have done, two other imaginable causes. It may be said that\nthere is some organic correlation between increased size of brain and\ndecreased size of jaw: Camper's doctrine of the facial angle being\nreferred to in proof. But this argument may be met by pointing to the\nmany examples of small-jawed people who are also small-brained, and by\nciting not infrequent cases of individuals remarkable for their mental\npowers, and at the same time distinguished by jaws not less than the\naverage but greater. Again, if sexual selection be named as a possible\ncause, there is the reply that, even supposing such slight diminution of\njaw as took place in a single generation to have been an attraction, yet\nthe other incentives to choice on the part of men have been too many and\ngreat to allow this one to weigh in an adequate degree; while, during\nthe greater portion of the period, choice on the part of women has\nscarcely operated: in earlier times they were stolen or bought, and in\nlater times mostly coerced by parents. Thus, reconsideration of the\nfacts does not show me the invalidity of the conclusion drawn, that this\ndecrease in size of jaw can have had no other cause than continued\ninheritance of those diminutions consequent on diminutions of function,\nimplied by the use of selected and well-prepared food. Here, however, my\nchief purpose is to add an instance showing, even more clearly, the\nconnexion between change of function and change of structure. This\ninstance, allied in nature to the other, is presented by those\nvarieties, or rather sub-varieties, of dogs, which, having been\nhousehold pets, and habitually fed on soft food, have not been called on\nto use their jaws in tearing and crunching, and have been but rarely\nallowed to use them in catching prey and in fighting. No inference can\nbe drawn from the sizes of the jaws themselves, which, in these dogs,\nhave probably been shortened mainly by selection. To get direct proof of\nthe decrease of the muscles concerned in closing the jaws or biting,\nwould require a series of observations very difficult to make. But it is\nnot difficult to get indirect proof of this decrease by looking at the\nbony structures with which these muscles are connected. Examination of\nthe skulls of sundry indoor dogs contained in the Museum of the College\nof Surgeons, proves the relative smallness of such parts. The only\npug-dog's skull is that of an individual not perfectly adult; and though\nits traits are quite to the point they cannot with safety be taken as\nevidence. The skull of a toy-terrier has much restricted areas of\ninsertion for the temporal muscles; has weak zygomatic arches; and has\nextremely small attachments for the masseter muscles. Still more\nsignificant is the evidence furnished by the skull of a King Charles's\nspaniel, which, if we allow three years to a generation, and bear in\nmind that the variety must have existed before Charles the Second's\nreign, we may assume belongs to something approaching to the hundredth\ngeneration of these household pets. The relative breadth between the\nouter surfaces of the zygomatic arches is conspicuously small; the\nnarrowness of the temporal fossae is also striking; the zygomata are very\nslender; the temporal muscles have left no marks whatever, either by\nlimiting lines or by the character of the surfaces covered; and the\nplaces of attachment for the masseter muscles are very feebly developed.\nAt the Museum of Natural History, among skulls of dogs there is one\nwhich, though unnamed, is shown by its small size and by its teeth, to\nhave belonged to one variety or other of lap-dogs, and which has the\nsame traits in an equal degree with the skull just described. Here,\nthen, we have two if not three kinds of dogs which, similarly leading\nprotected and pampered lives, show that in the course of generations the\nparts concerned in clenching the jaws have dwindled. To what cause must\nthis decrease be ascribed? Certainly not to artificial selection; for\nmost of the modifications named make no appreciable external signs: the\nwidth across the zygomata could alone be perceived. Neither can natural\nselection have had anything to do with it; for even were there any\nstruggle for existence among such dogs, it cannot be contended that any\nadvantage in the struggle could be gained by an individual in which a\ndecrease took place. Economy of nutrition, too, is excluded. Abundantly\nfed as such dogs are, the constitutional tendency is to find places\nwhere excess of absorbed nutriment may be conveniently deposited, rather\nthan to find places where some cutting down of the supplies is\npracticable. Nor again can there be alleged a possible correlation\nbetween these diminutions and that shortening of the jaws which has\nprobably resulted from selection; for in the bull-dog, which has also\nrelatively short jaws, these structures concerned in closing them are\nunusually large. Thus there remains as the only conceivable cause, the\ndiminution of size which results from diminished use. The dwindling of a\nlittle-exercised part has, by inheritance, been made more and more\nmarked in successive generations.\n\n       *       *       *       *       *\n\nDifficulties of another class may next be exemplified--those which\npresent themselves when we ask how there can be effected by the\nselection of favourable variations, such changes of structure as adapt\nan organism to some useful action in which many different parts\nco-operate. None can fail to see how a simple part may, in course of\ngenerations, be greatly enlarged, if each enlargement furthers, in some\ndecided way, maintenance of the species. It is easy to understand, too,\nhow a complex part, as an entire limb, may be increased as a whole by\nthe simultaneous due increase of its co-operative parts; since if, while\nit is growing, the channels of supply bring to the limb an unusual\nquantity of blood, there will naturally result a proportionately greater\nsize of all its components--bones, muscles, arteries, veins, &c. But\nthough in cases like this, the co-operative parts forming some large\ncomplex part may be expected to vary together, nothing implies that they\nnecessarily do so; and we have proof that in various cases, even when\nclosely united, they do not do so. An example is furnished by those\nblind crabs named in the _Origin of Species_ which inhabit certain dark\ncaves of Kentucky, and which, though they have lost their eyes, have\nnot lost the foot-stalks which carried their eyes. In describing the\nvarieties which have been produced by pigeon-fanciers, Mr. Darwin notes\nthe fact that along with changes in length of beak produced by\nselection, there have not gone proportionate changes in length of\ntongue. Take again the case of teeth and jaws. In mankind these have not\nvaried together. During civilization the jaws have decreased, but the\nteeth have not decreased in proportion; and hence that prevalent\ncrowding of them, often remedied in childhood by extraction of some, and\nin other cases causing that imperfect development which is followed by\nearly decay. But the absence of proportionate variation in co-operative\nparts that are close together, and are even bound up in the same mass,\nis best seen in those varieties of dogs named above as illustrating the\ninherited effects of disuse. We see in them, as we see in the human\nrace, that diminution in the jaws has not been accompanied by\ncorresponding diminution in the teeth. In the catalogue of the College\nof Surgeons Museum, there is appended to the entry which identifies a\nBlenheim Spaniel's skull, the words--\"the teeth are closely crowded\ntogether,\" and to the entry concerning the skull of a King Charles's\nSpaniel the words--\"the teeth are closely packed, p. 3, is placed quite\ntransversely to the axis of the skull.\" It is further noteworthy that in\na case where there is no diminished use of the jaws, but where they have\nbeen shortened by selection, a like want of concomitant variation is\nmanifested: the case being that of the bull-dog, in the upper jaw of\nwhich also, \"the premolars ... are excessively crowded, and placed\nobliquely or even transversely to the long axis of the skull.\"[41]\n\nIf, then, in cases where we can test it, we find no concomitant\nvariation in co-operative parts that are near together--if we do not\nfind it in parts which, though belonging to different tissues, are so\nclosely united as teeth and jaws--if we do not find it even when the\nco-operative parts are not only closely united, but are formed out of\nthe same tissue, like the crab's eye and its peduncle; what shall we say\nof co-operative parts which, besides being composed of different\ntissues, are remote from one another? Not only are we forbidden to\nassume that they vary together, but we are warranted in asserting that\nthey can have no tendency to vary together. And what are the\nimplications in cases where increase of a structure can be of no service\nunless there is concomitant increase in many distant structures, which\nhave to join it in performing the action for which it is useful?\n\nAs far back as 1864 (_Principles of Biology_, Sec. 166) I named in\nillustration an animal carrying heavy horns--the extinct Irish elk; and\nindicated the many changes in bones, muscles, blood-vessels, nerves,\ncomposing the fore-part of the body, which would be required to make an\nincrement of size in such horns advantageous. Here let me take another\ninstance--that of the giraffe: an instance which I take partly because,\nin the sixth edition of the _Origin of Species_, issued in 1872, Mr.\nDarwin has referred to this animal when effectually disposing of certain\narguments urged against his hypothesis. He there says:--\n\n     \"In order that an animal should acquire some structure specially\n     and largely developed, it is almost indispensable that several\n     other parts should be modified and co-adapted. Although every part\n     of the body varies slightly, it does not follow that the necessary\n     parts should always vary in the right direction and to the right\n     degree\" (p. 179).\n\nAnd in the summary of the chapter, he remarks concerning the adjustments\nin the same quadruped, that \"the prolonged use of all the parts together\nwith inheritance will have aided in an important manner in their\nco-ordination\" (p. 199): a remark probably having reference chiefly to\nthe increased massiveness of the lower part of the neck; the increased\nsize and strength of the thorax required to bear the additional burden;\nand the increased strength of the fore-legs required to carry the\ngreater weight of both. But now I think that further consideration\nsuggests the belief that the entailed modifications are much more\nnumerous and remote than at first appears; and that the greater part of\nthese are such as cannot be ascribed in any degree to the selection of\nfavourable variations, but must be ascribed exclusively to the inherited\neffects of changed functions. Whoever has seen a giraffe gallop will\nlong remember the sight as a ludicrous one. The reason for the\nstrangeness of the motions is obvious. Though the fore limbs and the\nhind limbs differ so much in length, yet in galloping they have to keep\npace--must take equal strides. The result is that at each stride, the\nangle which the hind limbs describe round their centre of motion is much\nlarger than the angle described by the fore limbs. And beyond this, as\nan aid in equalizing the strides, the hind part of the back is at each\nstride bent very much downwards and forwards. Hence the hind-quarters\nappear to be doing nearly all the work. Now a moment's observation shows\nthat the bones and muscles composing the hind-quarters of the giraffe,\nperform actions differing in one or other way and degree, from the\nactions performed by the homologous bones and muscles in a mammal of\nordinary proportions, and from those in the ancestral mammal which gave\norigin to the giraffe. Each further stage of that growth which produced\nthe large fore-quarters and neck, entailed some adapted change in sundry\nof the numerous parts composing the hind-quarters; since any failure in\nthe adjustment of their respective strengths would entail some defect in\nspeed and consequent loss of life when chased. It needs but to remember\nhow, when continuing to walk with a blistered foot, the taking of steps\nin such a modified way as to diminish pressure on the sore point, soon\nproduces aching of muscles which are called into unusual action, to see\nthat over-straining of any one of the muscles of the giraffe's\nhind-quarters might quickly incapacitate the animal when putting out all\nits powers to escape; and to be a few yards behind others would cause\ndeath. Hence if we are debarred from assuming that co-operative parts\nvary together even when adjacent and closely united--if we are still\nmore debarred from assuming that with increased length of fore-legs or\nof neck, there will go an appropriate change in any one muscle or bone\nin the hind-quarters; how entirely out of the question it is to assume\nthat there will simultaneously take place the appropriate changes in\n_all_ those many components of the hind-quarters which severally require\nre-adjustment. It is useless to reply that an increment of length in the\nfore-legs or neck might be retained and transmitted to posterity,\nwaiting an appropriate variation in a particular bone or muscle in the\nhind-quarters, which, being made, would allow of a further increment.\nFor besides the fact that until this secondary variation occurred the\nprimary variation would be a disadvantage often fatal; and besides the\nfact that before such an appropriate secondary variation might be\nexpected in the course of generations to occur, the primary variation\nwould have died out; there is the fact that the appropriate variation of\none bone or muscle in the hind-quarters would be useless without\nappropriate variations of all the rest--some in this way and some in\nthat--a number of appropriate variations which it is impossible to\nsuppose.\n\nNor is this all. Far more numerous appropriate variations would be\nindirectly necessitated. The immense change in the ratio of\nfore-quarters to hind-quarters would make requisite a corresponding\nchange of ratio in the appliances carrying on the nutrition of the two.\nThe entire vascular system, arterial and veinous, would have to undergo\nsuccessive unbuildings and rebuildings to make its channels everywhere\nadequate to the local requirements; since any want of adjustment in the\nblood-supply in this or that set of muscles, would entail incapacity,\nfailure of speed, and loss of life. Moreover the nerves supplying the\nvarious sets of muscles would have to be proportionately changed; as\nwell as the central nervous tracts from which they issued. Can we\nsuppose that all these appropriate changes, too, would be step by step\nsimultaneously made by fortunate spontaneous variations, occurring along\nwith all the other fortunate spontaneous variations? Considering how\nimmense must be the number of these required changes, added to the\nchanges above enumerated, the chances against any adequate\nre-adjustments fortuitously arising must be infinity to one.\n\nIf the effects of use and disuse of parts are inheritable, then any\nchange in the fore parts of the giraffe which affects the action of the\nhind limbs and back, will simultaneously cause, by the greater or less\nexercise of it, a re-moulding of each component in the hind limbs and\nback in a way adapted to the new demands; and generation after\ngeneration the entire structure of the hind-quarters will be\nprogressively fitted to the changed structure of the fore-quarters: all\nthe appliances for nutrition and innervation being at the same time\nprogressively fitted to both. But in the absence of this inheritance of\nfunctionally-produced modifications, there is no seeing how the required\nre-adjustments can be made.\n\n       *       *       *       *       *\n\nYet a third class of difficulties stands in the way of the belief that\nthe natural selection of useful variations is the sole factor of organic\nevolution. This class of difficulties, already pointed out in Sec. 166 of\nthe _Principles of Biology_, I cannot more clearly set forth than in the\nwords there used. Hence I may perhaps be excused for here quoting them.\n\n     \"Where the life is comparatively simple, or where surrounding\n     circumstances render some one function supremely important, the\n     survival of the fittest may readily bring about the appropriate\n     structural change, without any aid from the transmission of\n     functionally-acquired modifications. But in proportion as the life\n     grows complex--in proportion as a healthy existence cannot be\n     secured by a large endowment of some one power, but demands many\n     powers; in the same proportion do there arise obstacles to the\n     increase of any particular power, by 'the preservation of favoured\n     races in the struggle for life.' As fast as the faculties are\n     multiplied, so fast does it become possible for the several members\n     of a species to have various kinds of superiorities over one\n     another. While one saves its life by higher speed, another does the\n     like by clearer vision, another by keener scent, another by quicker\n     hearing, another by greater strength, another by unusual power of\n     enduring cold or hunger, another by special sagacity, another by\n     special timidity, another by special courage; and others by other\n     bodily and mental attributes. Now it is unquestionably true that,\n     other things equal, each of these attributes, giving its possessor\n     an extra chance of life, is likely to be transmitted to posterity.\n     But there seems no reason to suppose that it will be increased in\n     subsequent generations by natural selection. That it may be thus\n     increased, the individuals not possessing more than average\n     endowments of it, must be more frequently killed off than\n     individuals highly endowed with it; and this can happen only when\n     the attribute is one of greater importance, for the time being,\n     than most of the other attributes. If those members of the species\n     which have but ordinary shares of it, nevertheless survive by\n     virtue of other superiorities which they severally possess; then it\n     is not easy to see how this particular attribute can be developed\n     by natural selection in subsequent generations. The probability\n     seems rather to be, that by gamogenesis, this extra endowment will,\n     on the average, be diminished in posterity--just serving in the\n     long run to compensate the deficient endowments of other\n     individuals, whose special powers lie in other directions; and so\n     to keep up the normal structure of the species. The working out of\n     the process is here somewhat difficult to follow; but it appears to\n     me that as fast as the number of bodily and mental faculties\n     increases, and as fast as the maintenance of life comes to depend\n     less on the amount of any one, and more on the combined action of\n     all; so fast does the production of specialities of character by\n     natural selection alone, become difficult. Particularly does this\n     seem to be so with a species so multitudinous in its powers as\n     mankind; and above all does it seem to be so with such of the human\n     powers as have but minor shares in aiding the struggle for\n     life--the aesthetic faculties, for example.\"\n\nDwelling for a moment on this last illustration of the class of\ndifficulties described, let us ask how we are to interpret the\ndevelopment of the musical faculty. I will not enlarge on the family\nantecedents of the great composers. I will merely suggest the inquiry\nwhether the greater powers possessed by Beethoven and Mozart, by Weber\nand Rossini, than by their fathers, were not due in larger measure to\nthe inherited effects of daily exercise of the musical faculty by their\nfathers, than to inheritance, with increase, of spontaneous variations;\nand whether the diffused musical powers of the Bach clan, culminating in\nthose of Johann Sebastian, did not result in part from constant\npractice; but I will raise the more general question--How came there\nthat endowment of musical faculty which characterizes modern Europeans\nat large, as compared with their remote ancestors. The monotonous chants\nof low savages cannot be said to show any melodic inspiration; and it is\nnot evident that an individual savage who had a little more musical\nperception than the rest, would derive any such advantage in the\nmaintenance of life as would secure the spread of his superiority by\ninheritance of the variation. And then what are we to say of harmony? We\ncannot suppose that the appreciation of this, which is relatively\nmodern, can have arisen by descent from the men in whom successive\nvariations increased the appreciation of it--the composers and musical\nperformers; for on the whole, these have been men whose worldly\nprosperity was not such as enabled them to rear many children inheriting\ntheir special traits. Even if we count the illegitimate ones, the\nsurvivors of these added to the survivors of the legitimate ones, can\nhardly be held to have yielded more than average numbers of descendants;\nand those who inherited their special traits have not often been thereby\nso aided in the struggle for existence as to further the spread of such\ntraits. Rather the tendency seems to have been the reverse.\n\nSince the above passage was written, I have found in the second volume\nof _Animals and Plants under Domestication_, a remark made by Mr.\nDarwin, practically implying that among creatures which depend for their\nlives on the efficiency of numerous powers, the increase of any one by\nthe natural selection of a variation is necessarily difficult. Here it\nis.\n\n     \"Finally, as indefinite and almost illimitable variability is the\n     usual result of domestication and cultivation, with the same part\n     or organ varying in different individuals in different or even in\n     directly opposite ways; and as the same variation, if strongly\n     pronounced, usually recurs only after long intervals of time, any\n     particular variation would generally be lost by crossing,\n     reversion, and the accidental destruction of the varying\n     individuals, unless carefully preserved by man.\"--Vol. ii, 292.\n\nRemembering that mankind, subject as they are to this domestication and\ncultivation, are not, like domesticated animals, under an agency which\npicks out and preserves particular variations; it results that there\nmust usually be among them, under the influence of natural selection\nalone, a continual disappearance of any useful variations of particular\nfaculties which may arise. Only in cases of variations which are\nspecially preservative, as for example, great cunning during a\nrelatively barbarous state, can we expect increase from natural\nselection alone. We cannot suppose that minor traits, exemplified among\nothers by the aesthetic perceptions, can have been evolved by natural\nselection. But if there is inheritance of functionally-produced\nmodifications of structure, evolution of such minor traits is no longer\ninexplicable.\n\n       *       *       *       *       *\n\nTwo remarks made by Mr. Darwin have implications from which the same\ngeneral conclusion must, I think, be drawn. Speaking of the variability\nof animals and plants under domestication, he says:--\n\n     \"Changes of any kind in the conditions of life, even extremely\n     slight changes, often suffice to cause variability.... Animals and\n     plants continue to be variable for an immense period after their\n     first domestication; ... In the course of time they can be\n     habituated to certain changes, so as to become less variable; ...\n     There is good evidence that the power of changed conditions\n     accumulates; so that two, three, or more generations must be\n     exposed to new conditions before any effect is visible.... Some\n     variations are induced by the direct action of the surrounding\n     conditions on the whole organization, or on certain parts alone,\n     and other variations are induced indirectly through the\n     reproductive system being affected in the same manner as is so\n     common with organic beings when removed from their natural\n     conditions.\"--(_Animals and Plants under Domestication_, vol. ii,\n     270.)\n\nThere are to be recognized two modes of this effect produced by changed\nconditions on the reproductive system, and consequently on offspring.\nSimple arrest of development is one. But beyond the variations of\noffspring arising from imperfectly developed reproductive systems in\nparents--variations which must be ordinarily in the nature of\nimperfections--there are others due to a changed balance of functions\ncaused by changed conditions. The fact noted by Mr. Darwin in the above\npassage, \"that the power of changed conditions accumulates; so that two,\nthree, or more generations must be exposed to new conditions before any\neffect is visible,\" implies that during these generations there is going\non some change of constitution consequent on the changed proportions and\nrelations of the functions. I will not dwell on the implication, which\nseems tolerably clear, that this change must consist of such\nmodifications of organs as adapt them to their changed functions; and\nthat if the influence of changed conditions \"accumulates,\" it must be\nthrough the inheritance of such modifications. Nor will I press the\nquestion--What is the nature of the effect registered in the\nreproductive elements, and which is subsequently manifested by\nvariations?--Is it an effect entirely irrelevant to the new requirements\nof the variety?--Or is it an effect which makes the variety less fit for\nthe new requirements?--Or is it an effect which makes it more fit for\nthe new requirements? But not pressing these questions, it suffices to\npoint out the necessary implication that changed functions of organs\n_do_, in some way or other, register themselves in changed proclivities\nof the reproductive elements. In face of these facts it cannot be denied\nthat the modified action of a part produces an inheritable effect--be\nthe nature of that effect what it may.\n\nThe second of the remarks above adverted to as made by Mr. Darwin, is\ncontained in his sections dealing with correlated variations. In the\n_Origin of Species_, p. 114, he says--\n\n     \"The whole organization is so tied together during its growth and\n     development, that when slight variations in any one part occur, and\n     are accumulated through natural selection, other parts become\n     modified.\"\n\nAnd a parallel statement contained in _Animals and Plants under\nDomestication_, vol. ii, p. 320, runs thus--\n\n     \"Correlated variation is an important subject for us; for when one\n     part is modified through continued selection, either by man or\n     under nature, other parts of the organization will be unavoidably\n     modified. From this correlation it apparently follows that, with\n     our domesticated animals and plants, varieties rarely or never\n     differ from each other by some single character alone.\"\n\nBy what process does a changed part modify other parts? By modifying\ntheir functions in some way or degree, seems the necessary answer. It is\nindeed, imaginable, that where the part changed is some dermal appendage\nwhich, becoming larger, has abstracted more of the needful material from\nthe general stock, the effect may consist simply in diminishing the\namount of this material available for other dermal appendages, leading\nto diminution of some or all of them, and may fail to affect in\nappreciable ways the rest of the organism: save perhaps the\nblood-vessels near the enlarged appendage. But where the part is an\nactive one--a limb, or viscus, or any organ which constantly demands\nblood, produces waste matter, secretes, or absorbs--then all the other\nactive organs become implicated in the change. The functions performed\nby them have to constitute a moving equilibrium; and the function of one\ncannot, by alteration of the structure performing it, be modified in\ndegree or kind, without modifying the functions of the rest--some\nappreciably and others inappreciably, according to the directness or\nindirectness of their relations. Of such inter-dependent changes, the\nnormal ones are naturally inconspicuous; but those which are partially\nor completely abnormal, sufficiently carry home the general truth. Thus,\nunusual cerebral excitement affects the excretion through the kidneys in\nquantity or quality or both. Strong emotions of disagreeable kinds check\nor arrest the flow of bile. A considerable obstacle to the circulation\noffered by some important structure in a diseased or disordered state,\nthrowing more strain upon the heart, causes hypertrophy of its muscular\nwalls; and this change which is, so far as concerns the primary evil, a\nremedial one, often entails mischiefs in other organs. \"Apoplexy and\npalsy, in a scarcely credible number of cases, are directly dependent on\nhypertrophic enlargement of the heart.\" And in other cases, asthma,\ndropsy, and epilepsy are caused. Now if a result of this\ninter-dependence as seen in the individual organism, is that a local\nmodification of one part produces, by changing their functions,\ncorrelative modifications of other parts, then the question here to be\nput is--Are these correlative modifications, when of a kind falling\nwithin normal limits, inheritable or not. If they are inheritable, then\nthe fact stated by Mr. Darwin that \"when one part is modified through\ncontinued selection,\" \"other parts of the organization will be\nunavoidably modified\" is perfectly intelligible: these entailed\nsecondary modifications are transmitted _pari passu_ with the successive\nmodifications produced by selection. But what if they are not\ninheritable? Then these secondary modifications caused in the\nindividual, not being transmitted to descendants, the descendants must\ncommence life with organizations out of balance, and with each increment\nof change in the part affected by selection, their organizations must\nget more out of balance--must have a larger and larger amounts of\nre-organization to be made during their lives. Hence the constitution of\nthe variety must become more and more unworkable.\n\nThe only imaginable alternative is that the re-adjustments are effected\nin course of time by natural selection. But, in the first place, as we\nfind no proof of concomitant variation among directly co-operative parts\nwhich are closely united, there cannot be assumed any concomitant\nvariation among parts which are both indirectly co-operative and far\nfrom one another. And, in the second place, before all the many\nrequired re-adjustments could be made, the variety would die out from\ndefective constitution. Even were there no such difficulty, we should\nstill have to entertain a strange group of propositions, which would\nstand as follows:--1. Change in one part entails, by reaction on the\norganism, changes, in other parts, the functions of which are\nnecessarily changed. 2. Such changes worked in the individual, affect,\nin some way, the reproductive elements: these being found to evolve\nunusual structures when the constitutional balance has been continuously\ndisturbed. 3. But the changes in the reproductive elements thus caused,\nare not such as represent these functionally-produced changes: the\nmodifications conveyed to offspring are irrelevant to these various\nmodifications functionally produced in the organs of the parents. 4.\nNevertheless, while the balance of functions cannot be re-established\nthrough inheritance of the effects of disturbed functions on structures,\nwrought throughout the individual organism; it can be re-established by\nthe inheritance of fortuitous variations which occur in all the affected\norgans without reference to these changes of function.\n\nNow without saying that acceptance of this group of propositions is\nimpossible, we may certainly say that it is not easy.\n\n       *       *       *       *       *\n\n\"But where are the direct proofs that inheritance of\nfunctionally-produced modifications takes place?\" is a question which\nwill be put by those who have committed themselves to the current\nexclusive interpretation. \"Grant that there are difficulties; still,\nbefore the transmitted effects of use and disuse can be legitimately\nassigned in explanation of them, we must have good evidence that the\neffects of use and disuse _are_ transmitted.\"\n\nBefore dealing directly with this demurrer, let me deal with it\nindirectly, by pointing out that the lack of recognized evidence may be\naccounted for without assuming that there is not plenty of it.\nInattention and reluctant attention lead to the ignoring of facts which\nreally exist in abundance; as is well illustrated in the case of\npre-historic implements. Biassed by the current belief that no traces of\nman were to be found on the Earth's surface, save in certain superficial\nformations of very recent date, geologists and anthropologists not only\nneglected to seek such traces, but for a long time continued to\npooh-pooh those who said they had found them. When M. Boucher de Perthes\nat length succeeded in drawing the eyes of scientific men to the flint\nimplements discovered by him in the quarternary deposits of the Somme\nvalley; and when geologists and anthropologists had thus been convinced\nthat evidences of human existence were to be found in formations of\nconsiderable age, and thereafter began to search for them; they found\nplenty of them all over the world. Or again, to take an instance closely\ngermane to the matter, we may recall the fact that the contemptuous\nattitude towards the hypothesis of organic evolution which naturalists\nin general maintained before the publication of Mr. Darwin's work,\nprevented them from seeing the multitudinous facts by which it is\nsupported. Similarly, it is very possible that their alienation from the\nbelief that there is a transmission of those changes of structure which\nare produced by changes of action, makes naturalists slight the evidence\nwhich supports that belief and refuse to occupy themselves in seeking\nfurther evidence.\n\nIf it be asked how it happens that there have been recorded\nmultitudinous instances of variations fortuitously arising and\nre-appearing in offspring, while there have not been recorded instances\nof the transmission of changes functionally produced, there are three\nreplies. The first is that changes of the one class are many of them\nconspicuous, while those of the other class are nearly all\ninconspicuous. If a child is born with six fingers, the anomaly is not\nsimply obvious but so startling as to attract much notice; and if this\nchild, growing up, has six-fingered descendents, everybody in the\nlocality hears of it. A pigeon with specially-coloured feathers, or one\ndistinguished by a broadened and upraised tail, or by a protuberance of\nthe neck, draws attention by its oddness; and if in its young the trait\nis repeated, occasionally with increase, the fact is remarked, and there\nfollows the thought of establishing the peculiarity by selection. A lamb\ndisabled from leaping by the shortness of its legs, could not fail to be\nobserved; and the fact that its offspring were similarly short-legged,\nand had a consequent inability to get over fences, would inevitably\nbecome widely known. Similarly with plants. That this flower had an\nextra number of petals, that that was unusually symmetrical, and that\nanother differed considerably in colour from the average of its kind,\nwould be easily seen by an observant gardener; and the suspicion that\nsuch anomalies are inheritable having arisen, experiments leading to\nfurther proofs that they are so, would frequently be made. But it is not\nthus with functionally-produced modifications. The seats of these are in\nnearly all cases the muscular, osseous, and nervous systems, and the\nviscera--parts which are either entirely hidden or greatly obscured.\nModification in a nervous centre is inaccessible to vision; bones may be\nconsiderably altered in size or shape without attention being drawn to\nthem; and, covered with thick coats as are most of the animals open to\ncontinuous observation, the increases or decreases in muscles must be\ngreat before they become externally perceptible.\n\nA further important difference between the two inquiries is that to\nascertain whether a fortuitous variation is inheritable, needs merely a\nlittle attention to the selection of individuals and the observation of\noffspring; while to ascertain whether there is inheritance of a\nfunctionally-produced modification, it is requisite to make arrangements\nwhich demand the greater or smaller exercise of some part or parts;\nand it is difficult in many cases to find such arrangements, troublesome\nto maintain them even for one generation, and still more through\nsuccessive generations.\n\nNor is this all. There exist stimuli to inquiry in the one case which do\nnot exist in the other. The money-interest and the interest of the\nfancier, acting now separately and now together, have prompted\nmultitudinous individuals to make experiments which have brought out\nclear evidence that fortuitous variations are inherited. The\ncattle-breeders who profit by producing certain shapes and qualities;\nthe keepers of pet animals who take pride in the perfections of those\nthey have bred; the florists, professional and amateur, who obtain new\nvarieties and take prizes; form a body of men who furnish naturalists\nwith countless of the required proofs. But there is no such body of men,\nled either by pecuniary interest or the interest of a hobby, to\nascertain by experiments whether the effects of use and disuse are\ninheritable.\n\nThus, then, there are amply sufficient reasons why there is a great deal\nof direct evidence in the one case and but little in the other: such\nlittle being that which comes out incidentally. Let us look at what\nthere is of it.\n\n       *       *       *       *       *\n\nConsiderable weight attaches to a fact which Brown-Sequard discovered,\nquite by accident, in the course of his researches. He found that\ncertain artificially-produced lesions of the nervous system, so small\neven as a section of the sciatic nerve, left, after healing, an\nincreasing excitability which ended in liability to epilepsy; and there\nafterwards came out the unlooked-for result that the offspring of\nguinea-pigs which had thus acquired an epileptic habit such that a pinch\non the neck would produce a fit, inherited an epileptic habit of like\nkind. It has, indeed, been since alleged that guinea pigs tend to\nepilepsy, and that phenomena of the kind described, occur where there\nhave been no antecedents like those in Brown-Sequard's case. But\nconsidering the improbability that the phenomena observed by him\nhappened to be nothing more than phenomena which occasionally arise\nnaturally, we may, until there is good proof to the contrary, assign\nsome value to his results.\n\nEvidence not of this directly experimental kind, but nevertheless of\nconsiderable weight, is furnished by other nervous disorders. There is\nproof enough that insanity admits of being induced by circumstances\nwhich, in one or other way, derange the nervous functions--excesses of\nthis or that kind; and no one questions the accepted belief that\ninsanity is inheritable. Is it alleged that the insanity which is\ninheritable is that which spontaneously arises, and that the insanity\nwhich follows some chronic perversion of functions is not inheritable?\nThis does not seem a very reasonable allegation; and until some warrant\nfor it is forthcoming, we may fairly assume that there is here a further\nsupport for belief in the transmission of functionally-produced changes.\n\nMoreover, I find among physicians the belief that nervous disorders of a\nless severe kind are inheritable. Men who have prostrated their nervous\nsystems by prolonged overwork or in some other way, have children more\nor less prone to nervousness. It matters not what may be the form of\ninheritance--whether it be of a brain in some way imperfect, or of a\ndeficient blood-supply; it is in any case the inheritance of\nfunctionally-modified structures.\n\nVerification of the reasons above given for the paucity of this direct\nevidence, is yielded by contemplation of it; for it is observable that\nthe cases named are cases which, from one or other cause, have thrust\nthemselves on observation. They justify the suspicion that it is not\nbecause such cases are rare that many of them cannot be cited; but\nsimply because they are mostly unobtrusive, and to be found only by that\ndeliberate search which nobody makes. I say nobody, but I am wrong.\nSuccessful search has been made by one whose competence as an observer\nis beyond question, and whose testimony is less liable than that of all\nothers to any bias towards the conclusion that such inheritance takes\nplace. I refer to the author of the _Origin of Species_.\n\n       *       *       *       *       *\n\nNow-a-days most naturalists are more Darwinian than Mr. Darwin himself.\nI do not mean that their beliefs in organic evolution are more decided;\nthough I shall be supposed to mean this by the mass of readers, who\nidentify Mr. Darwin's great contribution to the theory of organic\nevolution, with the theory of organic evolution itself, and even with\nthe theory of evolution at large. But I mean that the particular factor\nwhich he first recognized as having played so immense a part in organic\nevolution, has come to be regarded by his followers as the sole factor,\nthough it was not so regarded by him. It is true that he apparently\nrejected altogether the causal agencies alleged by earlier inquirers. In\nthe Historical Sketch prefixed to the later editions of his _Origin of\nSpecies_ (p. xiv, note), he writes:--\"It is curious how largely my\ngrandfather, Dr. Erasmus Darwin, anticipated the views and erroneous\ngrounds of opinion of Lamarck in his 'Zoonomia' (vol. i, pp. 500-510),\npublished in 1794.\" And since, among the views thus referred to, was the\nview that changes of structure in organisms arise by the inheritance of\nfunctionally-produced changes, Mr. Darwin seems, by the above sentence,\nto have implied his disbelief in such inheritance. But he did not mean\nto imply this; for his belief in it as a cause of evolution, if not an\nimportant cause, is proved by many passages in his works. In the first\nchapter of the _Origin of Species_ (p. 8 of the sixth edition), he says\nrespecting the inherited effects of habit, that \"with animals the\nincreased use or disuse of parts has had a more marked influence;\" and\nhe gives as instances the changed relative weights of the wing bones and\nleg bones of the wild duck and the domestic duck, \"the great and\ninherited development of the udders in cows and goats,\" and the drooping\nears of various domestic animals. Here are other passages taken from the\nlatest edition of the work.\n\n     \"I think there can be no doubt that use in our domestic animals has\n     strengthened and enlarged certain parts, and disuse diminished\n     them; and that such modifications are inherited\" (p. 108). [And on\n     the following pages he gives five further examples of such\n     effects.] \"Habit in producing constitutional peculiarities and use\n     in strengthening and disuse in weakening and diminishing organs,\n     appear in many cases to have been potent in their effects\" (p.\n     131). \"When discussing special cases, Mr. Mivart passes over the\n     effects of the increased use and disuse of parts, which I have\n     always maintained to be highly important, and have treated in my\n     'Variation under Domestication' at greater length than, as I\n     believe, any other writer\" (p. 176). \"Disuse, on the other hand,\n     will account for the less developed condition of the whole inferior\n     half of the body, including the lateral fins\" (p. 188). \"I may give\n     another instance of a structure which apparently owes its origin\n     exclusively to use or habit\" (p. 188). \"It appears probable that\n     disuse has been the main agent in rendering organs rudimentary\"\n     (pp. 400-401). \"On the whole, we may conclude that habit, or use\n     and disuse, have, in some cases, played a considerable part in the\n     modification of the constitution and structure; but that the\n     effects have often been largely combined with, and sometimes\n     overmastered by, the natural selection of innate variations\" (p.\n     114).\n\nIn his subsequent work, _The Variation of Animals and Plants under\nDomestication_, where he goes into full detail, Mr. Darwin gives more\nnumerous illustrations of the inherited effects of use and disuse. The\nfollowing are some of the cases, quoted from volume i of the first\nedition.\n\n     Treating of domesticated rabbits, he says:--\"the want of exercise\n     has apparently modified the proportional length of the limbs in\n     comparison with the body\" (p. 116). \"We thus see that the most\n     important and complicated organ [the brain] in the whole\n     organization is subject to the law of decrease in size from disuse\"\n     (p. 129). He remarks that in birds of the oceanic islands \"not\n     persecuted by any enemies, the reduction of their wings has\n     probably been caused by gradual disuse.\" After comparing one of\n     these, the water-hen of Tristan d'Acunha, with the European\n     water-hen, and showing that all the bones concerned in flight are\n     smaller, he adds--\"Hence in the skeleton of this natural species\n     nearly the same changes have occurred, only carried a little\n     further, as with our domestic ducks, and in this latter case I\n     presume no one will dispute that they have resulted from the\n     lessened use of the wings and the increased use of the legs\" (pp.\n     286-7). \"As with other long-domesticated animals, the instincts of\n     the silk-moth have suffered. The caterpillars, when placed on a\n     mulberry-tree, often commit the strange mistake of devouring the\n     base of the leaf on which they are feeding, and consequently fall\n     down; but they are capable, according to M. Robinet, of again\n     crawling up the trunk. Even this capacity sometimes fails, for M.\n     Martins placed some caterpillars on a tree, and those which fell\n     were not able to remount and perished of hunger; they were even\n     incapable of passing from leaf to leaf\" (p. 304).\n\nHere are some instances of like meaning from volume ii.\n\n     \"In many cases there is reason to believe that the lessened use of\n     various organs has affected the corresponding parts in the\n     offspring. But there is no good evidence that this ever follows in\n     the course of a single generation.... Our domestic fowls, ducks,\n     and geese have almost lost, not only in the individual but in the\n     race, their power of flight; for we do not see a chicken, when\n     frightened, take flight like a young pheasant.... With domestic\n     pigeons, the length of the sternum, the prominence of its crest,\n     the length of the scapulae and furcula, the length of the wings as\n     measured from tip to tip of the radius, are all reduced relatively\n     to the same parts in the wild pigeon.\" [After detailing kindred\n     diminutions in fowls and ducks, Mr. Darwin adds] \"The decreased\n     weight and size of the bones, in the foregoing cases, is probably\n     the indirect result of the reaction of the weakened muscles on the\n     bones\" (pp. 297-8). \"Nathusius has shown that, with the improved\n     races of the pig, the shortened legs and snout, the form of the\n     articular condyles of the occiput, and the position of the jaws\n     with the upper canine teeth projecting in a most anomalous manner\n     in front of the lower canines, may be attributed to these parts not\n     having been fully exercised.... These modifications of structure,\n     which are all strictly inherited, characterise several improved\n     breeds, so that they cannot have been derived from any single\n     domestic or wild stock. With respect to cattle, Professor Tanner\n     has remarked that the lungs and liver in the improved breeds 'are\n     found to be considerably reduced in size when compared with those\n     possessed by animals having perfect liberty;' ... The cause of the\n     reduced lungs in highly-bred animals which take little exercise is\n     obvious\" (pp. 299-300). [And on pp. 301, 302 and 303, he gives\n     facts showing the effects of use and disuse in changing, among\n     domestic animals, the characters of the ears, the lengths of the\n     intestines, and, in various ways, the natures of the instincts.]\n\nBut Mr. Darwin's admission, or rather his assertion, that the\ninheritance of functionally-produced modifications has been a factor in\norganic evolution, is made clear not by these passages alone and by\nkindred ones. It is made clearer still by a passage in the preface to\nthe second edition of his _Descent of Man_. He there protests against\nthat current version of his views in which this factor makes no\nappearance. The passage is as follows.\n\n     \"I may take this opportunity of remarking that my critics\n     frequently assume that I attribute all changes of corporeal\n     structure and mental power exclusively to the natural selection of\n     such variations as are often called spontaneous; whereas, even in\n     the first edition of the 'Origin of Species,' I distinctly stated\n     that great weight must be attributed to the inherited effects of\n     use and disuse, with respect both to the body and mind.\"\n\nNor is this all. There is evidence that Mr. Darwin's belief in the\nefficiency of this factor, became stronger as he grew older and\naccumulated more evidence. The first of the extracts above given, taken\nfrom the sixth edition of the _Origin of Species_, runs thus:--\n\n     \"I think there can be no doubt that use in our domestic animals has\n     strengthened and enlarged certain parts, and disuse diminished\n     them; and that such modifications are inherited.\"\n\nNow on turning to the first edition, p. 134, it will be found that\ninstead of the words--\"I think there can be no doubt,\" the words\noriginally used were--\"I think there can be _little_ doubt.\" That this\ndeliberate erasure of a qualifying word and substitution of a word\nimplying unqualified belief, was due to a more decided recognition of a\nfactor originally under-estimated, is clearly implied by the wording of\nthe above-quoted passage from the preface to the _Descent of Man_; where\nhe says that \"_even_ in the first edition of the 'Origin of Species,'\"\n&c.: the implication being that much more in subsequent editions, and\nsubsequent works, had he insisted on this factor. The change thus\nindicated is especially significant as having occurred at a time of life\nwhen the natural tendency is towards fixity of opinion.\n\nDuring that earlier period when he was discovering the multitudinous\ncases in which his own hypothesis afforded solutions, and simultaneously\nobserving how utterly futile in these multitudinous cases was the\nhypothesis propounded by his grandfather and Lamarck, Mr. Darwin was,\nnot unnaturally, almost betrayed into the belief that the one is\nall-sufficient and the other inoperative. But in the mind of one so\ncandid and ever open to more evidence, there naturally came a reaction.\nThe inheritance of functionally-produced modifications, which, judging\nby the passage quoted above concerning the views of these earlier\nenquirers, would seem to have been at one time denied, but which as we\nhave seen was always to some extent recognized, came to be recognized\nmore and more, and deliberately included as a factor of importance.\n\n       *       *       *       *       *\n\nOf this reaction displayed in the later writings of Mr. Darwin, let us\nnow ask--Has it not to be carried further? Was the share in organic\nevolution which Mr. Darwin latterly assigned to the transmission of\nmodifications caused by use and disuse, its due share? Consideration of\nthe groups of evidences given above, will, I think, lead us to believe\nthat its share has been much larger than he supposed even in his later\ndays.\n\nThere is first the implication yielded by extensive classes of phenomena\nwhich remain inexplicable in the absence of this factor. If, as we see,\nco-operative parts do not vary together, even when few and close\ntogether, and may not therefore be assumed to do so when many and\nremote, we cannot account for those innumerable changes in organization\nwhich are implied when, for advantageous use of some modified part, many\nother parts which join it in action have to be modified.\n\nFurther, as increasing complexity of structure, accompanying increasing\ncomplexity of life, implies increasing number of faculties, of which\neach one conduces to preservation of self or descendants; and as the\nvarious individuals of a species, severally requiring something like the\nnormal amounts of all these, may individually profit, here by an unusual\namount of one, and there by an unusual amount of another; it follows\nthat as the number of faculties becomes greater, it becomes more\ndifficult for any one to be further developed by natural selection. Only\nwhere increase of some one is _predominantly_ advantageous does the\nmeans seem adequate to the end. Especially in the case of powers which\ndo not subserve self-preservation in appreciable degrees, does\ndevelopment by natural selection appear impracticable.\n\nIt is a fact recognized by Mr. Darwin, that where, by selection through\nsuccessive generations, a part has been increased or decreased, its\nreaction upon other parts entails changes in them. This reaction is\neffected through the changes of function involved. If the changes of\nstructure produced by such changes of function, are inheritable, then\nthe re-adjustment of parts throughout the organism, taking place\ngeneration after generation, maintains an approximate balance; but if\nnot, then generation after generation the organism must get more and\nmore out of gear, and tend to become unworkable.\n\nFurther, as it is proved that change in the balance of functions\nregisters its effects on the reproductive elements, we have to choose\nbetween the alternatives that the registered effects are irrelevant to\nthe particular modifications which the organism has undergone, or that\nthey are such as tend to produce repetitions of these modifications. The\nlast of these alternatives makes the facts comprehensible; but the first\nof them not only leaves us with several unsolved problems, but is\nincongruous with the general truth that by reproduction, ancestral\ntraits, down to minute details, are transmitted.\n\nThough, in the absence of pecuniary interests and the interests in\nhobbies, no such special experiments as those which have established the\ninheritance of fortuitous variations have been made to ascertain whether\nfunctionally-produced modifications are inherited; yet certain apparent\ninstances of such inheritance have forced themselves on observation\nwithout being sought for. In addition to other indications of a less\nconspicuous kind, is the one I have given above--the fact that the\napparatus for tearing and mastication has decreased with decrease of its\nfunction, alike in civilized man and in some varieties of dogs which\nlead protected and pampered lives. Of the numerous cases named by Mr.\nDarwin, it is observable that they are yielded not by one class of parts\nonly, but by most if not all classes--by the dermal system, the muscular\nsystem, the osseous system, the nervous system, the viscera; and that\namong parts liable to be functionally modified, the most numerous\nobserved cases of inheritance are furnished by those which admit of\npreservation and easy comparison--the bones: these cases, moreover,\nbeing specially significant as showing how, in sundry unallied species,\nparallel changes of structure have occurred along with parallel changes\nof habit.\n\nWhat, then, shall we say of the general implication? Are we to stop\nshort with the admission that inheritance of functionally-produced\nmodifications takes place only in cases in which there is evidence of\nit? May we properly assume that these many instances of changes of\nstructure caused by changes of function, occurring in various tissues\nand various organs, are merely special and exceptional instances having\nno general significance? Shall we suppose that though the evidence which\nalready exists has come to light without aid from a body of inquirers,\nthere would be no great increase were due attention devoted to the\ncollection of evidence? This is, I think, not a reasonable supposition.\nTo me the _ensemble_ of the facts suggests the belief, scarcely to be\nresisted, that the inheritance of functionally-produced modifications\ntakes place universally. Looking at physiological phenomena as\nconforming to physical principles, it is difficult to conceive that a\nchanged play of organic forces which in many cases of different kinds\nproduces an inherited change of structure, does not do this in all\ncases. The implication, very strong I think, is that the action of every\norgan produces on it a reaction which, usually not altering its rate of\nnutrition, sometimes leaves it with diminished nutrition consequent on\ndiminished action, and at other times increases its nutrition in\nproportion to its increased action; that while generating a modified\n_consensus_ of functions and of structures, the activities are at the\nsame time impressing this modified _consensus_ on the sperm-cells and\ngerm-cells whence future individuals are to be produced; and that in\nways mostly too small to be identified, but occasionally in more\nconspicuous ways and in the course of generations, the resulting\nmodifications of one or other kind show themselves. Further, it seems to\nme that as there are certain extensive classes of phenomena which are\ninexplicable if we assume the inheritance of fortuitous variations to be\nthe sole factor, but which become at once explicable if we admit the\ninheritance of functionally-produced changes, we are justified in\nconcluding that this inheritance of functionally-produced changes has\nbeen not simply a co-operating factor in organic evolution, but has been\na co-operating factor without which organic evolution, in its higher\nforms at any rate, could never have taken place.\n\nBe this or be it not a warrantable conclusion, there is, I think, good\nreason for a provisional acceptance of the hypothesis that the effects\nof use and disuse are inheritable; and for a methodic pursuit of\ninquiries with the view of either establishing it or disproving it. It\nseems scarcely reasonable to accept without clear demonstration, the\nbelief that while a trivial difference of structure arising\nspontaneously is transmissible, a massive difference of structure,\nmaintained generation after generation by change of function, leaves no\ntrace in posterity. Considering that unquestionably the modification of\nstructure by function is a _vera causa_, in so far as concerns the\nindividual; and considering the number of facts which so competent an\nobserver as Mr. Darwin regarded as evidence that transmission of such\nmodifications takes place in particular cases; the hypothesis that such\ntransmission takes place in conformity with a general law, holding of\nall active structures, should, I think, be regarded as at least a good\nworking hypothesis.\n\n       *       *       *       *       *\n\nBut now supposing the broad conclusion above drawn to be\ngranted--supposing all to agree that from the beginning, along with\ninheritance of useful variations fortuitously arising, there has been\ninheritance of effects produced by use and disuse; do there remain no\nclasses of organic phenomena unaccounted for? To this question I think\nit must be replied that there do remain classes of organic phenomena\nunaccounted for. It may, I believe, be shown that certain cardinal\ntraits of animals and plants at large are still unexplained; and that a\nfurther factor must be recognized. To show this, however, will require\nanother paper.\n\n\nII.\n\nAsk a plumber who is repairing your pump, how the water is raised in it,\nand he replies--\"By suction.\" Recalling the ability which he has to suck\nup water into his mouth through a tube, he is certain that he\nunderstands the pump's action. To inquire what he means by suction,\nseems to him absurd. He says you know as well as he does, what he means;\nand he cannot see that there is any need for asking how it happens that\nthe water rises in the tube when he strains his mouth in a particular\nway. To the question why the pump, acting by suction, will not make the\nwater rise above 32 feet, and practically not so much, he can give no\nanswer; but this does not shake his confidence in his explanation.\n\nOn the other hand an inquirer who insists on knowing what suction is,\nmay obtain from the physicist answers which give him clear ideas, not\nonly about it but about many other things. He learns that on ourselves\nand all things around, there is an atmospheric pressure amounting to\nabout 15 pounds on the square inch: 15 pounds being the average weight\nof a column of air having a square inch for its base and extending\nupwards from the sea-level to the limit of the Earth's atmosphere. He is\nmade to observe that when he puts one end of a tube into water and the\nother end into his mouth, and then draws back his tongue, so leaving a\nvacant space, two things happen. One is that the pressure of air outside\nhis cheeks, no longer balanced by an equal pressure of air inside,\nthrusts his cheeks inwards; and the other is that the pressure of air on\nthe surface of the water, no longer balanced by an equal pressure of air\nwithin the tube and his mouth (into which part of the air from the tube\nhas gone) the water is forced up the tube in consequence of the unequal\npressure. Once understanding thus the nature of the so-called suction,\nhe sees how it happens that when the plunger of the pump is raised and\nrelieves from atmospheric pressure the water below it, the atmospheric\npressure on the water in the well, not being balanced by that on the\nwater in the tube, forces the water higher up the tube, so that it\nfollows the plunger. And now he sees why the water cannot be raised\nbeyond the theoretic limit of 32 feet: a limit made much lower in\npractice by imperfections in the apparatus. For if, simplifying the\nconception, he supposes the tube of the pump to be a square inch in\nsection, then the atmospheric pressure of 15 pounds per square inch on\nthe water in the well, can raise the water in the tube to such height\nonly that the entire column of it weighs 15 pounds. Having been thus\nenlightened about the pump's action, the action of a barometer becomes\nintelligible. He perceives how, under the conditions established, the\nweight of the column of mercury balances that of an atmospheric column\nof equal diameter; and how, as the weight of the atmospheric column\nvaries, there is a corresponding variation in the weight of the\nmercurial column,--shown by change of height. Moreover, having\npreviously supposed that he understood the ascent of a balloon when he\nascribed it to relative lightness, he now sees that he did not truly\nunderstand it. For he did not recognize it as a result of that upward\npressure caused by the difference between the weight of the mass formed\nby the gas in the balloon _plus_ the cylindrical column of air extending\nabove it to the limit of the atmosphere, and the weight of a similar\ncylindrical column of air extending down to the under surface of the\nballoon: this difference of weight causing an equivalent upward pressure\non the under surface.\n\nWhy do I introduce these familiar truths so entirely irrelevant to my\nsubject? I do it to show, in the first place, the contrast between a\nvague conception of a cause and a distinct conception of it; or rather,\nthe contrast between that conception of a cause which results when it is\nsimply classed with some other or others which familiarity makes us\nthink we understand, and that conception of a cause which results when\nit is represented in terms of definite physical forces admitting of\nmeasurement. And I do it to show, in the second place, that when we\ninsist on resolving a verbally-intelligible cause into its actual\nfactors, we get not only a clear solution of the problem before us, but\nwe find that the way is opened to solutions of sundry other problems.\nWhile we rest satisfied with unanalyzed causes, we may be sure both that\nwe do not rightly comprehend the production of the particular effects\nascribed to them, and that we overlook other effects which would be\nrevealed to us by contemplation of the causes as analyzed. Especially\nmust this be so where the causation is complex. Hence we may infer that\nthe phenomena presented by the development of species, are not likely to\nbe truly conceived unless we keep in view the concrete agencies at work.\nLet us look closely at the facts to be dealt with.\n\n       *       *       *       *       *\n\nThe growth of a thing is effected by the joint operation of certain\nforces on certain materials; and when it dwindles, there is either a\nlack of some materials, or the forces co-operate in a way different from\nthat which produces growth. If a structure has varied, the implication\nis that the processes which built it up were made unlike the parallel\nprocesses in other cases, by the greater or less amount of some one or\nmore of the matters or actions concerned. Where there is unusual\nfertility, the play of vital activities is thereby shown to have\ndeviated from the ordinary play of vital activities; and conversely, if\nthere is infertility. If the germs, or ova, or seed, or offspring\npartially developed, survive more or survive less, it is either because\ntheir molar or molecular structures are unlike the average ones, or\nbecause they are affected in unlike ways by surrounding agencies. When\nlife is prolonged, the fact implies that the combination of actions,\nvisible and invisible, constituting life, retains its equilibrium longer\nthan usual in presence of environing forces which tend to destroy its\nequilibrium. That is to say, growth, variation, survival, death, if they\nare to be reduced to the forms in which physical science can recognize\nthem, must be expressed as effects of agencies definitely\nconceived--mechanical forces, light, heat, chemical affinity, &c.\n\nThis general conclusion brings with it the thought that the phrases\nemployed in discussing organic evolution, though convenient and indeed\nneedful, are liable to mislead us by veiling the actual agencies. That\nwhich really goes on in every organism is the working together of\ncomponent parts in ways conducing to the continuance of their combined\nactions, in presence of things and actions outside; some of which tend\nto subserve, and others to destroy, the combination. The matters and\nforces in these two groups, are the sole causes properly so called. The\nwords \"natural selection,\" do not express a cause in the physical sense.\nThey express a mode of co-operation among causes--or rather, to speak\nstrictly, they express an effect of this mode of co-operation. The idea\nthey convey seems perfectly intelligible. Natural selection having been\ncompared with artificial selection, and the analogy pointed out, there\napparently remains no indefiniteness: the inconvenience being, however,\nthat the definiteness is of a wrong kind. The tacitly implied Nature\nwhich selects, is not an embodied agency analogous to the man who\nselects artificially; and the selection is not the picking out of an\nindividual fixed on, but the overthrowing of many individuals by\nagencies which one successfully resists, and hence continues to live and\nmultiply. Mr. Darwin was conscious of these misleading implications. In\nthe introduction to his _Animals and Plants under Domestication_ (p. 6)\nhe says:--\n\n     \"For brevity sake I sometimes speak of natural selection as an\n     intelligent power; ... I have, also, often personified the word\n     Nature; for I have found it difficult to avoid this ambiguity; but\n     I mean by nature only the aggregate action and product of many\n     natural laws,--and by laws only the ascertained sequence of\n     events.\"\n\nBut while he thus clearly saw, and distinctly asserted, that the factors\nof organic evolution are the concrete actions, inner and outer, to which\nevery organism is subject, Mr. Darwin, by habitually using the\nconvenient figure of speech, was, I think, prevented from recognizing so\nfully as he would otherwise have done, certain fundamental consequences\nof these actions.\n\nThough it does not personalize the cause, and does not assimilate its\nmode of working to a human mode of working, kindred objections may be\nurged against the expression to which I was led when seeking to present\nthe phenomena in literal terms rather than metaphorical terms--the\nsurvival of the fittest;[42] for in a vague way the first word, and in a\nclear way the second word, calls up an anthropocentric idea. The\nthought of survival inevitably suggests the human view of certain sets\nof phenomena, rather than that character which they have simply as\ngroups of changes. If, asking what we really know of a plant, we exclude\nall the ideas associated with the words life and death, we find that the\nsole facts known to us are that there go on in the plant certain\ninter-dependent processes, in presence of certain aiding and hindering\ninfluences outside of it; and that in some cases a difference of\nstructure or a favourable set of circumstances, allows these\ninter-dependent processes to go on for longer periods than in other\ncases. Again, in the working together of those many actions, internal\nand external, which determine the lives or deaths of organisms, we see\nnothing to which the words fitness and unfitness are applicable in the\nphysical sense. If a key fits a lock, or a glove a hand, the relation of\nthe things to one another is presentable to the perceptions. No approach\nto fitness of this kind is made by an organism which continues to live\nunder certain conditions. Neither the organic structures themselves, nor\ntheir individual movements, nor those combined movements of certain\namong them which constitute conduct, are related in any analogous way to\nthe things and actions in the environment. Evidently the word fittest,\nas thus used, is a figure of speech; suggesting the fact that amid\nsurrounding actions, an organism characterized by the word has either a\ngreater ability than others of its kind to maintain the equilibrium of\nits vital activities, or else has so much greater a power of\nmultiplication that though not longer lived than they, it continues to\nlive in posterity more persistently. And indeed, as we here see, the\nword fittest has to cover cases in which there may be less ability than\nusual to survive individually, but in which the defect is more than made\ngood by higher degrees of fertility.\n\nI have elaborated this criticism with the intention of emphasizing the\nneed for studying the changes which have gone on, and are ever going\non, in organic bodies, from an exclusively physical point of view. On\ncontemplating the facts from this point of view, we become aware that,\nbesides those special effects of the co-operating forces which eventuate\nin the longer survival of one individual than of others, and in the\nconsequent increase through generations, of some trait which furthered\nits survival, many other effects are being wrought on each and all of\nthe individuals. Bodies of every class and quality, inorganic as well as\norganic, are from instant to instant subject to the influences in their\nenvironments; are from instant to instant being changed by these in ways\nthat are mostly inconspicuous; and are in course of time changed by them\nin conspicuous ways. Living things in common with dead things, are, I\nsay, being thus perpetually acted upon and modified; and the changes\nhence resulting, constitute an all-important part of those undergone in\nthe course of organic evolution. I do not mean to imply that changes of\nthis class pass entirely unrecognized; for, as we shall see, Mr. Darwin\ntakes cognizance of certain secondary and special ones. But the effects\nwhich are not taken into account, are those primary and universal\neffects which give certain fundamental characters to all organisms.\nContemplation of an analogy will best prepare the way for appreciation\nof them, and of the relation they bear to those which at present\nmonopolize attention.\n\nAn observant rambler along shores, will, here and there, note places\nwhere the sea has deposited things more or less similar, and separated\nthem from dissimilar things--will see shingle parted from sand; larger\nstones sorted from smaller stones; and will occasionally discover\ndeposits of shells more or less worn by being rolled about. Sometimes\nthe pebbles or boulders composing the shingle at one end of a bay, he\nwill find much larger than those at the other: intermediate sizes,\nhaving small average differences, occupying the space between the\nextremes. An example occurs, if I remember rightly, some mile or two to\nthe west of Tenby; but the most remarkable and well-known example is\nthat afforded by the Chesil bank. Here, along a shore some sixteen miles\nlong, there is a gradual increase in the sizes of the stones; which,\nbeing at one end but mere pebbles, are at the other end immense\nboulders. In this case, then, the breakers and the undertow have\neffected a selection--have at each place left behind those stones which\nwere too large to be readily moved, while taking away others small\nenough to be moved easily. But now, if we contemplate exclusively this\nselective action of the sea, we overlook certain important effects which\nthe sea simultaneously works. While the stones have been differently\nacted upon in so far that some have been left here and some carried\nthere; they have been similarly acted upon in two allied, but\ndistinguishable, ways. By perpetually rolling them about and knocking\nthem one against another, the waves have so broken off their most\nprominent parts as to produce in all of them more or less rounded forms;\nand then, further, the mutual friction of the stones simultaneously\ncaused, has smoothed their surfaces. That is to say in general terms,\nthe actions of environing agencies, so far as they have operated\nindiscriminately, have produced in the stones a certain unity of\ncharacter; at the same time that they have, by their differential\neffects, separated them: the larger ones having withstood certain\nviolent actions which the smaller ones could not withstand.\n\nSimilarly with other assemblages of objects which are alike in their\nprimary traits but unlike in their secondary traits. When simultaneously\nexposed to the same set of actions, some of these actions, rising to a\ncertain intensity, may be expected to work on particular members of the\nassemblage changes which they cannot work in those which are markedly\nunlike; while others of the actions will work in all of them similar\nchanges, because of the uniform relations between these actions and\ncertain attributes common to all members of the assemblage. Hence it is\ninferable that on living organisms, which form an assemblage of this\nkind, and are unceasingly exposed in common to the agencies composing\ntheir inorganic environments, there must be wrought two such sets of\neffects. There will result a universal likeness among them consequent on\nthe likeness of their respective relations to the matters and forces\naround; and there will result, in some cases, the differences due to the\ndifferential effects of these matters and forces, and in other cases,\nthe changes which, being life-sustaining or life-destroying, eventuate\nin certain natural selections.\n\nI have, above, made a passing reference to the fact that Mr. Darwin did\nnot fail to take account of some among these effects directly produced\non organisms by surrounding inorganic agencies. Here are extracts from\nthe sixth edition of the _Origin of Species_ showing this.\n\n     \"It is very difficult to decide how far changed conditions, such as\n     of climate, food, &c., have acted in a definite manner. There is\n     reason to believe that in the course of time the effects have been\n     greater than can be proved by clear evidence.... Mr. Gould believes\n     that birds of the same species are more brightly coloured under a\n     clear atmosphere, than when living near the coast or on islands;\n     and Wollaston is convinced that residence near the sea affects the\n     colours of insects. Moquin-Tandon gives a list of plants which,\n     when growing near the sea-shore, have their leaves in some degree\n     fleshy, though not elsewhere fleshy\" (pp. 106-7). \"Some observers\n     are convinced that a damp climate affects the growth of the hair,\n     and that with the hair the horns are correlated\" (p. 159).\n\nIn his subsequent work, _Animals and Plants under Domestication_, Mr.\nDarwin still more clearly recognizes these causes of change in\norganization. A chapter is devoted to the subject. After premising that\n\"the direct action of the conditions of life, whether leading to\ndefinite or indefinite results, is a totally distinct consideration from\nthe effects of natural selection;\" he goes on to say that changed\nconditions of life \"have acted so definitely and powerfully on the\norganisation of our domesticated productions, that they have sufficed\nto form new sub-varieties or races, without the aid of selection by man\nor of natural selection.\" Of his examples here are two.\n\n     \"I have given in detail in the ninth chapter the most remarkable\n     case known to me, namely, that in Germany several varieties of\n     maize brought from the hotter parts of America were transformed in\n     the course of only two or three generations.\" (Vol. ii, p. 277.)\n     [And in this ninth chapter concerning these and other such\n     instances he says \"some of the foregoing differences would\n     certainly be considered of specific value with plants in a state of\n     nature.\" (Vol. i, p. 321.)] \"Mr. Meehan, in a remarkable paper,\n     compares twenty-nine kinds of American trees, belonging to various\n     orders, with their nearest European allies, all grown in close\n     proximity in the same garden and under as nearly as possible the\n     same conditions.\" And then enumerating six traits in which the\n     American forms all of them differ in like ways from their allied\n     European forms, Mr. Darwin thinks there is no choice but to\n     conclude that these \"have been definitely caused by the\n     long-continued action of the different climate of the two\n     continents on the trees.\" (Vol. ii, pp. 281-2.)\n\nBut the fact we have to note is that while Mr. Darwin thus took account\nof special effects due to special amounts and combinations of agencies\nin the environment, he did not take account of the far more important\neffects due to the general and constant operation of these agencies.[43]\nIf a difference between the quantities of a force which acts on two\norganisms, otherwise alike and otherwise similarly conditioned, produces\nsome difference between them; then, by implication, this force produces\nin both of them effects which they show in common. The inequality\nbetween two things cannot have a value unless the things themselves have\nvalues. Similarly if, in two cases, some unlikeness of proportion among\nthe surrounding inorganic agencies to which two plants or two animals\nare exposed, is followed by some unlikeness in the changes wrought on\nthem; then it follows that these several agencies taken separately, work\nchanges in both of them. Hence we must infer that organisms have certain\nstructural characters in common, which are consequent on the action of\nthe medium in which they exist: using the word medium in a comprehensive\nsense, as including all physical forces falling upon them as well as\nmatters bathing them. And we may conclude that from the primary\ncharacters thus produced there must result secondary characters.\n\nBefore going on to observe those general traits of organisms due to the\ngeneral action of the inorganic environment upon them, I feel tempted to\nenlarge on the effects produced by each of the several matters and\nforces constituting the environment. I should like to do this not only\nto give a clear preliminary conception of the ways in which all\norganisms are affected by these universally-present agents, but also to\nshow that, in the first place, these agents modify inorganic bodies as\nwell as organic bodies, and that, in the second place, the organic are\nfar more modifiable by them than the inorganic. But to avoid undue\nsuspension of the argument, I content myself with saying that when the\nrespective effects of gravitation, heat, light, &c., are studied, as\nwell as the respective effects, physical and chemical, of the matters\nforming the media, water and air, it will be found that while more or\nless operative on all bodies, each modifies organic bodies to an extent\nimmensely greater than the extent to which it modifies inorganic bodies.\n\n       *       *       *       *       *\n\nHere, not discriminating among the special effects which these various\nforces and matters in the environment produce on both classes of bodies,\nlet us consider their combined effects, and ask--What is the most\ngeneral trait of such effects?\n\nObviously the most general trait is the greater amount of change wrought\non the outer surface than on the inner mass. In so far as the matters of\nwhich the medium is composed come into play, the unavoidable implication\nis that they act more on the parts directly exposed to them than on the\nparts sheltered from them. And in so far as the forces pervading the\nmedium come into play, it is manifest that, excluding gravity, which\naffects outer and inner parts indiscriminately, the outer parts have to\nbear larger shares of their actions. If it is a question of heat, then\nthe exterior must lose it or gain it faster than the interior; and in a\nmedium which is now warmer and now colder, the two must habitually\ndiffer in temperature to some extent--at least where the size is\nconsiderable. If it is a question of light, then in all but absolutely\ntransparent masses, the outer parts must undergo more of any change\nproducible by it than the inner parts--supposing other things equal; by\nwhich I mean, supposing the case is not complicated by any such\nconvexities of the outer surface as produce internal concentrations of\nrays. Hence then, speaking generally, the necessity is that the primary\nand almost universal effect of the converse between the body and its\nmedium, is to differentiate its outside from its inside. I say almost\nuniversal, because where the body is both mechanically and chemically\nstable, like, for instance, a quartz crystal, the medium may fail to\nwork either inner or outer change.\n\nOf illustrations among inorganic bodies, a convenient one is supplied by\nan old cannon-ball that has been long lying exposed. A coating of rust,\nformed of flakes within flakes, incloses it; and this thickens year by\nyear, until, perhaps, it reaches a stage at which its exterior loses as\nmuch by rain and wind as its interior gains by further oxidation of the\niron. Most mineral masses--pebbles, boulders, rocks--if they show any\neffect of the environment at all, show it only by that disintegration of\nsurface which follows the freezing of absorbed water: an effect which,\nthough mechanical rather than chemical, equally illustrates the general\ntruth. Occasionally a \"rocking-stone\" is thus produced. There are formed\nsuccessive layers relatively friable in texture, each of which, thickest\nat the most exposed parts, and being presently lost by weathering,\nleaves the contained mass in a shape more rounded than before; until,\nresting on its convex under-surface, it is easily moved. But of all\ninstances perhaps the most remarkable is one to be seen on the west bank\nof the Nile at Philae, where a ridge of granite 100 feet high, has had\nits outer parts reduced in course of time to a collection of\nboulder-shaped masses, varying from say a yard in diameter to six or\neight feet, each one of which shows in progress an exfoliation of\nsuccessively-formed shells of decomposed granite: most of the masses\nhaving portions of such shells partially detached.\n\nIf, now, inorganic masses, relatively so stable in composition, thus\nhave their outer parts differentiated from their inner parts, what must\nwe say of organic masses, characterized by such extreme chemical\ninstability?--instability so great that their essential material is\nnamed protein, to indicate the readiness with which it passes from one\nisomeric form to another. Clearly the necessary inference is that this\neffect of the medium must be wrought inevitably and promptly, wherever\nthe relation of outer and inner has become settled: a qualification for\nwhich the need will be seen hereafter.\n\n       *       *       *       *       *\n\nBeginning with the earliest and most minute kinds of living things, we\nnecessarily encounter difficulties in getting direct evidence; since, of\nthe countless species now existing, all have been subject during\nmillions upon millions of years to the evolutionary process, and have\nhad their primary traits complicated and obscured by those endless\nsecondary traits which the natural selection of favourable variations\nhas produced. Among protophytes it needs but to think of the\nmultitudinous varieties of diatoms and desmids, with their\nelaborately-constructed coverings; or of the definite methods of growth\nand multiplication among such simple _Algae_ as the _Conjugatae_; to see\nthat most of their distinctive characters are due to inherited\nconstitutions, which have been slowly moulded by survival of the fittest\nto this or that mode of life. To disentangle such parts of their\ndevelopmental changes as are due to the action of the medium, is\ntherefore hardly possible. We can hope only to get a general conception\nof it by contemplating the totality of the facts.\n\nThe first cardinal fact is that all protophytes are cellular--all show\nus this contrast between outside and inside. Supposing the multitudinous\nspecialities of the envelope in different orders and genera of\nprotophytes to be set against one another, and mutually cancelled, there\nremains as a trait common to them--an envelope unlike that which it\nenvelopes. The second cardinal fact is that this simple trait is the\nearliest trait displayed in germs, or spores, or other parts from which\nnew individuals are to arise; and that, consequently, this trait must be\nregarded as having been primordial. For it is an established truth of\norganic evolution that embryos show us, in general ways, the forms of\nremote ancestors; and that the first changes undergone, indicate, more\nor less clearly, the first changes which took place in the series of\nforms through which the existing form has been reached. Describing, in\nsuccessive groups of plants, the early transformations of these\nprimitive units, Sachs[44] says of the lowest _Algae_ that \"the\nconjugated protoplasmic body clothes itself with a cell-wall\" (p. 10);\nthat in \"the spores of Mosses and Vascular Cryptogams\" and in \"the\npollen of Phanerogams\" ... \"the protoplasmic body of the mother-cell\nbreaks up into four lumps, which quickly round themselves off and\ncontract, and become enveloped by a cell-membrane only after complete\nseparation\" (p. 13); that in the _Equisetaceae_ \"the young spores, when\nfirst separated, are still naked, but they soon become surrounded by a\ncell-membrane\" (p. 14); and that in higher plants, as in the pollen of\nmany Dicotyledons, \"the contracting daughter-cells secrete cellulose\neven during their separation\" (p. 14). Here, then, in whatever way we\ninterpret it, the fact is that there quickly arises an outer layer\ndifferent from the contained matter. But the most significant evidence\nis furnished by \"the masses of protoplasm that escape into water from\nthe injured sacs of _Vaucheria_, which often instantly become rounded\ninto globular bodies,\" and of which the \"hyaline protoplasm envelopes\nthe whole as a skin\" (p. 41) which \"is denser than the inner and more\nwatery substance\" (p. 42). As in this case the protoplasm is but a\nfragment, and as it is removed from the influence of the parent-cell,\nthis differentiating process can scarcely be regarded as anything more\nthan the effect of physico-chemical actions: a conclusion which is\nsupported by the statement of Sachs that \"not only every vacuole in a\nsolid protoplasmic body, but also every thread of protoplasm which\npenetrates the sap-cavity, and finally the inner side of the\nprotoplasm-sac which encloses the sap-cavity, is also bounded by a skin\"\n(p. 42). If then \"every portion of a protoplasmic body immediately\nsurrounds itself, when it becomes isolated, with such a skin,\" which is\nshown in all cases to arise at the surface of contact with sap or water,\nthis primary differentiation of outer from inner must be ascribed to the\ndirect action of the medium. Whether the coating thus initiated is\nsecreted by the protoplasm, or whether, as seems more likely, it\nresults from transformation of it, matters not to the argument. Either\nway the action of the medium causes its formation; and either way the\nmany varied and complex differentiations which developed cell-walls\ndisplay, must be considered as originating from those variations of this\nphysically-generated covering which natural selection has taken\nadvantage of.\n\nThe contained protoplasm of a vegetal cell, which has self-mobility and\nwhen liberated sometimes performs amoeba-like motions for a time, may\nbe regarded as an imprisoned amoeba; and when we pass from it to a\nfree amoeba, which is one of the simplest types of first animals, or\n_Protozoa_, we naturally meet with kindred phenomena. The general trait\nwhich here concerns us, is that while its plastic or semi-fluid sarcode\ngoes on protruding, in irregular ways, now this and now that part of its\nperiphery, and again withdrawing into its interior first one and then\nanother of these temporary processes, perhaps with some small portion of\nfood attached, there is but an indistinct differentiation of outer from\ninner (a fact shown by the frequent coalescence of the pseudopodia in\nRhizopods); but that when it eventually becomes quiescent, the surface\nbecomes differentiated from the contents: the passing into an encysted\nstate, doubtless in large measure due to inherited proclivity, being\nfurthered, and having probably been once initiated, by the action of the\nmedium. The connexion between constancy of relative position among the\nparts of the sarcode, and the rise of a contrast between superficial and\ncentral parts, is perhaps best shown in the minutest and simplest\n_Infusoria_, the _Monadinae_. The genus _Monas_ is described by Kent as\n\"plastic and unstable in form, possessing no distinct cuticular\ninvestment; ... the food-substances incepted at all parts of the\nperiphery\";[45] and the genus _Scytomonas_ he says \"differs from _Monas_\nonly in its persistent shape and accompanying greater rigidity of the\nperipheral or ectoplasmic layer.\"[46] Describing generally such low\nforms, some of which are said to have neither nucleus nor vacuole, he\nremarks that in types somewhat higher \"the outer or peripheral border of\nthe protoplasmic mass, while not assuming the character of a distinct\ncell-wall or so-called cuticle, presents, as compared with the inner\nsubstance of that mass, a slightly more solid type of composition.\"[47]\nAnd it is added that these forms having so slightly differentiated an\nexterior, \"while usually exhibiting a more or less characteristic normal\noutline, can revert at will to a pseud-amoeboid and repent state.\"[48]\nHere, then, we have several indications of the truth that the permanent\nexternality of a certain part of the substance, is followed by\ntransformation of it into a coating unlike the substance it contains.\nIndefinite and structureless in the simplest of these forms, as instance\nagain the _Gregarina_,[49] the limiting membrane becomes, in higher\n_Infusoria_, definite and often complex: showing that the selection of\nfavourable variations has had largely to do with its formation. In such\ntypes as the _Foraminifera_, which, almost structureless internally\nthough they are, secrete calcareous shells, it is clear that the nature\nof this outer layer is determined by inherited constitution. But\nrecognition of this consists with the belief that the action of the\nmedium initiated the outer layer, specialized though it now is; and that\neven still, contact with the medium excites secretion of it.\n\nA remarkable analogy remains to be named. When we study the action of\nthe medium in an inorganic mass, we are led to see that between the\nouter changed layer and the inner unchanged mass, comes a surface where\nactive change is going on. Here we have to note that, alike in the\nplant-cell and in the animal-cell, there is a similar relation of parts.\nImmediately inside the envelope comes the primordial utricle in the\none case, and in the other case the layer of active sarcode. In either\ncase the living protoplasm, placed in the position of a lining to the\ncuticle of the cell, is shielded from the direct action of the medium,\nand yet is not beyond the reach of its influences.\n\n       *       *       *       *       *\n\nLimited, as thus far drawn, to a certain common trait of those minute\norganisms which are mostly below the reach of unaided vision, the\nforegoing conclusion appears trivial enough. But it ceases to appear\ntrivial on passing into a wider field, and observing the implications,\ndirect and indirect, as they concern plants and animals of sensible\nsizes.\n\nPopular expositions of science have so far familiarized many readers\nwith a certain fundamental trait of living things around, that they have\nceased to perceive how marvellous a trait it is, and, until interpreted\nby the Theory of Evolution, how utterly mysterious. In past times, the\nconception of an ordinary plant or animal which prevailed, not\nthroughout the world at large only but among the most instructed, was\nthat it is a single continuous entity. One of these livings things was\nunhesitatingly regarded as being in all respects a unit. Parts it might\nhave, various in their sizes, forms, and compositions; but these were\ncomponents of a whole which had been from the beginning in its original\nnature a whole. Even to naturalists fifty years ago, the assertion that\na cabbage or a cow, though in one sense a whole, is in another sense a\nvast society of minute individuals, severally living in greater or less\ndegrees, and some of them maintaining their independent lives\nunrestrained, would have seemed an absurdity. But this truth which, like\nso many of the truths established by science, is contrary to that common\nsense in which most people have so much confidence, has been gradually\ngrowing clear since the days when Leeuwenhoeck and his contemporaries\nbegan to examine through lenses the minute structures of common plants\nand animals. Each improvement in the microscope, while it has widened\nour knowledge of those minute forms of life described above, has\nrevealed further evidence of the fact that all the larger forms of life\nconsist of units severally allied in their fundamental traits to these\nminute forms of life. Though, as formulated by Schwann and Schleiden,\nthe cell-doctrine has undergone qualifications of statement; yet the\nqualifications have not been such as to militate against the general\nproposition that organisms visible to the naked eye, are severally\ncompounded of invisible organisms--using that word in its most\ncomprehensive sense. And then, when the development of any animal is\ntraced, it is found that having been primarily a nucleated cell, and\nhaving afterwards become by spontaneous fission a cluster of nucleated\ncells, it goes on through successive stages to form out of such cells,\never multiplying and modifying in various ways, the several tissues and\norgans composing the adult.\n\nOn the hypothesis of evolution this universal trait has to be accepted\nnot as a fact that is strange but unmeaning. It has to be accepted as\nevidence that all the visible forms of life have arisen by union of the\ninvisible forms; which, instead of flying apart when they divided,\nremained together. Various intermediate stages are known. Among plants,\nthose of the _Volvox_ type show us the component protophytes so feebly\ncombined that they severally carry on their lives with no appreciable\nsubordination to the life of the group. And among animals, a parallel\nrelation between the lives of the units and the life of the group is\nshown us in _Uroglena_ and _Syncrypta_. From these first stages upwards,\nmay be traced through successively higher types, an increasing\nsubordination of the units to the aggregate; though still a\nsubordination leaving to them conspicuous amounts of individual\nactivity. Joining which facts with the phenomena presented by the\ncell-multiplication and aggregation of every unfolding germ, naturalists\nare now accepting the conclusion that by this process of composition\nfrom _Protozoa_, were formed all classes of the _Metazoa_[50]--(as\nanimals formed by this compounding are now called); and that in a\nsimilar way from _Protophyta_, were formed all classes of what I suppose\nwill be called _Metaphyta_, though the word does not yet seem to have\nbecome current.\n\nAnd now what is the general meaning of these truths, taken in connexion\nwith the conclusion reached in the last section. It is that this\nuniversal trait of the _Metazoa_ and _Metaphyta_, must be ascribed to\nthe primitive action and re-action between the organism and its medium.\nThe operation of those forces which produced the primary differentiation\nof outer from inner in early minute masses of protoplasm, pre-determined\nthis universal cell-structure of all embryos, plant and animal, and the\nconsequent cell-composition of adult forms arising from them. How\nunavoidable is this implication, will be seen on carrying further an\nillustration already used--that of the shingle-covered shore, the\npebbles on which, while being in some cases selected, have been in all\ncases rounded and smoothed. Suppose a bed of such shingle to be, as we\noften see it, solidified, along with interfused material, into a\nconglomerate. What in such case must be considered as the chief trait of\nsuch conglomerate; or rather--what must we regard as the chief cause of\nits distinctive characters? Evidently the action of the sea. Without the\nbreakers, no pebbles; without the pebbles, no conglomerate. Similarly\nthen, in the absence of that action of the medium by which was effected\nthe differentiation of outer from inner in those microscopic portions of\nprotoplasm constituting the earliest and simplest animals and plants,\nthere could not have existed this cardinal trait of composition which\nall the higher animals and plants show us.\n\nSo that, active as has been the part played by natural selection, alike\nin modifying and moulding the original units--largely as survival of\nthe fittest has been instrumental in furthering and controlling the\ncombination of these units into visible organisms, and eventually into\nlarge ones; yet we must ascribe to the direct effect of the medium\non the first forms of life, that character of which this\neverywhere-operative factor has taken advantage.\n\n       *       *       *       *       *\n\nLet us turn now to another and more obvious attribute of higher\norganisms, for which also there is this same general cause. Let us\nobserve how, on a higher platform, there recurs this differentiation of\nouter from inner--how this primary trait in the living units with which\nlife commences, re-appears as a primary trait in those aggregates of\nsuch units which constitute visible organisms.\n\nIn its simplest and most unmistakable form, we see this in the early\nchanges of an unfolding ovum of primitive type. The original fertilized\nsingle cell, having by spontaneous fission multiplied into a cluster of\nsuch cells, there begins to show itself a contrast between periphery and\ncentre; and presently there is formed a sphere consisting of a\nsuperficial layer unlike its contents. The first change, then, is the\nrise of a difference between that outer part which holds direct converse\nwith the surrounding medium, and that inclosed part which does not. This\nprimary differentiation in these compound embryos of higher animals,\nparallels the primary differentiation undergone by the simplest living\nthings.\n\nLeaving, for the present, succeeding changes of the compound embryo, the\nsignificance of which we shall have to consider by-and-by, let us pass\nnow to the adult forms of visible plants and animals. In them we find\ncardinal traits which, after what we have seen above, will further\nimpress us with the importance of the effects wrought on the organism by\nits medium.\n\nFrom the thallus of a sea-weed up to the leaf of a highly developed\nphaenogam, we find, at all stages, a contrast between the inner and\nouter parts of these flattened masses of tissue. In the higher _Algae_\n\"the outermost layers consist of smaller and firmer cells, while the\ninner cells are often very large, and sometimes extremely long;\"[51] and\nin the leaves of trees the epidermal layer, besides differing in the\nsizes and shapes of its component cells from the parenchyma forming the\ninner substance of the leaf, is itself differentiated by having a\ncontinuous cuticle, and by having the outer walls of its cells unlike\nthe inner walls.[52] Especially significant is the structure of such\nintermediate types as the Liverworts. Beyond the differentiation of the\ncovering cells from the contained cells, and the contrast between upper\nsurface and under surface, the frond of _Marchantia polymorpha_ clearly\nshows us the direct effect of incident forces; and shows us, too, how it\nis involved with the effect of inherited proclivities. The frond grows\nfrom a flat disc-shaped gemma, the two sides of which are alike. Either\nside may fall uppermost; and then of the developing shoot, the side\nexposed to the light \"is under all circumstances the upper side which\nforms stomata, the dark side becomes the under side which produces\nroot-hairs and leafy processes.\"[53] So that while we have undeniable\nproof that the contrasted influences of the medium on the two sides,\ninitiate the differentiation, we have also proof that the completion of\nit is determined by the transmitted structure of the type; since it is\nimpossible to ascribe the development of stomata to the direct action of\nair and light. On turning from foliar expansions, to stems and roots,\nfacts of like meaning meet us. Speaking generally of epidermal tissue\nand inner tissue, Sachs remarks that \"the contrast of the two is the\nplainer the more the part of the plant concerned is exposed to air and\nlight.\"[54] Elsewhere, in correspondence with this, it is said that in\nroots the cells of the epidermis, though distinguished by bearing hairs,\n\"are otherwise similar to those of the fundamental tissue\" which they\nclothe,[55] while the cuticular covering is relatively thin; whereas in\nstems the epidermis (often further differentiated) is composed of layers\nof cells which are smaller and thicker-walled: a stronger contrast of\nstructure corresponding to a stronger contrast of conditions. By way of\nmeeting the suggestion that these respective differences are wholly due\nto the natural selection of favourable variations, it will suffice if I\ndraw attention to the unlikeness between imbedded roots and exposed\nroots. While in darkness, and surrounded by moist earth, the outermost\nprotective coats, even of large roots, are comparatively thin; but when\nthe accidents of growth entail permanent exposure to light and air,\nroots acquire coverings allied in character to the coverings of\nbranches. That the action of the medium causes these and converse\nchanges, cannot be doubted when we find, on the one hand, that \"roots\ncan become directly transformed into leaf-bearing shoots,\" and, on the\nother hand, that in some plants certain \"apparent roots are only\nunderground shoots,\" and that nevertheless \"they are similar to true\nroots in function and in the formation of tissue, but have no root-cap,\nand, when they come to the light above ground, continue to grow in the\nmanner of ordinary leaf-shoots.\"[56] If, then, in highly developed\nplants inheriting pronounced structures, this differentiating influence\nof the medium is so marked, it must have been all-important at the\noutset while types were undetermined.\n\nAs with plants so with animals, we find good reason for inferring that\nwhile the specialities of the tegumentary parts must be ascribed to the\nnatural selection of favourable variations, their most general traits\nare due to the direct action of surrounding agencies. Here we come upon\nthe border of those changes which are ascribable to use and disuse. But\nfrom this class of changes we may fitly exclude those in which the parts\nconcerned are wholly or mainly passive. A corn and a blister will\nconveniently serve to illustrate the way in which certain outer actions\ninitiate in the superficial tissues, effects of very marked kinds, which\nare related neither to the needs of the organism nor to its normal\nstructure. They are neither adaptive changes nor changes towards\ncompletion of the type. After noting them we may pass to allied, but\nstill more instructive, changes. Continuous pressure on any portion of\nthe surface causes absorption, while intermittent pressure causes\ngrowth: the one impeding circulation and the passage of plasma from the\ncapillaries into the tissues, and the other aiding both. There are yet\nfurther mechanically-produced effects. That the general character of the\nribbed skin on the under surfaces of the feet and insides of the hands\nis directly due to friction and intermittent pressure, we have the\nproofs:--first, that the tracts most exposed to rough usage are the most\nribbed; second, that the insides of hands subject to unusual amounts of\nrough usage, as those of sailors, are strongly ribbed all over; and\nthird, that in hands which are very little used, the parts commonly\nribbed become quite smooth. These several kinds of evidence, however,\nfull of meaning as they are, I give simply to prepare the way for\nevidence of a much more conclusive kind.\n\nWhere a wide ulcer has eaten away the deep-seated layer out of which the\nepidermis grows, or where this layer has been destroyed by an extensive\nburn, the process of healing is very significant. From the subjacent\ntissues, which in the normal order have no concern with outward growth,\nthere is produced a new skin, or rather a pro-skin; for this substituted\noutward-growing layer contains no hair-follicles or other specialities\nof the original one. Nevertheless, it is like the original one in so far\nthat it is a continually renewed protective covering. Doubtless it may\nbe contended that this make-shift skin results from the inherited\nproclivity of the type--the tendency to complete afresh the structure\nof the species when injured. We cannot, however, ignore the immediate\ninfluence of the medium, on recalling the facts above named, or on\nremembering the further fact that an inflamed surface of skin, when not\nsheltered from the air, will throw out a film of coagulable lymph. But\nthat the direct action of the medium is a chief factor we are clearly\nshown by another case. Accident or disease occasionally causes permanent\neversion, or protrusion, of mucous membrane. After a period of\nirritability, great at first but decreasing as the change advances, this\nmembrane assumes the general character of ordinary skin. Nor is this\nall: its microscopic structure changes. Where it is a mucous membrane of\nthe kind covered by cylinder-epithelium, the cylinders gradually\nshorten, becoming finally flat, and there results a squamous epithelium:\nthere is a near approach in minute composition to epidermis. Here a\ntendency towards completion of the type cannot be alleged; for there is,\ncontrariwise, divergence from the type. The effect of the medium is so\ngreat that, in a short time, it overcomes the inherited proclivity and\nproduces a structure of opposite kind to the normal one.\n\nWith but little break we come here upon a significant analogy, parallel\nto an analogy already described. As was pointed out, an inorganic body\nthat is modifiable by its medium, acquires, after a time, an outer coat\nwhich has already undergone such change as surrounding agencies can\neffect; has a contained mass which is as yet unchanged, because\nunreached; and has a surface between the two where change is going on--a\nregion of activity. And we saw that alike in the vegetal cell and the\nanimal cell there exist analogous distributions: of course with the\ndifference that the innermost part is not inert. Now we have to note\nthat in those aggregates of cells constituting the _Metaphyta_ and\n_Metazoa_, analogous distributions also exist. In plants they are of\ncourse not to be looked for in leaves and other deciduous portions, but\nonly in portions of long duration--stems and branches. Naturally, too,\nwe need not expect them in plants having modes of growth which early\nproduce an outer practically dead part, that effectually shields the\ninner actively living part of the stem from the influence of the\nmedium--long-lived acrogens such as tree-ferns and long-lived endogens\nsuch as palms. But in the highest plants, exogens, which have the\nactively living part of their stems within reach of environing agencies,\nwe find this part,--the cambium layer,--is one from which there is a\ngrowth inwards forming wood, and a growth outwards forming bark: there\nis an increasingly thick covering (where it does not scale off) of\ntissue changed by the medium, and inside this a film of highest\nvitality. In so far as concerns the present argument, it is the same\nwith the _Metazoa_, or at least all of them which have developed\norganizations. The outer skin grows up from a limiting plane, or layer,\na little distance below the surface--a place of predominant vital\nactivity. Here perpetually arise new cells, which, as they develop, are\nthrust outwards and form the epidermis: flattening and drying up as they\napproach the surface, whence, having for a time served to shield the\nparts below, they finally scale off and leave younger ones to take their\nplaces. This still undifferentiated tissue forming the base of the\nepidermis, and existing also as a source of renewal in internal organs,\nis the essentially living substance; and facts above given imply that it\nwas the action of the medium on this essentially living substance,\nwhich, during early stages in the organization of the _Metazoa_,\ninitiated that protective envelope which presently became an inherited\nstructure--a structure which, though now mainly inherited, still\ncontinues to be modifiable by its initiator.\n\nFully to perceive the way in which these evidences compel us to\nrecognize the influence of the medium as a primordial factor, we need\nbut conceive them as interpreted without it. Suppose, for instance, we\nsay that the structure of the epidermis is wholly determined by the\nnatural selection of favourable variations; what must be the position\ntaken in presence of the fact above named, that when mucous membrane is\nexposed to the air its cell-structure changes into the cell-structure of\nskin? The position taken must be this:--Though mucous membrane in a\nhighly-evolved individual organism, thus shows the powerful effect of\nthe medium on its surface; yet we must not suppose that the medium had\nthe effect of producing such a cell-structure on the surfaces of\nprimitive forms, undifferentiated though they were; or, if we suppose\nthat such an effect was produced on them, we must not suppose that it\nwas inheritable. Contrariwise, we must suppose that such effect of the\nmedium either was not wrought at all, or that it was evanescent: though\nrepeated through millions upon millions of generations it left no\ntraces. And we must conclude that this skin-structure arose only in\nconsequence of spontaneous variations not physically initiated (though\nlike those physically initiated) which natural selection laid hold of\nand increased. Does any one think this a tenable position?\n\n       *       *       *       *       *\n\nAnd now we approach the last and chief series of morphological phenomena\nwhich must be ascribed to the direct action of environing matters and\nforces. These are presented to us when we study the early stages in the\ndevelopment of the embryos of the _Metazoa_ in general.\n\nWe will set out with the fact already noted in passing, that after\nrepeated spontaneous fissions have changed the original fertilized\ngerm-cell into that cluster of cells which forms a gemmule or a\nprimitive ovum, the first contrast which arises is between the\nperipheral parts and the central parts. Where, as with lower creatures\nwhich do not lay up large stores of nutriment with the germs of their\noffspring, the inner mass is inconsiderable, the outer layer of cells,\nwhich are presently made quite small by repeated subdivisions, forms a\nmembrane extending over the whole surface--the blastoderm. The next\nstage of development, which ends in this covering layer becoming double,\nis reached in two ways--by invagination and by delamination; but which\nis the original way and which the abridged way, is not quite certain. Of\ninvagination, multitudinously exemplified in the lowest types, Mr.\nBalfour says:--\"On purely _a priori_ grounds there is in my opinion more\nto be said for invagination than for any other view\";[57] and, for\npresent purposes, it will suffice if we limit ourselves to this: making\nits nature clear to the general reader by a simple illustration.\n\nTake a small india-rubber ball--not of the inflated kind, nor of the\nsolid kind, but of the kind about an inch or so in diameter with a small\nhole through which, under pressure, the air escapes. Suppose that\ninstead of consisting of india-rubber its wall consists of small cells\nmade polyhedral in form by mutual pressure, and united together. This\nwill represent the blastoderm. Now with the finger, thrust in one side\nof the ball until it touches the other: so making a cup. This action\nwill stand for the process of invagination. Imagine that by continuance\nof it, the hemispherical cup becomes very much deepened and the opening\nnarrowed, until the cup becomes a sac, of which the introverted wall is\neverywhere in contact with the outer wall. This will represent the\ntwo-layered \"gastrula\"--the simplest ancestral form of the _Metazoa_: a\nform which is permanently represented in some of the lowest types; for\nit needs but tentacles round the mouth of the sac, to produce a common\nhydra. Here the fact which it chiefly concerns us to remark, is that of\nthese two layers the outer, called in embryological language the\nepiblast, continues to carry on direct converse with the forces and\nmatters in the environment; while the inner, called the hypoblast, comes\nin contact with such only of these matters as are put into the\nfood-cavity which it lines. We have further to note that in the embryos\nof _Metazoa_ at all advanced in organization, there arises between these\ntwo layers a third--the mesoblast. The origin of this is seen in types\nwhere the developmental process is not obscured by the presence of a\nlarge food-yolk. While the above-described introversion is taking place,\nand before the inner surfaces of the resulting epiblast and hypoblast\nhave come into contact, cells, or amoeboid units equivalent to them,\nare budded off from one or both of these inner surfaces, or some part of\none or other; and these form a layer which eventually lies between the\nother two--a layer which, as this mode of formation implies, never has\nany converse with the surrounding medium and its contents, or with the\nnutritive bodies taken in from it. The striking facts to which this\ndescription is a necessary introduction, may now be stated. From the\nouter layer, or epiblast, are developed the permanent epidermis and its\nout-growths, the nervous system, and the organs of sense. From the\nintroverted layer, or hypoblast, are developed the alimentary canal and\nthose parts of its appended organs, liver, pancreas, &c., which are\nconcerned in delivering their secretions into the alimentary canal, as\nwell as the linings of those ramifying tubes in the lungs which convey\nair to the places where gaseous exchange is effected. And from the\nmesoblast originate the bones, the muscles, the heart and blood-vessels,\nand the lymphatics, together with such parts of various internal organs\nas are most remotely concerned with the outer world. Minor\nqualifications being admitted, there remain the broad general facts,\nthat out of that part of the external layer which remains permanently\nexternal, are developed all the structures which carry on intercourse\nwith the medium and its contents, active and passive; out of the\nintroverted part of this external layer, are developed the structures\nwhich carry on intercourse with the quasi-external substances that are\ntaken into the interior--solid food, water, and air; while out of the\nmesoblast are developed structures which have never had, from first to\nlast, any intercourse with the environment. Let us contemplate these\ngeneral facts.\n\nWho would have imagined that the nervous system is a modified portion of\nthe primitive epidermis? In the absence of proofs furnished by the\nconcurrent testimony of embryologists during the last thirty or forty\nyears, who would have believed that the brain arises from an infolded\ntract of the outer skin, which, sinking down beneath the surface,\nbecomes imbedded in other tissues and eventually surrounded by a bony\ncase? Yet the human nervous system in common with the nervous systems of\nlower animals is thus originated. In the words of Mr. Balfour, early\nembryological changes imply that--\n\n     \"the functions of the central nervous system, which were originally\n     taken by the whole skin, became gradually concentrated in a special\n     part of the skin which was step by step removed from the surface,\n     and has finally become in the higher types a well-defined organ\n     imbedded in the subdermal tissues.... The embryological evidence\n     shows that the ganglion-cells of the central part of the nervous\n     system are originally derived from the simple undifferentiated\n     epithelial cells of the surface of the body.\"[58]\n\nLess startling perhaps, though still startling enough, is the fact that\nthe eye is evolved out of a portion of the skin; and that while the\ncrystalline lens and its surroundings thus originate, the \"percipient\nportions of the organs of special sense, especially of optic organs, are\noften formed from the same part of the primitive epidermis\" which forms\nthe central nervous system.[59] Similarly is it with the organs for\nsmelling and hearing. These, too, begin as sacs formed by infoldings of\nthe epidermis; and while their parts are developing they are joined from\nwithin by nervous structures which were themselves epidermic in origin.\nHow are we to interpret these strange transformations? Observing, as we\npass, how absurd from the point of view of the special-creationist,\nwould appear such a filiation of structures, and such a round-about\nmode of embryonic development, we have here to remark that the process\nis not one to have been anticipated as a result of natural selection.\nAfter numbers of spontaneous variations had occurred, as the hypothesis\nimplies, in useless ways, the variation which primarily initiated a\nnervous centre might reasonably have been expected to occur in some\ninternal part where it would be fitly located. Its initiation in a\ndangerous place and subsequent migration to a safe place, would be\nincomprehensible. Not so if we bear in mind the cardinal truth above set\nforth, that the structures for holding converse with the medium and its\ncontents, arise in that completely superficial part which is directly\naffected by the medium and its contents; and if we draw the inference\nthat the external actions themselves initiate the structures. These once\ncommenced, and furthered by natural selection where favourable to life,\nwould form the first term of a series ending in developed sense organs\nand a developed nervous system.[60]\n\nThough it would enforce the argument, I must, for brevity's sake, pass\nover the analogous evolution of that introverted layer, or hypoblast,\nout of which the alimentary canal and attached organs arise. It will\nsuffice to emphasize the fact that having been originally external, this\nlayer continues in its developed form to have a quasi-externality, alike\nin its digesting part and in its respiratory part; since it continues to\ndeal with matters alien to the organism. I must also refrain from\ndwelling at length on the fact already adverted to, that the\nintermediate derived layer, or mesoblast, which was at the outset\ncompletely internal, originates those structures which ever remain\ncompletely internal, and have no communication with the environment save\nthrough the structures developed from the other two: an antithesis which\nhas great significance.\n\nHere, instead of dwelling on these details, it will be better to draw\nattention to the most general aspect of the facts. Whatever may be the\ncourse of subsequent changes, the first change is the formation of a\nsuperficial layer or blastoderm; and by whatever series of\ntransformations the adult structure is reached, it is from the\nblastoderm that all the organs forming the adult originate. Why this\nmarvellous fact?\n\nMeaning is given to it if we go back to the first stage in which\n_Protozoa_, having by repeated fissions formed a cluster, then arranged\nthemselves into a hollow sphere, as do the protophytes forming a\n_Volvox_. Originally alike all over its surface, the hollow sphere of\nciliated units thus formed, would, if not quite spherical, assume a\nconstant attitude when moving through the water; and hence one part of\nthe spheroid would more frequently than the rest come in contact with\nnutritive matters to be taken in. A division of labour resulting from\nsuch a variation being advantageous, and tending therefore to increase\nin descendants, would end in a differentiation like that shown in the\ngemmules of various low types of _Metazoa_, which, ovate in shape, are\nciliated over one part of the surface only. There would arise a form in\nwhich the cilium-bearing units effected locomotion and aeration; while\non the others, assuming an amoeba-like character, devolved the\nfunction of absorbing food: a primordial specialization variously\nindicated by evidence.[61] Just noting that an ancestral origin of this\nkind is implied by the fact that in low types of _Metazoa_ a hollow\nsphere of cells is the form first assumed by the unfolding embryo, I\ndraw attention to the point here of chief interest; namely that the\nprimary differentiation of this hollow sphere is in such case determined\nby a difference in the converse of its parts with the medium and its\ncontents; and that the subsequent invagination arises by a continuance\nof this differential converse.\n\nEven neglecting this first stage and commencing with the next, in which\na \"gastrula\" has been produced by the permanent introversion of one\nportion of the surface of the hollow sphere, it will suffice if we\nconsider what must thereafter have happened. That which continued to be\nthe outer surface was the part which from time to time touched quiescent\nmasses and occasionally received the collisions consequent on its own\nmotions or the motions of other things. It was the part to receive the\nsound-vibrations occasionally propagated through the water; the part to\nbe affected more strongly than any other by those variations in the\namounts of light caused by the passing of small bodies close to it; and\nthe part which met those diffused molecules constituting odours. That is\nto say, from the beginning the surface was the part on which there fell\nthe various influences pervading the environment, the part by which\nthere was received those impressions from the environment serving for\nthe guidance of actions, and the part which had to bear the mechanical\nre-actions consequent upon such actions. Necessarily, therefore, the\nsurface was the part in which were initiated the various\ninstrumentalities for carrying on intercourse with the environment. To\nsuppose otherwise is to suppose that such instrumentalities arose\ninternally where they could neither be operated on by surrounding\nagencies nor operate on them,--where the differentiating forces did not\ncome into play, and the differentiated structures had nothing to do; and\nit is to suppose that meanwhile the parts directly exposed to the\ndifferentiating forces remained unchanged. Clearly, then, organization\ncould not but begin on the surface; and having thus begun, its\nsubsequent course could not but be determined by its superficial origin.\nAnd hence these remarkable facts showing us that individual evolution is\naccomplished by successive in-foldings and in-growings. Doubtless\nnatural selection soon came into action, as, for example, in the removal\nof the rudimentary nervous centres from the surface; since an\nindividual in which they were a little more deeply seated would be less\nlikely to be incapacitated by injury of them. And so in multitudinous\nother ways. But nevertheless, as we here see, natural selection could\noperate only under subjection. It could do no more than take advantage\nof those structural changes which the medium and its contents initiated.\n\nSee, then, how large has been the part played by this primordial factor.\nHad it done no more than give to _Protozoa_ and _Protophyta_ that\ncell-form which characterizes them--had it done no more than entail the\ncellular composition which is so remarkable a trait of _Metazoa_ and\n_Metaphyta_--had it done no more than cause the repetition in all\nvisible animals and plants of that primary differentiation of outer from\ninner which it first wrought in animals and plants invisible to the\nnaked eye; it would have done much towards giving to organisms of all\nkinds certain leading traits. But it has done more than this. By causing\nthe first differentiations of those clusters of units out of which\nvisible animals in general arose, it fixed the starting place for\norganization, and therefore determined the course of organization; and,\ndoing this, gave indelible traits to embryonic transformations and to\nadult structures.\n\n       *       *       *       *       *\n\nThough mainly carried on after the inductive method, the argument at the\nclose of the foregoing section has passed into the deductive. Here let\nus follow for a space the deductive method pure and simple. Doubtless in\nbiology _a priori_ reasoning is dangerous; but there can be no danger in\nconsidering whether its results coincide with those reached by reasoning\n_a posteriori_.\n\nBiologists in general agree that in the present state of the world, no\nsuch thing happens as the rise of a living creature out of non-living\nmatter. They do not deny, however, that at a remote period in the past,\nwhen the temperature of the Earth's surface was much higher than at\npresent, and other physical conditions were unlike those we know,\ninorganic matter, through successive complications, gave origin to\norganic matter. So many substances once supposed to belong exclusively\nto living bodies, have now been formed artificially, that men of science\nscarcely question the conclusion that there are conditions under which,\nby yet another step of composition, quaternary compounds of lower types\npass into those of highest types. That there once took place gradual\ndivergence of the organic from the inorganic, is, indeed, a necessary\nimplication of the hypothesis of Evolution, taken as a whole; and if we\naccept it as a whole, we must put to ourselves the question--What were\nthe early stages of progress which followed, after the most complex form\nof matter had arisen out of forms of matter a degree less complex?\n\nAt first, protoplasm could have had no proclivities to one or other\narrangement of parts; unless, indeed, a purely mechanical proclivity\ntowards a spherical form when suspended in a liquid. At the outset it\nmust have been passive. In respect of its passivity, primitive organic\nmatter must have been like inorganic matter. No such thing as\nspontaneous variation could have occurred in it; for variation implies\nsome habitual course of change from which it is a divergence, and is\ntherefore excluded where there is no habitual course of change. In the\nabsence of that cyclical series of metamorphoses which even the simplest\nliving thing now shows us, as a result of its inherited constitution,\nthere could be no _point d'appui_ for natural selection. How, then, did\norganic evolution begin?\n\nIf a primitive mass of organic matter was like a mass of inorganic\nmatter in respect of its passivity, and differed only in respect of its\ngreater changeableness; then we must infer that its first changes\nconformed to the same general law as do the changes of an inorganic\nmass. The instability of the homogeneous is a universal principle. In\nall cases the homogeneous tends to pass into the heterogeneous, and the\nless heterogeneous into the more heterogeneous. In the primordial units\nof protoplasm, then, the step with which evolution commenced must have\nbeen the passage from a state of complete likeness throughout the mass\nto a state in which there existed some unlikeness. Further, the cause of\nthis step in one of these portions of organic matter, as in any portion\nof inorganic matter, must have been the different exposure of its parts\nto incident forces. What incident forces? Those of its medium or\nenvironment. Which were the parts thus differently exposed? Necessarily\nthe outside and the inside. Inevitably, then, alike in the organic\naggregate and the inorganic aggregate (supposing it to have coherence\nenough to maintain constant relative positions among its parts), the\nfirst fall from homogeneity to heterogeneity must always have been the\ndifferentiation of the external surface from the internal contents. No\nmatter whether the modification was physical or chemical, one of\ncomposition or of decomposition, it comes within the same\ngeneralization. The direct action of the medium was the primordial\nfactor of organic evolution.\n\n       *       *       *       *       *\n\nAnd now, finally, let us look at the factors in their _ensemble_, and\nconsider the respective parts they play: observing, especially, the ways\nin which, at successive stages, they severally give place one to another\nin degree of importance.\n\nActing alone, the primordial factor must have initiated the primary\ndifferentiation in all units of protoplasm alike. I say alike, but I\nmust forthwith qualify the word. For since surrounding influences,\nphysical and chemical, could not be absolutely the same in all places,\nespecially when the first rudiments of living things had spread over a\nconsiderable area, there necessarily arose small contrasts between the\ndegrees and kinds of superficial differentiation effected. As soon as\nthese became decided, natural selection came into play; for inevitably\nthe unlikenesses produced among the units had effects on their lives:\nthere was survival of some among the modified forms rather than others.\nUtterly in the dark though we are respecting the causes which set up\nthat process of fission everywhere occurring among the minutest forms of\nlife, we must infer that, when established, it furthered the spread of\nthose which were most favourably differentiated by the medium. Though\nnatural selection must have become increasingly active when once it had\ngot a start; yet the differentiating action of the medium never ceased\nto be a co-operator in the development of these first animals and\nplants. Again taking the lead as there arose the composite forms of\nanimals and plants, and again losing the lead with that advancing\ndifferentiation of these higher types which gave more scope to natural\nselection, it nevertheless continued, and must ever continue, to be a\ncause, both direct and indirect, of modifications in structure.\n\nAlong with that remarkable process which, beginning in minute forms with\nwhat is called conjugation, developed into sexual generation, there came\ninto play causes of frequent and marked fortuitous variations. The\nmixtures of constitutional proclivities made more or less unlike by\nunlikenesses of physical conditions, inevitably led to occasional\nconcurrences of forces producing deviations of structure. These were of\ncourse mostly suppressed, but sometimes increased, by survival of the\nfittest. When, along with the growing multiplication in forms of life,\nconflict and competition became continually more active, fortuitous\nvariations of structure of no account in the converse with the medium,\nbecame of much account in the struggle with enemies and competitors; and\nnatural selection of such variations became the predominant factor.\nEspecially throughout the plant-world its action appears to have been\nimmensely the most important; and throughout that large part of the\nanimal world characterized by relative inactivity, the survival of\nindividuals that had varied in favourable ways, must all along have been\nthe chief cause of the divergence of species and the occasional\nproduction of higher ones.\n\nBut gradually with that increase of activity which we see on ascending\nto successively higher grades of animals, and especially with that\nincreased complexity of life which we also see, there came more and more\ninto play as a factor, the inheritance of those modifications of\nstructure caused by modifications of function. Eventually, among\ncreatures of high organization, this factor became an important one; and\nI think there is reason to conclude that, in the case of the highest of\ncreatures, civilized men, among whom the kinds of variation which affect\nsurvival are too multitudinous to permit easy selection of any one, and\namong whom survival of the fittest is greatly interfered with, it has\nbecome the chief factor: such aid as survival of the fittest gives,\nbeing usually limited to the preservation of those in whom the totality\nof the faculties has been most favourably moulded by functional changes.\n\nOf course this sketch of the relations among the factors must be taken\nas in large measure a speculation. We are now too far removed from the\nbeginnings of life to obtain data for anything more than tentative\nconclusions respecting its earliest stages; especially in the absence of\nany clue to the mode in which multiplication, first agamogenetic and\nthen gamogenetic, was initiated. But it has seemed to me not amiss to\npresent this general conception, by way of showing how the deductive\ninterpretation harmonizes with the several inferences reached by\ninduction.\n\n       *       *       *       *       *\n\nIn his article on Evolution in the _Encyclopaedia Britannica_, Professor\nHuxley writes as follows:--\n\n     \"How far 'natural selection' suffices for the production of\n     species remains to be seen. Few can doubt that, if not the whole\n     cause, it is a very important factor in that operation.... On the\n     evidence of palaeontology, the evolution of many existing forms of\n     animal life from their predecessors is no longer an hypothesis, but\n     an historical fact; it is only the nature of the physiological\n     factors to which that evolution is due which is still open to\n     discussion.\"\n\nWith these passages I may fitly join a remark made in the admirable\naddress Prof. Huxley delivered before unveiling the statue of Mr. Darwin\nin the Museum at South Kensington. Deprecating the supposition that an\nauthoritative sanction was given by the ceremony to the current ideas\nconcerning organic evolution, he said that \"science commits suicide when\nit adopts a creed.\"\n\nAlong with larger motives, one motive which has joined in prompting the\nforegoing articles, has been the desire to point out that already among\nbiologists, the beliefs concerning the origin of species have assumed\ntoo much the character of a creed; and that while becoming settled they\nhave been narrowed. So far from further broadening that broader view\nwhich Mr. Darwin reached as he grew older, his followers appear to have\nretrograded towards a more restricted view than he ever expressed. Thus\nthere seems occasion for recognizing the warning uttered by Prof.\nHuxley, as not uncalled for.\n\nWhatever may be thought of the arguments and conclusions set forth in\nthis article and the preceding one, they will perhaps serve to show that\nit is as yet far too soon to close the inquiry concerning the causes of\norganic evolution.\n\n\nNOTE.\n\n    [_The following passages formed part of a preface to the small\n    volume in which the foregoing essay re-appeared. I append them here\n    as they cannot now be conveniently prefixed._]\n\nThough the direct bearings of the arguments contained in this Essay are\nbiological, the argument contained in its first half has indirect\nbearings upon Psychology, Ethics, and Sociology. My belief in the\nprofound importance of these indirect bearings, was originally a chief\nprompter to set forth the argument; and it now prompts me to re-issue it\nin permanent form.\n\nThough mental phenomena of many kinds, and especially of the simpler\nkinds, are explicable only as resulting from the natural selection of\nfavourable variations; yet there are, I believe, still more numerous\nmental phenomena, including all those of any considerable complexity,\nwhich cannot be explained otherwise than as results of the inheritance\nof functionally-produced modifications. What theory of psychological\nevolution is espoused, thus depends on acceptance or rejection of the\ndoctrine that not only in the individual, but in the successions of\nindividuals, use and disuse of parts produce respectively increase and\ndecrease of them.\n\nOf course there are involved the conceptions we form of the genesis and\nnature of our higher emotions; and, by implication, the conceptions we\nform of our moral intuitions. If functionally-produced modifications are\ninheritable, then the mental associations habitually produced in\nindividuals by experiences of the relations between actions and their\nconsequences, pleasurable or painful, may, in the successions of\nindividuals, generate innate tendencies to like or dislike such actions.\nBut if not, the genesis of such tendencies is, as we shall see, not\nsatisfactorily explicable.\n\nThat our sociological beliefs must also be profoundly affected by the\nconclusions we draw on this point, is obvious. If a nation is modified\n_en masse_ by transmission of the effects produced on the natures of its\nmembers by those modes of daily activity which its institutions and\ncircumstances involve; then we must infer that such institutions and\ncircumstances mould its members far more rapidly and comprehensively\nthan they can do if the solo cause of adaptation to them is the more\nfrequent survival of individuals who happen to have varied in\nfavourable ways.\n\nI will add only that, considering the width and depth of the effects\nwhich acceptance of one or other of these hypotheses must have on our\nviews of Life, Mind, Morals, and Politics, the question--Which of them\nis true? demands, beyond all other questions whatever, the attention of\nscientific men.\n\n       *       *       *       *       *\n\nAfter the above articles were published, I received from Dr. Downes a\ncopy of a paper \"On the Influence of Light on Protoplasm,\" written by\nhimself and Mr. T.P. Blunt, M.A., which was communicated to the Royal\nSociety in 1878. It was a continuation of a preceding paper which,\nreferring chiefly to _Bacteria_, contended that--\n\n     \"Light is inimical to, and under favourable conditions may wholly\n     prevent, the development of these organisms.\"\n\nThis supplementary paper goes on to show that the injurious effect of\nlight upon protoplasm results only in presence of oxygen. Taking first a\ncomparatively simple type of molecule which enters into the composition\nof organic matter, the authors say, after detailing experiments:--\n\n     \"It was evident, therefore, that _oxygen_ was the agent of\n     destruction under the influence of sunlight.\"\n\nAnd accounts of experiments upon minute organisms are followed by the\nsentence--\n\n     \"It seemed, therefore, that in absence of an atmosphere, light\n     failed entirely to produce any effect on such organisms as were\n     able to appear.\"\n\nThey sum up the results of their experiments in the paragraph--\n\n     \"We conclude, therefore, both from analogy and from direct\n     experiment, that the observed action on these organisms is not\n     dependent on light _per se_, but that the presence of free oxygen\n     is necessary; light and oxygen together accomplishing what neither\n     can do alone: and the inference seems irresistible that the effect\n     produced is a gradual oxidation of the constituent protoplasm of\n     these organisms, and that, in this respect, protoplasm, although\n     living, is not exempt from laws which appear to govern the\n     relations of light and oxygen to forms of matter less highly\n     endowed. A force which is indirectly absolutely essential to life\n     as we know it, and matter in the absence of which life has not yet\n     been proved to exist, here unite for its destruction.\"\n\nWhat is the obvious implication? If oxygen in presence of light destroys\none of these minutest portions of protoplasm, what will be its effect on\na larger portion of protoplasm? It will work an effect on the surface\ninstead of on the whole mass. Not like the minutest mass made inert all\nthrough, the larger mass will be made inert only on its outside; and,\nindeed, the like will happen with the minutest mass if the light or the\noxygen is very small in quantity. Hence there will result an envelope of\nchanged matter, inclosing and protecting the unchanged protoplasm--there\nwill result a rudimentary cell-wall.\n\nFOOTNOTES:\n\n[Footnote 41: It is probable that this shortening has resulted not\ndirectly but indirectly, from the selection of individuals which were\nnoted for tenacity of hold; for the bull-dog's peculiarity in this\nrespect seems due to relative shortness of the upper jaw, giving the\nunderhung structure which, involving retreat of the nostrils, enables\nthe dog to continue breathing while holding.]\n\n[Footnote 42: Though Mr. Darwin approved of this expression and\noccasionally employed it, he did not adopt it for general use;\ncontending, very truly, that the expression Natural Selection is in some\ncases more convenient. See _Animals and Plants under Domestication_\n(first edition) Vol. i, p. 6; and _Origin of Species_ (sixth edition) p.\n49.]\n\n[Footnote 43: It is true that while not deliberately admitted by Mr.\nDarwin, these effects are not denied by him. In his _Animals and Plants\nunder Domestication_ (vol. ii, 281), he refers to certain chapters in\nthe _Principles of Biology_, in which I have discussed this general\ninter-action of the medium and the organism, and ascribed certain most\ngeneral traits to it. But though, by his expressions, he implies a\nsympathetic attention to the argument, he does not in such way adopt the\nconclusion as to assign to this factor any share in the genesis of\norganic structures--much less that large share which I believe it has\nhad. I did not myself at that time, nor indeed until quite recently, see\nhow extensive and profound have been the influences on organization\nwhich, as we shall presently see, are traceable to the early results of\nthis fundamental relation between organism and medium. I may add that it\nis in an essay on \"Transcendental Physiology,\" first published in 1857,\nthat the line of thought here followed out in its wider bearings, was\nfirst entered upon.]\n\n[Footnote 44: _Text-Book of Botany, &c._ by Julius Sachs. Translated by\nA. W. Bennett and W. T. T. Dyer.]\n\n[Footnote 45: _A Manual of the Infusoria_, by W. Saville Kent. Vol. i,\np. 232.]\n\n[Footnote 46: _Ib._ Vol. i, p. 241.]\n\n[Footnote 47: Kent, Vol. i, p. 56.]\n\n[Footnote 48: _Ib._ Vol. i, p. 57.]\n\n[Footnote 49: _The Elements of Comparative Anatomy_, by T. H. Huxley,\npp. 7-9.]\n\n[Footnote 50: _A Treatise on Comparative Embryology_, by F. M. Balfour,\nVol. ii, chap. xiii.]\n\n[Footnote 51: Sachs, p. 210.]\n\n[Footnote 52: _Ibid._ pp. 83-4.]\n\n[Footnote 53: _Ibid._ p. 185.]\n\n[Footnote 54: _Ibid._ 80.]\n\n[Footnote 55: Sachs, p. 83.]\n\n[Footnote 56: _Ibid._ p. 147.]\n\n[Footnote 57: _A Treatise on Comparative Embryology._ By Francis M.\nBalfour, LL.D., F.R.S. Vol. ii, p. 343 (second edition).]\n\n[Footnote 58: Balfour, l.c. Vol. ii, 400-1.]\n\n[Footnote 59: Balfour, l.c. Vol. ii, p. 401.]\n\n[Footnote 60: For a general delineation of the changes by which the\ndevelopment is effected, see Balfour, l.c. Vol. ii, pp. 401-4.]\n\n[Footnote 61: _See_ Balfour, Vol. i, 149 and Vol. ii, 343-4.]\n\n\n\n\nA COUNTER-CRITICISM.\n\n    [_First published in_ The Nineteenth Century_, for February,_ 1888.]\n\n\nWhile I do not concur in sundry of the statements and conclusions\ncontained in the article entitled \"A Great Confession,\" contributed by\nthe Duke of Argyll to the last number of this Review, yet I am obliged\nto him for having raised afresh the question discussed in it. Though the\ninjunction \"Rest and be thankful,\" is one for which in many spheres much\nmay be said--especially in the political, where undue restlessness is\nproving very mischievous; yet rest and be thankful is an injunction out\nof place in science. Unhappily, while politicians have not duly regarded\nit, it appears to have been taken to heart too much by naturalists; in\nso far, at least, as concerns the question of the origin of species.\n\nThe new biological orthodoxy behaves just as the old biological\northodoxy did. In the days before Darwin, those who occupied themselves\nwith the phenomena of life, passed by with unobservant eyes the\nmultitudinous facts which point to an evolutionary origin for plants and\nanimals; and they turned deaf ears to those who insisted on the\nsignificance of these facts. Now that they have come to believe in this\nevolutionary origin, and have at the same time accepted the hypothesis\nthat natural selection has been the sole cause of the evolution, they\nare similarly unobservant of the multitudinous facts which cannot\nrationally be ascribed to that cause; and turn deaf ears to those who\nwould draw their attention to them. The attitude is the same; it is only\nthe creed which has changed.\n\nBut, as above implied, though the protest of the Duke of Argyll against\nthis attitude is quite justifiable, it seems to me that many of his\nstatements cannot be sustained. Some of these concern me personally, and\nothers are of impersonal concern. I propose to deal with them in the\norder in which they occur.\n\n       *       *       *       *       *\n\nOn page 144 the Duke of Argyll quotes me as omitting \"for the present\nany consideration of a factor which may be distinguished as primordial;\"\nand he represents me as implying by this \"that Darwin's ultimate\nconception of some primordial 'breathing of the breath of life' is a\nconception which can be omitted only 'for the present.'\" Even had there\nbeen no other obvious interpretation, it would have been a somewhat rash\nassumption that this was my meaning when referring to an omitted factor;\nand it is surprising that this assumption should have been made after\nreading the second of the two articles criticised, in which this factor\nomitted from the first is dealt with: this omitted third factor being\nthe direct physico-chemical action of the medium on the organism. Such a\nthought as that which the Duke of Argyll ascribes to me, is so\nincongruous with the beliefs I have in many places expressed that the\nascription of it never occurred to me as possible.\n\nLower down on the same page are some other sentences having personal\nimplications, which I must dispose of before going into the general\nquestion. The Duke says \"it is more than doubtful whether any value\nattaches to the new factor with which he [I] desires to supplement it\n[natural selection]\"; and he thinks it \"unaccountable\" that I \"should\nmake so great a fuss about so small a matter as the effect of use and\ndisuse of particular organs as a separate and a newly-recognised\nfactor in the development of varieties.\" I do not suppose that the Duke\nof Argyll intended to cast upon me the disagreeable imputation, that I\nclaim as new that which all who are even slightly acquainted with the\nfacts know to be anything rather than new. But his words certainly do\nthis. How he should have thus written in spite of the extensive\nknowledge of the matter which he evidently has, and how he should have\nthus written in presence of the evidence contained in the articles he\ncriticizes, I cannot understand. Naturalists, and multitudes besides\nnaturalists, know that the hypothesis which I am represented as putting\nforward as new, is much older than the hypothesis of natural\nselection--goes back at least as far as Dr. Erasmus Darwin. My purpose\nwas to bring into the foreground again a factor which has, I think, been\nof late years improperly ignored; to show that Mr. Darwin recognized\nthis factor in an increasing degree as he grew older (by showing which I\nshould have thought I sufficiently excluded the supposition that I\nbrought it forward as new); to give further evidence that this factor is\nin operation; to show there are numerous phenomena which cannot be\ninterpreted without it; and to argue that if proved operative in any\ncase, it may be inferred that it is operative on all structures having\nactive functions.\n\nStrangely enough, this passage, in which I am represented as implying\nnovelty in a doctrine which I have merely sought to emphasize and\nextend, is immediately succeeded by a passage in which the Duke of\nArgyll himself represents the doctrine as being familiar and well\nestablished:--\n\n     \"That organs thus enfeebled [i.e. by persistent disuse] are\n     transmitted by inheritance to offspring in a like condition of\n     functional and structural decline, is a correlated physiological\n     doctrine not generally disputed. The converse case--of increased\n     strength and development arising out of the habitual and healthy\n     use of special organs, and of the transmission of these to\n     offspring--is a case illustrated by many examples in the breeding\n     of domestic animals. I do not know to what else we can attribute\n     the long slender legs and bodies of greyhounds so manifestly\n     adapted to speed of foot, or the delicate powers of smell in\n     pointers and setters, or a dozen cases of modified structure\n     effected by artificial selection.\"\n\nIn none of the assertions contained in this passage can I agree. Had the\ninheritance of \"functional and structural decline\" been \"not generally\ndisputed,\" half my argument would have been needless; and had the\ninheritance of \"increased strength and development\" caused by use been\nrecognized, as \"illustrated by many examples,\" the other half of my\nargument would have been needless. But both are disputed; and, if not\npositively denied, are held to be unproved. Greyhounds and pointers do\nnot yield valid evidence, because their peculiarities are more due to\nartificial selection than to any other cause. It may, indeed, be doubted\nwhether greyhounds use their legs more than other dogs. Dogs of all\nkinds are daily in the habit of running about and chasing one another at\nthe top of their speed--other dogs more frequently than greyhounds,\nwhich are not much given to play. The occasions on which greyhounds\nexercise their legs in chasing hares, occupy but inconsiderable spaces\nin their lives, and can play but small parts in developing their legs.\nAnd then, how about their long heads and sharp noses? Are these\ndeveloped by running? The structure of the greyhound is explicable as a\nresult mainly of selection of variations occasionally arising from\nunknown causes; but it is inexplicable otherwise. Still more obviously\ninvalid is the evidence said to be furnished by pointers and setters.\nHow can these be said to exercise their organs of smell more than other\ndogs? Do not all dogs occupy themselves in sniffing about here and there\nall day long: tracing animals of their own kind and of other kinds?\nInstead of admitting that the olfactory sense is more exercised in\npointers and setters than in other dogs, it might, contrariwise, be\ncontended that it is exercised less; seeing that during the greater\nparts of their lives they are shut up in kennels where the varieties of\nodours, on which to practise their noses, is but small. Clearly if\nbreeders of sporting dogs have from early days habitually bred from\nthose puppies of each litter which had the keenest noses (and it is\nundeniable that the puppies of each litter are made different from one\nanother, as are the children in each human family, by unknown\ncombinations of causes), then the existence of such remarkable powers in\npointers and setters may be accounted for; while it is otherwise\nunaccountable. These instances, and many others such, I should have\ngladly used in support of my argument, had they been available; but\nunfortunately they are not.\n\nOn the next page of the Duke of Argyll's article (page 145), occurs a\npassage which I must quote at length before I can deal effectually with\nits various statements. It runs as follows:--\n\n     \"But if natural selection is a mere phrase, vague enough and wide\n     enough to cover any number of the physical causes concerned in\n     ordinary generation, then the whole of Mr. Spencer's laborious\n     argument in favour of his 'other factor' becomes an argument worse\n     than superfluous. It is wholly fallacious in assuming that this\n     'factor' and 'natural selection' are at all exclusive of, or even\n     separate from, each other. The factor thus assumed to be new is\n     simply one of the subordinate cases of heredity. But heredity is\n     the central idea of natural selection. Therefore natural selection\n     includes and covers all the causes which can possibly operate\n     through inheritance. There is thus no difficulty whatever in\n     referring it to the same one factor whose solitary dominion Mr.\n     Spencer has plucked up courage to dispute. He will never succeed in\n     shaking its dictatorship by such a small rebellion. His little\n     contention is like some bit of Bumbledom setting up for Home\n     Rule--some parochial vestry claiming independence of a universal\n     empire. It pretends to set up for itself in some fragment of an\n     idea. But here is not even a fragment to boast of or to stand up\n     for. His new factor in organic evolution has neither independence\n     nor novelty. Mr. Spencer is able to quote himself as having\n     mentioned it in his _Principles of Biology_ published some twenty\n     years ago; and by a careful ransacking of Darwin he shows that the\n     idea was familiar to and admitted by him at least in his last\n     edition of the _Origin of Species_.... Darwin was a man so much\n     wiser than all his followers,\" &c.\n\nHad there not been the Duke of Argyll's signature to the article, I\ncould scarcely have believed that this passage was written by him.\nRemembering that on reading his article in the preceding number of this\nReview, I was struck by the extent of knowledge, clearness of\ndiscrimination, and power of exposition, displayed in it, I can scarcely\nunderstand how there has come from the same pen a passage in which none\nof these traits are exhibited. Even one wholly unacquainted with the\nsubject may see in the last two sentences of the above extract, how\nstrangely its propositions are strung together. While in the first of\nthem I am represented as bringing forward a \"new factor,\" I am in the\nsecond represented as saying that I mentioned it twenty years ago! In\nthe same breath I am described as claiming it as new and asserting it as\nold! So, again, the uninstructed reader, on comparing the first words of\nthe extract with the last, will be surprised on seeing in a scientific\narticle statements so manifestly wanting in precision. If \"natural\nselection is a mere phrase,\" how can Mr. Darwin, who thought it\nexplained the origin of species, be regarded as wise? Surely it must be\nmore than a mere phrase if it is the key to so many otherwise\ninexplicable facts. These examples of incongruous thoughts I give to\nprepare the way; and will now go on to examine the chief propositions\nwhich the quoted passage contains.\n\nThe Duke of Argyll says that \"heredity is the central idea of natural\nselection.\" Now it would, I think, be concluded that those who possess\nthe central idea of a thing have some consciousness of the thing. Yet\nmen have possessed the idea of heredity for any number of generations\nand have been quite unconscious of natural selection. Clearly the\nstatement is misleading. It might just as truly be said that the\noccurrence of structural variations in organisms is the central idea of\nnatural selection. And it might just as truly be said that the action of\nexternal agencies in killing some individuals and fostering others is\nthe central idea of natural selection. No such assertions are correct.\nThe process has three factors--heredity, variation, and external\naction--any one of which being absent, the process ceases. The\nconception contains three corresponding ideas, and if any one be struck\nout, the conception cannot be framed. No one of them is the central\nidea, but they are co-essential ideas.\n\nFrom the erroneous belief that \"heredity is the central idea of natural\nselection\" the Duke of Argyll draws the conclusion, consequently\nerroneous, that \"natural selection includes and covers all the causes\nwhich can possibly operate through inheritance.\" Had he considered the\ncases which, in the _Principles of Biology_, I have cited to illustrate\nthe inheritance of functionally-produced modifications, he would have\nseen that his inference is far from correct. I have instanced the\ndecrease of the jaw among civilized men as a change of structure which\ncannot have been produced by the inheritance of spontaneous, or\nfortuitous, variations. That changes of structure arising from such\nvariations may be maintained and increased in successive generations, it\nis needful that the individuals in whom they occur shall derive from\nthem advantages in the struggle for existence--advantages, too,\nsufficiently great to aid their survival and multiplication in\nconsiderable degrees. But a decrease of jaw reducing its weight by even\nan ounce (which would be a large variation), cannot, by either smaller\nweight carried or smaller nutrition required, have appreciably\nadvantaged any person in the battle of life. Even supposing such\ndiminution of jaw to be beneficial (and in the resulting decay of teeth\nit entails great evils), the benefit can hardly have been such as to\nincrease the relative multiplication of families in which it occurred\ngeneration after generation. Unless it has done this, however, decreased\nsize of the jaw cannot have been produced by the natural selection of\nfavourable variations. How can it then have been produced? Only by\ndecreased function--by the habitual use of soft food, joined, probably,\nwith disuse of the teeth as tools. And now mark that this cause operates\non all members of a society which falls into civilized habits.\nGeneration after generation this decreased function changes its\ncomponent families simultaneously. Natural selection does not cover the\ncase at all--has nothing to do with it. And the like happens in\nmultitudinous other cases. Every species spreading into a new habitat,\ncoming in contact with new food, exposed to a different temperature, to\na drier or moister air, to a more irregular surface, to a new soil, &c.,\n&c., has its members one and all subject to various changed actions,\nwhich influence its muscular, vascular, respiratory, digestive,\nand other systems of organs. If there is inheritance of\nfunctionally-produced modifications, then all its members will transmit\nthe structural alterations wrought in them, and the species will change\nas a whole without the supplanting of some stocks by others. Doubtless\nin respect of certain changes natural selection will co-operate. If the\nspecies, being a predacious one, is brought, by migration, into the\npresence of prey of greater speed than before; then, while all its\nmembers will have their limbs strengthened by extra action, those in\nwhom this muscular adaptation is greatest will have their multiplication\nfurthered; and inheritance of the functionally-increased structures will\nbe aided, in successive generations, by survival of the fittest. But it\ncannot be so with the multitudinous minor changes entailed by the\nmodified life. The majority of these must be of such relative\nunimportance that one of them cannot give to the individual in which it\nbecomes most marked, advantages which predominate over kindred\nadvantages gained by other individuals from other changes more\nfavourably wrought in them. In respect to these, the inherited effects\nof use and disuse must accumulate independently of natural selection.\n\nTo make clear the relations of these two factors to one another and to\nheredity, let us take a case in which the operations of all three may be\nseverally identified and distinguished.\n\nHere is one of those persons, occasionally met with, who has an\nadditional finger on each hand, and who, we will suppose, is a\nblacksmith. He is neither aided nor much hindered by these additional\nfingers; but, by constant use, he has greatly developed the muscles of\nhis right arm. To avoid a perturbing factor, we will assume that his\nwife, too, exercises her arms in an unusual degree: keeps a mangle, and\nhas all the custom of the neighbourhood. Such being the circumstances,\nlet us ask what are the established facts, and what are the beliefs and\ndisbeliefs of biologists.\n\nThe first fact is that this six-fingered blacksmith will be likely to\ntransmit his peculiarity to some of his children; and some of these,\nagain, to theirs. It is proved that, even in the absence of a like\npeculiarity in the other parent, this strange variation of structure\n(which we must ascribe to some fortuitous combination of causes) is\noften inherited for more than one generation. Now the causes which\nproduce this persistent six-fingeredness are unquestionably causes which\n\"operate through inheritance.\" The Duke of Argyll says that \"natural\nselection includes and covers all the causes which can possibly operate\nthrough inheritance.\" How does it cover the causes which operate here?\nNatural selection never comes into play at all. There is no fostering of\nthis peculiarity, since it does not help in the struggle for existence;\nand there is no reason to suppose it is such a hindrance in the struggle\nthat those who have it disappear in consequence. It simply gets\ncancelled in the course of generations by the adverse influences of\nother stocks.\n\nWhile biologists admit, or rather assert, that the peculiarity in the\nblacksmith's arm which was born with him is transmissible, they deny, or\nrather do not admit, that the other peculiarities of his arm, induced by\ndaily labour--its large muscles and strengthened bones--are\ntransmissible. They say that there is no proof. The Duke of Argyll\nthinks that the inheritance of organs enfeebled by disuse is \"not\ngenerally disputed;\" and he thinks there is clear proof that the\nconverse change--increase of size consequent on use--is also inherited.\nBut biologists dispute both of these alleged kinds of inheritance. If\nproof is wanted, it will be found in the proceedings at the last meeting\nof the British Association, in a paper entitled \"Are Acquired Characters\nHereditary?\" by Professor Ray Lankester, and in the discussion raised by\nthat paper. Had this form of inheritance been, as the Duke of Argyll\nsays, \"not generally disputed,\" I should not have written the first of\nthe two articles he criticizes.\n\nBut supposing it proved, as it may hereafter be, that such a\nfunctionally-produced change of structure as the blacksmith's arm shows\nus, is transmissible, the persistent inheritance is again of a kind with\nwhich natural selection has nothing to do. If the greatly strengthened\narm enabled the blacksmith and his descendants, having like strengthened\narms, to carry on the battle of life in a much more successful way than\nit was carried on by other men, survival of the fittest would ensure the\nmaintenance and increase of this trait in successive generations. But\nthe skill of the carpenter enables him to earn quite as much as his\nstronger neighbour. By the various arts he has been taught, the plumber\ngets as large a weekly wage. The small shopkeeper by his foresight in\nbuying and prudence in selling, the village-schoolmaster by his\nknowledge, the farm-bailiff by his diligence and care, succeed in the\nstruggle for existence equally well. The advantage of a strong arm does\nnot predominate over the advantages which other men gain by their innate\nor acquired powers of other kinds; and therefore natural selection\ncannot operate so as to increase the trait. Before it can be increased,\nit is neutralized by the unions of those who have it with those who have\nother traits. To whatever extent, therefore, inheritance of this\nfunctionally-produced modification operates, it operates independently\nof natural selection.\n\nOne other point has to be noted--the relative importance of this factor.\nIf additional developments of muscles and bones may be transmitted--if,\nas Mr. Darwin held, there are various other structural modifications\ncaused by use and disuse which imply inheritance of this kind--if\nacquired characters are hereditary, as the Duke of Argyll believes; then\nthe area over which this factor of organic evolution operates is\nenormous. Not every muscle only, but every nerve and nerve-centre, every\nblood-vessel, every viscus, and nearly every bone, may be increased or\ndecreased by its influence. Excepting parts which have passive\nfunctions, such as dermal appendages and the bones which form the skull,\nthe implication is that nearly every organ in the body may be modified\nin successive generations by the augmented or diminished activity\nrequired of it; and, save in the few cases where the change caused is\none which conduces to survival in a pre-eminent degree, it will be thus\nmodified independently of natural selection. Though this factor can\noperate but little in the vegetal world, and can play but a subordinate\npart in the lowest animal world; yet, seeing that all the active organs\nof all animals are subject to its influence, it has an immense sphere.\nThe Duke of Argyll compares the claim made for this factor to \"some bit\nof Bumbledom setting up for Home Rule--some parochial vestry claiming\nindependence of a universal empire.\" But, far from this, the claim made\nfor it is to an empire, less indeed than that of natural selection, and\nover a small part of which natural selection exercises concurrent power;\nbut of which the independent part has an area that is immense.\n\nIt seems to me, then, that the Duke of Argyll is mistaken in four of the\npropositions contained in the passages I have quoted. The inheritance of\nacquired characters _is_ disputed by biologists, though he thinks it is\nnot. It is not true that \"heredity is the central idea of natural\nselection.\" The statement that natural selection includes and covers all\nthe causes which can possibly operate through inheritance, is quite\nerroneous. And if the inheritance of acquired characters is a factor at\nall, the dominion it rules over is not insignificant but vast.\n\n       *       *       *       *       *\n\nHere I must break off, after dealing with a page and a half of the Duke\nof Argyll's article. A state of health which has prevented me from\npublishing anything since \"The Factors of Organic Evolution,\" now nearly\ntwo years ago, prevents me from carrying the matter further. Could I\nhave pursued the argument it would, I believe, have been practicable to\nshow that various other positions taken up by the Duke of Argyll do not\nadmit of effectual defence. But whether or not this is probable, the\nreader must be left to judge for himself. On one further point only will\nI say a word; and this chiefly because, if I pass it by, a mistaken\nimpression of a serious kind may be diffused. The Duke of Argyll\nrepresents me as \"giving up\" the \"famous phrase\" \"survival of the\nfittest,\" and wishing \"to abandon it.\" He does this because I have\npointed out that its words have connotations against which we must be on\nour guard, if we would avoid certain distortions of thought. With equal\npropriety he might say that an astronomer abandons the statement that\nthe planets move in elliptic orbits, because he warns his readers that\nin the heavens there exist no such things as orbits, but that the\nplanets sweep on through a pathless void, in directions perpetually\nchanged by gravitation.\n\nI regret that I should have had thus to dissent so entirely from various\nof the statements made, and conclusions drawn, by the Duke of Argyll,\nbecause, as I have already implied, I think he has done good service by\nraising afresh the question he has dealt with. Though the advantages\nwhich he hopes may result from the discussion are widely unlike the\nadvantages which I hope may result from it, yet we agree in the belief\nthat advantages may be looked for.\n\n\nEND OF VOL. I.\n\n       *       *       *       *       *\n\n\nTranscriber's note\n\n\nThe following changes have been made to the text:\n\nPage 21: \"heterogeenity\" changed to \"heterogeneity\".\n\nPage 47: \"multipled results\" changed to \"multiplied results\".\n\nPage 59: \"pre-Raffaelites\" changed to \"pre-Raphaelites\".\n\nPage 84: \"heretogeneity\" changed to \"heterogeneity\".\n\nPage 94: \"observedcoexistences\" changed to \"observed coexistences\".\n\nPage 97: \"Cirrhipoedia\" changed to \"Cirrhipedia\".\n\nPage 108: \"prima facie\" changed to \"prima facie\".\n\nPage 112: \"a fortiori\" changed to \"a fortiori\".\n\nPage 124: \"irreconcileable\" changed to \"irreconcilable\".\n\nPage 140: \"some thing like double\" changed to \"something like double\".\n\nPage 216: \"representive\" changed to \"representative\".\n\nPage 291: \"inbibe\" changed to \"imbibe\".\n\nPage 306: \"whic hthey and living\" changed to \"which they and living\".\n\nPage 359: \"of the two races, not\" changed to \"of the two races, nor\".\n\nPage 393: \"parenthethic\" changed to \"parenthetic\".\n\nPage 411: \"hypertropic\" changed to \"hypertrophic\".","title":"Essays: Scientific, Political, & Speculative; Vol. 1 of 3: Library Edition (1891), Containing Seven Essays not before Republished, and Various other Additions.","tradition":"philosophy-ethics","translated_text":null,"word_count":158447}