THERE are few people who have not heard of the Mac Carthies - one of the real old Irish families, with the true Milesian blood running in their veins, as thick as buttermilk. Many were the clans of this family in the south; as the Mac Carthy-more - and the Mac Carthy-reagh - and the Mac Carthy of Muskerry; and all of them were noted for their hospitality to strangers, gentle and simple. But not one of that name, or of any other, exceeded Justin Mac Carthy, of Ballinacarthy, at putting plenty to…