Natural Selection, or the Survival of the Fittest, as affecting domestic productions.–We know little on this head. But as animals kept by savages have to provide their own food, either entirely or to a large extent, throughout the year, it can hardly be doubted that, in different countries, varieties differing in constitution and in various characters would succeed best, and so be naturally selected. Hence perhaps it is that the few domesticated animals kept by savages partake, as has been remarked by more than one writer, of the wild appearance of their masters, and likewise resemble natural species. Even in long-civilised countries, at least in the wilder parts, natural selection must act on our domestic races. It is obvious that varieties, having very different habits, constitution, and structure, would succeed best on mountains and on rich lowland pastures. For example, the improved Leicester sheep were formerly taken to the Lammermuir Hills; but an intelligent sheep-master reported that “our coarse lean pastures were “unequal to the task of supporting such heavy-bodied sheep; “and they gradually dwindled away into less and less bulk: “each generation was inferior to the preceding one; and when “the spring was severe, seldom more than two-thirds of the “lambs survived the ravages of the storms.” So with the mountain cattle of North Wales and the Hebrides, it has been found that they could not withstand being crossed with the larger and more delicate lowland breeds.