Although the physical and mental educability of animals when brought into companionship with man is an old subject of remark, and one of the most interesting features which they exhibit, it was not until the doctrine of descent by variation of species from other related forms became established, that we had a chance to see the vast possibilities of accomplishment which are presented to us by our domesticated creatures. It is true that the breeder's art is old and that men have felt the subjugated animals to be almost like clay in the potter's hands, but except in a small and rather careless way with the dogs, little attention has been given to the development of the intelligence of these captives. The success which we have obtained with this animal has been accomplished by a selective process, but one which has been almost as blind in its operation as the choice which acts in the natural world. For thousands of years men have preferred the dogs which manifested a sympathy with them, and the result is a creature which, though derived from a very brutal ancestry, has in its way as intense affections as human beings. Now and then they have chosen deliberately to develop some mental peculiarity of the animal which would be of service in hunting, and the effect of this care is to be noted in the considerable variety and perfection of mental development which the sporting dogs exhibit. In the main, however, the interest of our dog fanciers has been limited to the physical features of the species; nothing like a deliberate effort to ascertain how far the development of their mental parts could be carried has ever been essayed. In no other field of human endeavor of anything like equal importance has there been so little understanding applied to the tasks. Now that we are beginning to know something of the laws of inheritance, it is high time for us deliberately to consider what our relations to the organic world are hereafter to be, and how we can guide ourselves in these relations by the light of modern learning. It is in the first place clear that the subjugation of the earth which necessarily accompanies the development of civilization, inevitably tends to sweep away a large part of the organic life which is not adopted and protected by man. Already, with the mere beginnings of this culture, we find that several of the large beasts and birds and a number of plants have been destroyed. New as civilization is on this continent, it has already brought the moose and the buffalo to a point where they are on the verge of extinction, and in the Old World the wild ancestors of the horse and the bull have quite disappeared from the wildernesses. Within a few centuries the greater birds, the Dinornis and Epiornis, as well as the interesting Dodo, have vanished from the southern isles which they inhabited. In the century to come we can foresee that this process of effacement of the ancient life will go on with accelerated velocity.