It is wonderful that man, by deliberate choice in selecting the sires and dams, has been able to produce such widely-different races as the short-horn, the Highland and the Sussex breed, and not only to produce them, but to keep them there generation after generation. In Nature, no such deviations are allowed--her motto is “One species, one shape,” which is only relaxed so as to allow a few geographical varieties. It is man who makes all these strange breeds, just as he has made such a queer, irregular, varied lot of creatures from the human stock. Withdraw once and for all man’s guiding “intelligence,” or perversity, if you choose so to call it, and all these cattle would in a few hundred years revert to one form, nearly (but not quite) the same as that they came from. So, too, the Sheep; so, too, the Pigs. And man himself, if one could poison him universally with a mind-destroying microbe, would become a beautiful, healthy, silly creature, dying at first by millions annually, and at last represented by a hundred thousand unvarying specimens, inhabiting the warm but healthy corners of the earth, aimlessly happy, free from disease, neither increasing nor decreasing in number. It is legitimate, and is a means of examining the whole problem of man’s history, to inquire whether we have reason or not to suppose that, were intelligent man thus removed arbitrarily and completely from the scene, a new “lord of the world” would arise, by normal evolutionary process. A bird, an elephant, a rat, might give rise to the new line of progressive development, and, unchecked by man, once jealous and repressive, but now down-fallen, this new stock might acquire such brains and wits as we men now boast of, and people the earth. You never can tell! But it is not the business of science to expatiate on such possibilities.