Until recently it was thought that all the evidence which could be brought to bear on the matter pointed to a separate origin of the Dog. It was argued, for instance, that as we have evidences of distinct breeds existing in far-back periods of the world’s history, there was actually no time, prior to those periods, for him to have diverged from a savage ancestor, such as a Wolf or a Jackal. It was also thought highly unlikely that a number of primitive races of man should have separately tamed different wild _Canidæ_. Mr. Youatt, one of our best authorities on the Dog, writing in 1845, says: “This power of tracing back the Dog to the very earliest periods of history, and the fact that he then seemed to be as sagacious, as faithful and as valuable as at the present day, strongly favours the opinion that he descended from no inferior and comparatively worthless animal; that he was not the progeny of the Wolf, the Jackal, or the Fox; but he was originally created, somewhat as we now find him, the associate and friend of man.” [Illustration: SKULL OF YOUNG DOG.] A few years ago there was no gainsaying arguments such as these, for then nearly everybody believed that the world was literally only six thousand years old, and that species were absolutely unchangeable. But Sir Charles Lyell and Mr. Darwin have “_changé tout cela_.” The argument from time fails utterly, and other facts have to be taken into consideration. There is, first of all, the fact of identity of structure. There is absolutely no definition framable which will include all the varieties of the domestic Dog, and exclude all the wild species--none even which will include all the Dogs properly so called, both wild and tame, and at the same time exclude the Wolf and Jackal. It is the same as regards habits, instincts, mental endowments, &c. Wolves and Jackals can be and have been tamed. Domestic Dogs can become, and have again and again become, wild, and in no way better than true aborigines; and to assert that the Dog is not descended from a Jackal because his manners and customs are better, his tail more curly, and his voice a bark instead of a howl, is about as just as to assert that Englishmen cannot possibly be descended from ancient Britons, because they wear clothes instead of a coating of blue paint. [Illustration: HARE INDIAN DOG.]