FOOD A FACTOR I*t .EVOLUTION PROBLEM. 273 



necessarily entail extinction, unless it be food directly opposed 

 to the animal's nature ; and it raatters not if the change is 

 compulsory, for changes of taste may be either natural or cul- 

 tivated. For example, children relish food they cannot eat 

 when adult, and vice versa, which is natural ; and an appetite 

 for some foods may be cultivated at any age. Again, food 

 probably causes much of the change in tame boars and other 

 animals that become wild, and vice versa. Still it is not strictly 

 correct to say that the horse as such was ever carnivorous, for 

 an animal that was the common ancestor of so many diverse 

 animals was as much one as the other. 



In 1878, in a hastily written prospectus of a work that Dr. 

 C. D. House designed to publish, in conformity with his 

 (House's) views, I said the horse was probably once carnivor- 

 ous. Thinking Dr. House to be mistaken, I wrote to Dr. Leidy 

 of Philadelphia, asking his opinion on the subject. He agreed 

 with me. 



THE ORIGINAL HOME OF THE HORSE. 



THERE is \io doubt that the original home of the horse is not 

 Europe, but Central Asia ; for since the horse in its natural 

 state depends on grass for its nourishment and fleetness for its 

 weapon (safety), it could not in the beginning have thriven 

 and multiplied in the thick forest-grown territory of Europe. 

 Much rather should its place of propagation be sought in those 

 steppes where it still roams about in a wild state. Here too 

 arose the first nations of riders of which we have historic 

 knowledge, the Mongolians and the Turks, whose existence, 

 even at this day, is as it were combined with that of the horse. 

 From these regions the horse spread in all directions, especially 

 into the steppes of Southern and Southeastern Russia and into 

 Thrace, until it finally found entrance into the other parts of 

 Europe, but not until after the immigration of the people. 

 This assumption is at least strongly favored by the fact that 

 the further a district of Europe is from those Asiatic steppes, 

 i.e., from the original home of the horse, the later does the 

 tamed horse seem to have made its historic appearance in it. 

 The supposition is further confirmed by the fact that horse- 



