124 SPECIES NOT 



ations of the same or assumed species to prove a 

 great theory, which he has raised, of the community 

 of origin of all species. In one case the fact of 

 the variation is admitted, as in the Swedish 

 and the common turnip; or the descendants 

 and varieties of the rock dove under domestica- 

 tion; to which may be added all our domestic 

 cattle and garden productions. In the other case 

 it is not only not admitted, but believed by 

 naturalists to be impossible. 



Thus, Mr. Darwin talks of analogous variations 

 of the fancy pigeon, as breeding back to the rock 

 dove, their supposed ancestor. But this goes 

 no way to prove the supposition that an eairlc 

 and a pigeon had the same origin. And because 

 the ass has sometimes transverse bars on its 

 legs, like the zebra, or the dun horse the same 

 bars on its legs, or a double shoulder stripe on 

 its shoulder, is Mr. Darwin justified from this 

 in saying, as he does, that the zebra, the horse, 

 and the ass have had the same origin? Why 

 does he not adopt the much more probable theory, 

 that being members of the same genus, and having 

 their nutritive organs upon the same type, there 

 may be in each a tendency to a similar deposit of 

 pigment in similar structures. That it is highly 

 exceptional Mr. D. does not deny. But he may, 

 if he chooses, claim a common origin for the 

 zebra and the ass, which would at once account 

 for his exceptional cases of sporting back in the 

 latter. But then I meet him with the question, 

 Does the produce of the ass and the zebra breed? 



