VARIATION UNDER DOMESTICATION 43 



ing; if, for instance, it could be shown that the grey- 

 hound, bloodhound, terrier, spaniel, and bull-dog, which 

 we all know propagate their kind truly, were the off- 

 spring of any single species, then such facts would have 

 great weight in making us doubt about the immutability 

 of the many closely allied natural species — for instance, 

 of the many foxes — inhabiting different quarters of the 

 world. I do not believe, as we shall presently see, 

 that the whole amount of difference between the several 

 breeds of the dog has been produced under domestica- 

 tion; I believe that a small part of the difference is due 

 to their being descended Jrom ^istinct species. In the 

 case of strongly marked races of some other domesticated 

 species, there is presumptive or even strong evidence 

 that all are descended from a single wild stock, 



. It has often been assumed that man has chosen for 

 domestication animals and plants having an extraordinary 

 inherent tendency to vary, and likewise to withstand di- 

 verse climates. I do not dispute that these capacities 

 have added largely to the value of most of our domes- 

 ticated productions; but how could a savage possibly 

 know, when he first tamed an animal, whether it would 

 vary in succeeding generations, and whether it would en- 

 dure other climates ? Has the little variability of the ass 

 and goose, or the small power of endurance of warmth 

 by the reindeer, or of cold by the common camel, pre- 

 vented their domestication ? I cannot doubt that if other 

 animals and plants, equal in number to our domesticated 

 productions, and belonging to equally diverse classes and 

 countries, were taken from a state of nature, and could 

 be made to breed for an equal number of generations 

 under domestication, they would on an average vary as 



