CHARAOTEB OF DOMESTIC VARIETIES. 15 



In attempting to estimate the amount of structural dif- 

 ference between allied domestic races, we are soon involved 

 in doubt, from not knowing whether they are descended 

 from one or several parent species. This point, if it could 

 be cleared up, would be interesting; if, for instance, it 

 could be shown that the greyhound, bloodhound, terrier, 

 spaniel and bull-dog, which we all know propagate their kind 

 truly, were the ofispring of any single species, then such 

 facts would have great weight in making us doubt about 

 the inimutability of the many closely allied natural species 

 — for instance, of the many foxes — inhabiting the different 

 quarters of the world. I do not believe, as we shall pres- 

 ently see, that the whole amount of difference between the 

 several breeds of the dog has been produced under domes- 

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

 to their being descended from distinct 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 do- 

 mestication animals and plants having an extraordinary 

 inherent tendency to vary, and likewise to withstand 

 diverse climates. I do not dispute that these capacities 

 have added largely to the value of most of our domesticated 

 productions; but how could a savage possibly know, when 

 he first tamed an animal, whether it would vary in suc- 

 ceeding generations, and whether it would endure 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, prevented their domesti- 

 cation? 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 largely as the parent 

 species of our existing domesticated productions have 

 varied. 



In the case of most of our anciently domesticated animals 

 and plants, it is not possible to come to any definite con- 

 clusion, whether they are descended from one or several 

 wild-species. The argument mainly relied on by those who 



