14 CHARACTER OF DOMESTIC VARIETIES. 



eties. If any well-marked distinction existed between a 

 domestic race and a species, this source of doubt would not 

 so perpetually recur. It has often been stated that domestic 

 races do not differ from each other in characters of generic 

 value. It can be shown that this statement is not correct ; 

 but naturalists differ much in determining what characters 

 are of generic value ; all such valuations being at present 

 empirical. When it is explained how genera originate under 

 nature, it will be seen that we have no right to expect often 

 to find a generic amount of difference in our domesticated 

 races. 



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 offspring of any single species, then such 

 facts would have great weight in making ns doubt about the 

 immutability 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 domesti- 

 cation ; 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 domes- 

 tication animals and plants having an extraordinary inherent 

 tendency to vary, and likewise to withstand diverse cli- 

 mates. I do not dispute that these capacities have added 

 largely to the value of most of our domesticated produc- 

 tions ; but how could a savage possibly know, when he first 

 tamed an animal, whether it would vary in succeeding 

 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 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 



