12 CHARACTER OF DOMESTIC VARIETIES. [CHAP. 



statement is not correct ; but naturalists differ much in determining 

 what characters are of generic value ; all such valuations being 

 present empirical. When it is explained how genera originate unde 

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

 a generic amount of difference in our domesticated races. 



In attempting to estimate the amount of structural differenc 

 between allied domestic races, we are soon involved in doubt, froi 

 not knowing whether they are descended from one or several parei 

 species. This point, if it could be cleared up, would be interesting ; 

 if, for instance, it could be shown that the greyhound, bloodhounc 

 terrier, spaniel, and bull-dog, which we all know propagate theii 

 kind truly, were the offspring of any single species, then such fa 

 would have great weight in making us doubt about the immut 

 bility of the many closely allied natural species for instance, 

 the many foxes inhabiting different quarters of the world. I 

 not believe, as we shall presently see, that the whole amount 

 <Ufference between the several breeds of the dog has been produc 

 under domestication ; I believe that a small part of the differenc 

 is due to their being descended from distinct species. In the 

 of strongly marked races of some other domesticated species, the 

 is presumptive or even strong evidence, that all are descended froi 

 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 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 succeeding 

 generations, and whether it would endure other climates ? Has tho 

 little variability of the ass and goose, or the small power of endur- 

 ance 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 produc- 

 tions, 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 cai 

 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 conclusion, whether 

 they are descended from one or several wild species. The argu- 

 ment mainly relied on by those who believe in the multiple origin 

 of our domestic animals is, that we find in the most ancient times, 

 on the monuments of Egypt, and in the lake-habitations of Switzer- 

 land, much diversity in the breeds ; and that some of- these ancient j 

 breeds closely resemble, or are even identical with, those still exist- 



