14 CHARACTER OF DOMESTIC VARIE2IEB, 



could not breed our cart and race-horses, long and short- 

 horned cattle, and poultry of various breeds, and esculent 

 vegetables, for an unlimited number of generations, would 

 be opposed to all experience. 



CHARACTER OF DOMESTIC VARIETIES; DIFFICULTY OF DIS- 

 TIXGUISHIXG BETWEEJ^ VARIETIES AXD SPECIES; 

 ORIGIN" OF DOMESTIC VARIETIES FROM ONE OR MORE 

 SPECIES. 



When we look to the hereditary varieties or races of our 

 domestic animals and plants, and compare them with 

 closely allied species, we generally perceive in each domes- 

 tic race, as already remarked, less uniformity of character 

 than in true species. Domestic races often have a some- 

 what monstrous character ; by which I mean, that, 

 although dillering from each other and from other species 

 of the same genus, in several trifling respects, they often 

 differ in an extreme degree in some one part, both when 

 compared one with another, and more especially when 

 compared with the species under nature to which they are 

 nearest allied. With these exceptions (and with that of 

 the perfect fertility of varieties when crossed — a subject 

 hereafter to be discussed), domestic races of the same 

 species differ from each other in the same manner as do 

 the closely allied species of the same genus in a state of 

 nature, but the differences in most cases are less in degree. 

 This must be admitted as true, for the domestic races of 

 many animals and plants have been ranked by some com- 

 petent judges as the descendants of aboriginally distinct 

 species, and by other competent judges as mere varieties. 

 If any well marked distinction existed between a domestic 

 race and a species, this source of doubt would not so per- 

 petually recur. It has often been stated that domestic races 

 do not differ fi'om each other in characters of generic value. 

 It can be shown that this statetnent is not correct; but 

 naturalists differ much in determing 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. 



