18 CHARACTEE OF DOMESTIC VARIETIES. [Chap. I. 



Character of Domestic Varieties; difficulty of dis- 

 tinguishing between Varieties and 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 domestic race, as already remarked, less uniformity 

 of character than in true species. Domestic races often 

 have a somewhat monstrous character ; by which I 

 mean, that, although differing 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 decree. 

 This must be admitted as true, for the domestic races 

 of many animals and plants have been ranked by some 

 competent 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 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 



