CHARACTER OF DOMESTIC VARIETIES 33 



check, by blending together, any slight deviations in their 

 structure, in such case, I grant that we could deduce nothing 

 from domestic varieties in regard to species. But there is 

 not a shadow of evidence in favour of this view : to assert 

 that we could not breed our cart- and race-horses, long- and 

 short-horned cattle, and poultry of various breeds, and escu- 

 lent vegetables, for an unlimited number of generations, 

 would be opposed to all experience. 



CHARACTER OF DOMESTIC VARIETIES; DIFFICULTY OF 



DISTINGUISHING 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 mon- 

 strous 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 an- 

 other, 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), domes- 

 tic 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 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; 



B— HC XI 



