12 CHARACTER OF DOMESTIC VARIETIES. [Cha?. L 



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 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 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 aborigi- 

 nally 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 

 much in determining what characters are of generic value ; all 

 such valuations being at present empirical. When it is explained 

 now 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 difference 

 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, 

 Woodhound, 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 us doubt about 

 the immutability of the many closely allied natural species — for 

 instance, of the many foxes — inhabiting different quarters of the 

 world. I do not believe, as we shall presently see, that the whole 



