CHARACTER OF DOMESTIC VARIETIES. 13 



races, for instance, of the cabbage, in very poor soil — in. 

 which case, however, some effect would have to be attributed 

 to the definite action of the poor soil — that they would, to 

 a large extent, or even wholly, revert to the wild aboriginal 

 stock. Whether or not the experiment would succeed is not 

 of great importance for our line of argument ; for by the 

 experiment itself the conditions of life are changed. If it 

 could be shown that our domestic varieties manifested a 

 strong tendency to reversion — that is, to lose their acquired 

 characters, while kept under the same conditions and while 

 kept in a considerable body, so that free intercrossing might 

 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 favor 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 J DIFFICULTY OF DIS- 

 TINGUISHING BETWEEN VARIETIES AND SPECIES J 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 

 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 varie- 

 ties 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 aboriginally 

 distinct species, and by other competent judges as mere vari- 



