CHAP. I.] CHARACTER OF DOMESTIC VARIETIES. 11 



some of their characters to ancestral forms, it seems to me not im- 

 probable that if we could succeed in naturalising, or were to culti- 

 vate, during many generations, the several races, for instance, of 

 the cabbage, in veiy 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, whilst kept 

 under the same conditions, and whilst 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 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 esculent 

 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 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 cf 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 differ- 

 ences 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 



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