VARIATION UNDER DOMESTICATION 11 



ance of the peculiarity, and not to the primary cause which may 

 have acted on the ovules or on the male element; in nearly the 

 same manner as the increased length of the horns in the offspring 

 from a short-horned cow by a long-horned bull, though appearing 

 late in life, is clearly due to the male element. 



Having alluded to the subject of reversion, I may here refer to 

 a statement often made by naturalists — namely, that our domestic 

 varieties, when run wild, gradually but invariably revert in char- 

 acter to their aboriginal stock. Hence it has been argued that no 

 deductions can be drawn from domestic races to species in a state 

 of nature. I have in vain endeavored to discover on what decisive 

 facts the above statement has so often and so boldly been made. 

 There would be great difficulty in proving its truth : we may safely 

 conclude that very many of the most strongly marked domestic 

 varieties could not possibly live in a wild state. In many cases we 

 do not know what the aboriginal stock was, and so could not tell 

 whether or not nearly perfect reversion had ensued. It would be 

 necessary, in order to prevent the effects of intercrossing, that 

 only a single variety should have been turned loose in its new 

 home. Nevertheless, as our varieties certainly do occasionally re- 

 vert in some of their characters to ancestral forms, it seems to me 

 not improbable that if we could succeed in naturalizing, or were to 

 cultivate, during many generations, the several 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 as- 

 sert 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 op- 

 posed to all experience. 



