Chap. I.] VARIATION UNDER DOMESTICATION. 17 



state. In many cases we do not know what the aho- 

 riginal stock was, and so could not tell whether or not 

 nearly perfect reversion had ensued. It would he neces- 

 sary, in order to prevent the effects of intercrossing, 

 that only a single variety should have heen turned 

 loose in its new home. Nevertheless, as our varieties 

 certainly do occasionally revert in some of their charac- 

 ters to ancestral forms, it seems to me not improbable 

 that if we could succeed in naturalising, or were to 

 cultivate, during many generations, the several races, 

 for instance, of the cabbage, in very poor soil (in which 

 case, however, some efiEect 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 argu- 

 ment; 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 con- 

 siderable 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. 



