26 DABWINIAHTA. 



ing conditions in Nature. We separate and protect a 

 favorite race against its foes or its competitors, and 

 thus learn what it might become if Nature ever afford- 

 ed it equal opportunities. Even when, to subserve 

 human uses, we modify a domesticated race to the 

 detriment of its native vigor, or to the extent of prac- 

 tical monstrosity, although we secure forms which 

 would not be originated and could not be perpetuated 

 in free Nature, yet we attain wider and juster views 

 of the possible degree of variation. We perceive that 

 some species are more variable than others, but that 

 no species subjected to the experiment persistently 

 refuses to vary ; and that, when it has once begun to 

 vary, its varieties are not the less but the more sub- 

 ject to variation. u No case is on record of a variable 

 being ceasing to be variable under cultivation." It 

 is fair to conclude, from the observation of plants and 

 animals in a wild as well as domesticated state, that 

 the tendency to vary is general, and even universal. 

 Mr. Darwin does " not believe that variability is an 

 inherent and necessary contingency, under all circum- 

 stances, with all organic beings, as some authors have 

 thought." No one supposes variation could occur 

 under all circumstances ; but the facts on the whole 

 imply a universal tendency, ready to be manifested 

 under favorable circumstances. In reply to the 

 assumption that man has chosen for domestication 

 animals and plants having an extraordinary inherent 

 tendency to vary, and likewise to withstand diverse 

 climates, it is asked : 



" ITow could a savage possibly know, when lie first tamed 

 an animal, whether it would vary in succeeding generations, 



