Chap. IV. NATURAL SELECTION. 83 



them could anyhow be improved ; for in all countries, 

 the natives have been so far conquered by naturalised 

 productions, that they have allowed foreigners to take 

 firm possession of the land. And as foreigners have 

 thus everywhere beaten some of the natives, we may 

 safely conclude that the natives might have been mo- 

 dified with advantage, so as to have better resisted such 

 intruders. 



As man can produce and certainly has produced a 

 great result by his methodical and unconscious means 

 of selection, what may not nature effect ? Man can act 

 only on external and visible characters : nature cares 

 nothing for appearances, except in so far as they may 

 be useful to any being. She can act on every internal 

 organ, on every shade of constitutional difference, on the 

 whole machinery of life. Man selects only for his own 

 good ; Nature only for that of the being which she tends. 

 Every selected character is fully exercised by her ; and 

 the being is placed imder well-suited conditions of life. 

 Man keeps the natives of many climates in the same 

 country; he seldom exercises each selected character 

 in some peculiar and fitting manner ; he feeds a long 

 and a short beaked pigeon on the same food; he 

 does not exercise a long-backed or long-legged qua- 

 druped in any peculiar manner ; he exposes sheep 

 with long and short wool to the same climate. He 

 does not allow the most vigorous males to struggle 

 for the females. He does not rigidly destroy all in- 

 ferior animals, but protects during each varying season, 

 as far as lies in his power, all his productions. He 

 often begins his selection by some half-monstrous form ; 

 or at least by some modification prominent enough to 

 catch his eye, or to be plainly useful to lihn. Under 

 nature, the slightest difference of structure or consti- 

 tution may well turn the nicely-balanced scale in the 



