I486 THE STORY OF THE UNIVERSE 



so perfectly adapted to each other and to the physi- 

 cal conditions under which they live, that none of 

 them could be still better adapted or improved; for 

 in all countries the natives have been so far conquered 

 by naturalized productions that they have allowed 

 some foreigners to take firm possession of the land. 

 And as foreigners have thus in every country beaten 

 some of the natives, we may safely conclude that the 

 natives might have been modified with advantage, so 

 as to have better resisted the intruders. 



As man can produce, and certainly has produced, a 

 great result by his methodical and unconscious means 

 of selection, what may not natural selection effect? 

 Ma can act only on external and visible characters: 

 Nature, if I may be allowed to personify the natural 

 preservation or survival of the fittest, cares nothing 

 for appearances, except in so far as they are 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, as is implied by the fact of their selection. 

 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 quadruped 

 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 inferior 



