THE THEORY OF NATURAL SELECTION. 29 1 



man at the same time prevents the law of natural selection 

 from rigidly exterminating those individuals which happen 

 to be born with variations which would be hurtful to the 

 species in a wild state. The fact that domesticated 

 animals exhibit peculiarities which are in no way adapta- 

 tions to their natural surroundings, but which are mere 

 adaptations to man's wants or tastes, is explained by 

 'artificial selection.' Man, namely, has as regards each 

 domestic animal an ideal of what he wants. It may be 

 that he has no consciousness of having any such ideal 

 before him, but it may be taken as certain that he 

 possesses it nevertheless. * Artificial selection ' consists 

 essentially in the choice which man exercises as to the 

 young of his domestic animals, in respect to which he 

 will allow to live, and which he will destroy. In the case 

 of the young of each of his domesticated animals, a man 

 sees some individuals having peculiarities which he thinks 

 will be useful to him, or which come nearest to the ideal 

 which he has formed of the animal, or of what the animal 

 ought to be. Such individuals he keeps, and permits to 

 have offspring; so that the peculiarities which induced 

 him to keep these individuals are perpetuated and handed 

 down to future generations, becoming in the process 

 intensified. On the contrary, all those individuals amongst 

 the young, which do not conform to man's ideal standard 

 of perfection, are either killed off on the spot, or are, at 

 any rate, prevented from leaving offspring behind them. 

 In this way, by a long-continued process of selecting the 

 particular individuals which he will allow to live and to 

 breed, man has succeeded in producing the numerous 

 domesticated varieties of animals. In the case of savage 



