124 EVOLUTION AND NATURAL THEOLOGY. 



mercial value for their breeding to be carefully 

 attended to (as the ass). 



The great variation which takes place among 

 domesticated species is of incalculable import- 

 ance to man. It is due entirely to the influence 

 of changed conditions of life, which allow a 

 few years of domestication to produce the 

 effect of centuries of Natural Selection, though 

 less permanently, as the process is too rapid to 

 allow of the tendency to reversion being bred 

 out. Upon this principle depends everything 

 which makes .agriculture, farming, gardening, 

 sporting, or any other occupation connected 

 with animals or plants an art or a sciene, rather 

 than a mere routine. 



Ponton has objected* that organisms are 

 modified under domestication not for their 

 own benefit, but for man's, and hence that such 

 variation is opposed to the main principle of 

 Natural Selection, which is that every species 

 shall be modified for its own advantage. But 

 he has overlooked the obvious fact that domes- 

 ticated species are not maintained by their own 

 strength, but by man's, and that therefore the 



* " The Beginning," p. 401. 



