COSMIC PHILOSOPHY 



differ so widely from their parent-forms that, 

 if found in a state of nature, they would be un- 

 hesitatingly classified as distinct species, and 

 sometimes as distinct genera. Modifications in 

 the specific characters of domesticated organisms 

 are the only ones which take place so rapidly 

 that we can actually observe them ; and it there- 

 fore becomes highly important to inquire what 

 is the agency which produces these modifica- 

 tions. 



That agency is neither more nor less than 

 selection^ taking advantage of that slight but uni- 

 versal variation in organisms implied by the 

 fact that no two individuals in any species are 

 exactly alike. If man, for example, wishes to 

 produce a breed of fleet race-horses, he has 

 only to take a score of horses and select from 

 these the fleetest to pair together : from among 

 the offspring of these fleet pairs he must again 

 select the fleetest ; and thus, in a few genera- 

 tions, he will obtain horses whose average speed 

 far exceeds that of the fleetest of their undo- 

 mesticated ancestors. It is in this and no other 

 way that our breeds of race-horses have been 

 produced. In this way too have been produced 

 the fine wools of which our clothing is made. 

 By selecting, generation after generation, the 

 sheep with the finest and longest wool, a breed 

 of sheep is ultimately reared with wool almost 

 generically different from that of the undomes- 



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