154 THE HISTORY OF CHEATION. 



Tlie farmer wishing to breed a special race of animals, for 

 example, a kind of sheep distinguished by particularly fine 

 wool, proceeds in the same manner. The only process 

 applied in the improvement of wool consists in this, that the 

 farmer with the greatest care and perseverance selects from 

 a whole flock of sheep those individuals which have the 

 finest wool. These only are used in breeding, and among 

 the descendants of these selected sheep, those again are 

 chosen which have the finest wool, etc. If this carefal 

 selection is carried on through a series of generations, the 

 selected breeding-sheep are in the end distinguished by a 

 wool which differs very strikingly from the wool of the 

 original parent, and this is exactly the advantage which 

 the breeder desired. 



The difierences of the individuals that come into considera- 

 tion in this artificial selection are very slight. An ordinary 

 unpractised man is unable to discover the exceedingly 

 minute differences of individuals which a practised breeder 

 perceives at the first glance. The business of a breeder is 

 not easy; it requires an exceedingly sharp eye, great 

 patience, and an extremely careful manner of treating the 

 organisms to be bred. In each individual generation, the 

 differences of individuals are perhaps not seen at aU by the 

 uninitiated ; but by the accumulation of these minute 

 differences during a series of generations, the deviation from 

 the original form becomes in the end very gTeat. It becomes 

 so great that the artificially produced form may in the end 

 differ far more from the original form than do two so- 

 called "good species" in their natural state. The art of 

 breeding has now made such progress, that man can often at 

 discretion produce certain peculiarities in cultivated species 



