32 DARWINISM AND THE PROBLEMS OF LIFE 



Now, all these different races are not originally 

 independent. It is man who has taken a few primitive 

 types and changed them by selection. In the case of 

 the pigeon it is certain that all the various races descend 

 from one primitive form, the rock pigeon, which is 

 distinguished by black bands on the wings. We see 

 how these modifications can be brought about in the 

 actions of breeders, who are always bringing out new 

 races. They do not accomplish this by crossing; no 

 new characteristics can be produced in that way, but 

 only the existing ones mixed and distributed. Breeders 

 act otherwise. They select from the offspring of a 

 couple the animal that shows a slight trace of the 

 feature that they wish to produce. Thus, if they desire 

 to create a race of dogs with long legs (and there are 

 prizes offered by breeding societies for such objects), 

 they choose one pup from the litter that has longer legs 

 than its brothers and sisters. This is paired with a dog 

 from another litter with specially long legs, and the 

 same selection is made again amongst their pups. This 

 is continued until they get a race of dogs with legs of 

 the required length. The object is attained by the 

 accumulation of insignificantly small variations. 



According to Darwin, Nature acts in this way, only 

 on a higher scale. It selects, not only in the interest 

 of one characteristic, but of a number simultaneously. 

 So in the case of the hares, to return to our illustration, 

 it is not merely a question of making them swifter than 

 their enemies, but also of furnishing them with sharp 

 senses, and a higher intelligence to use in choosing 

 places of security. Finally, they must have no con- 



