14 DEGENERATION I I 



of " natural selection " flashed upon him. That idea 

 is as follows. Not only among mankind, but far more 

 largely among other kinds of animals and among 

 plants, the number of offspring produced by every pair 

 is immensely in excess of the available amount of the 

 food appropriate to the particular species in question. 

 Accordingly, there is necessarily a struggle for exist- 

 ence a struggle among all those born for the posses- 

 sion of the small quantum of food. The result of this 

 struggle is to pick out, or select, a few who survive 

 and propagate the species, whilst the majority perish 

 before reaching maturity. The fact that no two 

 members of a species are alike has already been 

 shown to be the starting-point which enables the 

 breeder to make his selection. So, too, with natural 

 selection in the struggle for existence ; the fact that 

 all the young born of one species are not exactly 

 alike but some larger, some smaller, some lighter, 

 some darker, some short-legged, some big-eyed, some 

 long-tongued, some sharp-toothed, and so on furnishes 

 the opportunity for a selection. Those varieties which 

 are best fitted to obtain food and to baffle their com- 

 petitors, gain the food and survive, the rest perish. 



We have, then, to note that the hypothesis that 

 there must be a selection which was framed or de- 

 duced as a " test hypothesis " from the earlier hypo- 

 thesis that species have arisen by the action of causes 

 still competent to produce new forms led Mr. Darwin 

 to the discovery of this great cause the "natural 

 selection," or " survival of the fittest," in the struggle 

 for existence. Just as the breeder can slowly change 



