222 The Process of Selection 



is in many ways highly specialized ; and a high degree 

 of specialization tends to limit further evolution — the 

 balance of an intricate organization will not admit of 

 any great change. No doubt there are some parts of 

 man's body that are not highly specialized, the hand 

 being a notable example. It is a generalized hand 

 compared with a horse's hoof, or a bat's wing, or a 

 mole's shovel, or a whale's nipper. Why, then, should 

 we not find signs of evolution in man's hand? The 

 answer must be in part this, that for man's purpose 

 a generalized hand is far and away the best. It is a 

 universal tool with which man can do a hundred 

 things well. 



In the ordinary course of Nature advantageous 

 variations or novelties have a good chance of per- 

 sisting. When they come, they come to stay. Profes- 

 sor Punnett has calculated that "if a population 

 contains .001 per cent, of a new variety, and if that 

 variety has even a 5 per cent, selection advantage 

 over the original form, the latter will almost com- 

 pletely disappear in less than a hundred genera- 

 tions." This is in Wild Nature. Why does it not con- 

 tinue to occur in mankind ? Because man has rebelled 

 against Nature's method of drastic sifting for health, 

 vigor, and efficiency. By many artificial devices he 

 has brought it about that valuable new departures 

 (in artistic talent, for instance) do not find their 

 due reward, whereas deteriorative changes (extreme 

 short sight, for instance) are not visited with their 

 natural penalties. This is probably the deepest 



