306 THE WHENCE AND THE WHITHER OF MAN 



degeneration of muscles in hand and foot go on side 

 by side, because some are used and some are disused. 

 Centres of use and disuse must be centres of evolution. 

 And there would be as many distinct centres of evo- 

 lution in different parts of the body as there were 

 centres of use and disuse. And between these centres 

 there might be no correlation except that of use and 

 disuse. Brain, muscles, and jaws would develop simul- 

 taneously in the ancestors of insects. And the effects 

 of use and disuse, transmitted through a series of 

 generations, would be cumulative. The species ad- 

 vances rapidly because all its members have in gen- 

 eral the same habits; the same parts are advancing 

 or degenerating, although at different rates, in all its 

 individuals. An animal having an organ highly de- 

 veloped is far less likely to pair with one having a 

 lower development of the same organ. The Neo- 

 Lamarckian theory supplies thus what is lacking in 

 the Neo-Darwinian. 



In lower forms, like hydra, of simple structure and 

 comparatively few possibilites of variation, natural 

 selection is dominant. In higher forms, like verte- 

 brates, and especially in man, it is of decidedly sub- 

 ordinate value as a promoter of evolution. For man, 

 as we have seen, is a marvellously complex being. 

 The great difficulty in his case is not so much to 

 quickly gain new and favorable variations as to keep 

 all the organs and powers of the body steadily advanc- 

 ing side by side. Natural selection has in man the 

 important but subordinate position of the judge in a 

 criminal court, to pronounce the death verdict on the 

 hopeless and incorrigible. 



Both Neo-Darwinians and Neo-Lamarckians have 



