188 THE LESSON OF EVOLUTION 



Fission and amphimixis may both be true causes 

 of variation, but they are of minor importance. 

 They may ring changes on the old characters but 

 they cannot introduce anything new. Use and 

 physiogenesis are also true causes, and their action 

 on the germ-cells is explained by Bering's theory ; 

 but they are far from being sufficient to account for 

 all variations, and we must call in the aid of psycho- 

 genesis to explain a very large number of facts. The 

 organic units, biophores, plastidules whatever we 

 may call them are drafted off by mental action, and, 

 when they grow, they develop as memory compels 

 them to do. Variations directly produced by outside 

 physical agencies are rarely transmitted ; it is chiefly 

 the so-called indirectly-acquired variations which are 

 transmitted. But indirect variation is only another 

 name for adaptation. These cannot be due directly 

 to the environment. They are helped forward by 

 natural selection, but they are initiated by psycho- 

 genesis. 



The variations that arise are partly definite and 

 partly indefinite. The indefinite variations may be 

 due to fission, amphimixis, or to physiogenesis, when 

 the action is irregular. Definite variation is caused 

 oy use, by psychogenesis, or by physiogenesis, when 

 the action is regular and long continued ; and per- 



principle of consciousness to all organic life, and to find 

 even among the lower plants something which corresponds 

 to it. Such an expansion of consciousness to all organic 

 life is, however, too crude and unintelligible to take its 

 place in our general conception of nature." He does not, 

 however, explain why this view is crude or even unin- 

 telligible. 



