The Making of Species 



protoplasm a growth-force, which makes each 

 organism in itself a force making towards pro- 

 gressive evolution. He holds that animals and 

 plants would have become much as they are now 

 even if no struggle for existence had taken place. 

 "To the believers in this kind of ... ortho- 

 genesis," writes Kellog {Darwinism To-day, p. 

 278), " organic evolution has been, and is now, 

 ruled by unknown inner forces inherent in organ- 

 isms, and has been independent of the influence 

 of the outer world. The lines of evolution are 

 immanent, unchangeable, and ever slowly stretch 

 toward some ideal goal." It is easy to enunciate 

 such a theory, impossible to prove it, and difficult 

 to disprove it. 



It seems to us that the fact that, so soon as 

 organisms are removed from the struggle for 

 existence, they tend to degenerate, is a sufficient 

 reason for refusing to accept theories of the 

 description put forth by Naegeli. More truly 

 Lamarckian is Eimer's theory of orthogenesis, 

 according to which it is the environment which 

 determines the direction which variation takes ; 

 and the variations which are induced by the 

 environment are transmitted to the offspring. 



Spencer and Orr preach nearly pure Lamarck- 

 ism. The former, while fully recognising the 

 importance of natural selection, considered that 

 sufficient weight has not been given to the 

 effects of use and disuse, or to the direct action 



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