From the Unconscious to the Conscious 



scale they see a continuous and intentional effort towards 

 adaptation. 



Nageli is still more precise: according to him the 

 organism includes two kinds of plasm: the nutritive, 

 common to all species and not differentiated; and the 

 specific, or idio-plasm. 



This idio-plasm would contain not only the micellian 

 fasciculi which characterise it, but also an internal 

 evolutionary tendency with all the capacities and poten- 

 tialities for transformation and perfectibility. This 

 potentiality must have existed in the first living forms 

 from the very beginnings of life. External factors hence- 

 forth would only facilitate adaptation; but would of 

 themselves be incapable of initiating evolution. They 

 would but aid and favour evolution, and bring it under 

 their special rhythm. 



These concepts of Nageli's are extremely interesting. 

 They eventuate in the conclusion that evolution has 

 come about, not by the influence of the environment, 

 but conformably to it. 



Adaptation appears in all cases as a consequence, 

 sometimes as a determining factor, but never as a 

 sufficient and essential cause. 



An impartial study of the modifications which 

 originate species leads necessarily to this conclusion. 

 But such a concept is absolutely contrary to classical 

 naturalism. 



