ACTION OF EXTERNAL INFLUENCES. HI 



Moreover, in the sphere of sex, electric(?) attrac- 

 tions and repulsions co-operate between the idio- 

 plasmic determinants to produce phylogenetic varia- 

 tions. 



The adaptations of the fully developed organism, 

 which are the results of external influences, con- 

 sist either only of a specific molecular character 

 (irritability), by virtue of which the individual is 

 capable of responding to those influences with tem- 

 porary or permanent phenomena, or they consist of 

 finished arrangements. The latter have, in general, 

 a double function : either they protect the organism 

 from external influences whose results they are, or 

 they place it in a condition to apply such environ- 

 mental influences to their advantage. The prepon- 

 derance of the one or the other led to the develop- 

 ment of the plant or the animal kingdom. In the 

 one case the primordial plasma formed in the cellu- 

 lose cell wall a stimulus-proof covering. On account 

 of this cell membrane being insensible to stimuli, 

 adaptations in the plant kingdom were restricted 

 essentially to the spheres of nutrition and reproduc- 

 tion. In the other case the irritability and mobility 

 of the primordial plasma increased so that it was 

 placed in a condition to avoid the irritant or make it 

 serviceable by accommodating itself to it. The 

 cells sensible to irritants led in the animal kingdom 

 to the formation of organs of sense and the nervous 

 system. 



