86 SUPER-ORGANIC EVOLUTION 



life of plants and rudimentary animals, the progress 

 of life in the upper species consists essentially in a 

 continual adaptation between the organic processes 

 and those which enclose the organism. We have 

 seen that with complexity of their organisation 

 there is also an increase in the number, the 

 extension, the specialisation, and the complexity 

 of the adjustment of the internal to the external 

 relations. And, following this increase, we have 

 passed by gradual transition from the phenomena 

 of corporal to those of intellectual life." l 



With regard to this differentiation between 

 physical and psychic life, we particularly call the 

 reader's attention in order to facilitate his inter- 

 pretation of the law of evolution in its relation to 

 sociology ; since, although the spirit which under- 

 lies that law is the same in both cases, not so is 

 the letter, which is liable to cause confusion. 



"With the lower animals, each part of the 

 organism, if produced by and for itself, as well as 

 all the vital functions, respond in and by such parts 

 to external stimulus ; the psychic changes are 

 almost to the same extent as the physical both 

 simultaneous and successive. As the nervous 

 system appears, these psychic changes are visibly 

 co-ordinated, and a connection between their several 

 most perfect series is established. And in accord- 



1 H. Spencer, Principes de Psychologie, p. 298. 



