148 Heredity and Social Progress 



We have retained the simplicity of the uni- 

 cellular organism in no place so plainly as in 

 our reasoning: here consciousness shows its 

 elementary and primitive character. No outer 

 organ has its simplicity; digestion, for ex- 

 ample, now demands a hundred independent 

 reactions. 



These three agents of acquired characters 

 imitation, fear, and reason are supple- 

 mented by one of a different origin. I have 

 said that the outer organs of expression are 

 more subject to change than are the inner 

 organs. The inner organs may therefore force 

 modifications upon the outer organs which 

 adapt them to conditions imposed by the rigid- 

 ity of the inner organs as well as to the condi- 

 tions set by the environment. The more rigid 

 alters the less rigid ; the environment and the 

 inner organs of expression being more rigid 

 than the outer organs, the latter are cut back 

 by the internally and externally excited emo- 

 tions, after which they grow again to meet 

 the new conditions. 



But this relative rigidity of the inner and 

 outer organs may be changed by bodily disci- 



