CONCLUSION 343 



so individual, in the ceaseless activities of life, 

 that we are justified in looking at the mechanisms 

 themselves as highly experimental and adaptive. 

 Adequately to picture the play of stimuli and reac- 

 tions capable of arising between two such nervous 

 mechanisms would be a task defiant of human 

 powers ; how impossible, then, to draw, even in out- 

 line, the complexities that arise from that free inter- 

 course of human beings which characterizes human 

 life in modern communities? We are obliged to 

 satisfy our legitimate interest, tinged with curiosity, 

 by a concentrated effort of imagination, to arouse 

 and revive or rather reconstruct a mental picture of 

 the make-up of the nervous system and its ingoing 

 and outgoing paths, while simultaneously endeavor- 

 ing to think of the play of forces within these mani- 

 fold structures during some definite state of activity. 

 For some minds even this crude effort yields a degree 

 of satisfaction, if it does no more than emphasize 

 anew the impossibility of the stupendous task. 

 Our failure to compass this undertaking need not 

 blind us to the consequences that flow from the 

 admission of the incomparable plasticity and cease- 

 less activity of the superior automatic nervous 

 mechanism. If the behavior of one elaborate autom- 

 aton influences that of another, the total behavior 

 of an individual must be the sum of these interactions 

 of nervous protoplasm of different brains with each 

 other and with the outer world. According to this 

 view we take no account of what is called freedom of 



