SUMMARY 375 



While this list is by no means complete , we have 

 mentioned some organs and some chemical substances 

 the removal of which handicaps or destroys the individ- 

 ual. These organs and chemicals are purely material 

 things, purely mechanistic in their action. We thus 

 see that, at will, by depressing or removing this or that 

 organ, by administering this or that external agent, 

 muscular power and the production of heat are dimin- 

 ished or lost ; the action of the brain may be gradually 

 depressed until unconsciousness and death is reached. 

 It would seem that while a man-made machine is ap- 

 parently, it is not really, more dependent on chemistry 

 and physics than is that complex animal mechanism, 

 man. 



We have now followed, though imperfectly, the 

 career of the individual from his beginning in fertiliza- 

 tion, through the unconscious fetal days and the hazards 

 of birth to his conscious adult life. We have seen him 

 struggling to adapt himself to his environment in in- 

 fancy and in childhood and during adolescence. We 

 have seen his kinetic system driven by injury, by 

 emotion, by infection ; and have seen many diseases 

 result from his struggle with his internal and his ex- 

 ternal environment. We have seen him complete the 

 cycle of life through procreation. We have seen that 

 his death results from a vital break in his mechanism, 

 and that his ashes are returned to the elements whence 

 they came. From conception and birth to death, we 

 have seen that virtually every phenomenon of life is 

 mechanistic. We have studied the imperfect record 

 of the ascent of man's species from the time when, 

 having been driven by powerful enemies to the trees, 



