CHAPTER XIII 

 THE EFFECT UPON HUMAN EVOLUTION 



The ubiquitous and deep-seated influence of the internal secre- 

 tions upon life and personality comprises but a fraction of what 

 is known, and only a hint of what is to become known. There is 

 an endocrine aspect to every human being and every human 

 activity, normal and abnormal, internal process and its external 

 expression, regulated by laws of which we are beginning to catch 

 a glimpse. Their control promises us now a dominion over the 

 most intimate and inaccessible recesses of our lives in a way 

 comparable only to the control we now exercise over the forces 

 and energies once revered as the instruments of the gods — light, 

 heat, magnetism, electricity. We have learned how to control 

 and change our environment. We are now learning, endocrine 

 research is now discovering, how to control and change ourselves. 



The story of the evolution of the two types of control has 

 many analogies. When man ceased looking upon his surround- 

 ings as inhabited by spirits of good and evil, as he conceived him- 

 self, and discovered that they were composed of things malleable 

 and analysable in his hands, he became their master. When now 

 he drops the old superstitions about himself as a spirit, an emul- 

 sion of a spirit of good and spirit of evil, and sees himself more 

 and more clearly as the most complex of chemical reactions, 

 regulated and determined as are the simple and complex chemical 

 reactions around him, he will begin to rule and modify himself 

 as he rules and modifies them. Whether or not he will ultimately 

 come to this final lucidity of thought and action, it behooves us 

 to consider some of the uses to which our present knowledge 

 might be put. 



Since every step of the daily routine or adventure, from waking 

 to sleeping, eating, drinking, marrying and giving in marriage, 

 working, idling, fighting, playing, feeling, enjoying, sorrowing, 

 every shade of emotion and nuance of mood, in short every 

 phase of happiness and unhappiness, are endocrine episodes in the 

 life history of the individual, the sphere of applications is as long 



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