98 THE EVOLUTION OF MAN 



When the full import of these experiments is clearly recog- 

 nized, it must be admitted at once that the sex glands not only 

 control such secondary sexual characteristics as are of a physi- 

 cal nature, such as bodily proportions and the like, but also 

 those more subtile features, the reactions, responses, and in- 

 stincts, which are equally significant in defining a given sex. 

 These features collectively have their origin in the nervous 

 system and since they are now known, from the experiments of 

 Steinach, to depend for their development upon the sex glands, 

 it follows that the nervous system of an immature animal must 

 be looked upon as neither male nor female but indifferent and 

 yet capable of developing in either one or the other direction 

 in accordance with its organic environment. 



That the conclusions to be drawn from Steinach's experi- 

 ment apply with full force to human beings is now commonly 

 admitted. The striking influence of the sex glands on person- 

 ality as well as on the more physical aspects of the individual 

 is well known to every surgeon and is a cardinal point in his 

 practice. Yet the relation of this simple fact to human society 

 often goes unheeded. Few elements lie deeper in the nature 

 of man than sex. As the center around which the family is 

 built up, it initiates the first step in the structure of society. 

 From this soil have sprung the affections, chivalry, the poetry 

 of love, and all that vast array of literary and artistic ac- 

 complishment that has as its theme man and woman. And yet 

 when the physical background of this immense pageant is 

 sought for, it appears to depend upon the action of the inter- 

 stitial secretions of the sex glands on plastic nervous organs. 

 It is this plasticity that is both novel and important, for it may 

 have far-reaching consequences in the reconstruction of society. 

 Through it personality may be profoundly affected, abnormal 

 states may be reached and corrected, and fundamental re- 

 generations accomplished. As an avenue of entrance it leads 

 to a most important field for the psychiatrist and the social 



