Foreword 



I WAS recently honored by an invitation to give the 

 Norman Wait Harris lectures at Northwestern Uni- 

 versity; the more so since as one of their side-door 

 neighbors I live close enough for my personal foibles 

 to be well known, thereby removing the chief source 

 of any possible glamour. In this book which grew out 

 of those lectures, as in the lecture series itself, I make 

 no effort to pose as the remote purveyor of a mys- 

 terious erudition; I could not in any case regard my- 

 self as more than the exponent of the glorified com- 

 mon sense which I more and more firmly believe all 

 science should be. 



Even more than most, this book is the outgrowth 

 of years of co-operative effort. Some of the basic 

 facts were collected with the aid of funds from the 

 Rockefeller Foundation given to aid biological re- 

 search at the University of Chicago. Other researches 

 were supported directly by that university and more 

 recently by a grant for the study of the effect of 

 hormones on behavior from the National Research 

 Council. 



13 



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