XX Preface 



oAve to them. I hope that my reference to their work, brief 

 though it is, will be recognized as indicative of the high im- 

 portance I attach to what they have done and are doing. 



But what about my indebtedness to professional associates 

 here in the home group of whose work no mention is made 

 in my text.'' How subtle and far-reaching and innumerable 

 are the influences which bear upon one from his daily co- 

 workers ! For example, by what unit of measurement could 

 be gauged the effects on my treatment of heredity, which have 

 come from my perpetual contact with the work of Dr. F. B. 

 Sumner and Mr. H. H. Collins.^ But these men would prob- 

 ably resent the ascription to them of responsibility for my 

 main conclusions in this field. Again, not many "environ- 

 mental factors" have been more determinative of my present 

 feelings (I hardly dare call them views) relative to various 

 problems in geo-physics, and relative to quantitative meth- 

 ods in natural science, than have Dr. G. F. McEwen and his 

 oceanographic work. Yet I hesitate even to mention this 

 fact lest some one be led thereby to hold Dr. McEwen ac- 

 countable for crudities, actual or implied, I may manifest 

 in these domains. 



Nor are my indebtednesses confined to the narrow circle 

 of my immediately professional and official co-workers. In- 

 deed I am keenly conscious of great debts bej'ond this circle. 

 These are so numerous and on the whole so general as to 

 make specification impossible, but I cannot pass by without 

 mentioning my debt to ray long-time and much-cherished 

 friend. Professor G. M. Stratton, for the commentaries on 

 the chapters on psychic integration made by him while this 

 portion of the book was in an advanced though still forma- 

 tive stage. 



For aid in structurel labor, as it may be called, my de- 

 pendence upon Mr. Frank E. A. Thone, my secretary and 

 scientific assistant, has been varied and intimate, and of a 

 quality for which money can only partly pay. 



