PREFACE 



THE present volume is the outgrowth of a course of lectures 

 on Eugenics which has been given for several years in the Univer- 

 sity of California. Its aim is to present an account of the various 

 forces which are at present modifying the inherited qualities of 

 civilized mankind. In dealing with so extensive and complex 

 a subject I have doubtless committed a number of errors and have 

 probably not altogether escaped from being misled by statistical 

 fallacies into which I have so often accused others of having 

 fallen. The more extensively I have delved into the varied 

 literature on the biological evolution of man, the more I have 

 become impressed with the necessity of employing extreme cau- 

 tion in drawing conclusions. Few subjects, in fact, present so 

 many pitfalls for the unwary. It is with the conviction that it is 

 especially important in this field to be sure one is right before 

 going ahead that I have devoted so much effort to critical analysis 

 at the risk of becoming tedious to the general reader. 



I am indebted to my colleagues Professor F. B. Sumner and 

 Professor F. J. Teggart for reading my original manuscript and 

 for making a number of valuable suggestions. 



The preparation of the present work has involved the compila- 

 tion of an extensive bibliography which is to be published as an 

 additional volume so that the references may be rendered avail- 

 able for other investigators. 



S. J HOLMES 



Berkeley, Calif. 

 Jan. 1921. 



