CONTENTS 



Chapter Page 

 I. An Introductory Orientation i 



II. The Hereditary Basis ii 



III. The Inheritance of Mental Defects and Disease 27 



IV. The Heritable Basis of Crime and Delinquency 73 



V. The Inheritance of Mental Ability 98 



VI. The Decline of the Birth Rate 118 



VII. The Causes of the Decline of the Birth Rate 143 



— JVIII. Natural Selection in Man 181^^/ 



IX. The Selective Influence of War 205 "7 



X. Sexual Selection and Assortative Mating {r'2'^) ' 



XI. Consanguineous Marriages and Miscegenation 238 



XII. The Possible Role of Alcohol and Disease in Causing 



Hereditary Defects 269 



XIII. The Alleged Influence of Order of Birth and Age of 



Parents upon Offspring 297 



^ XIV. The Racial Influence of Industrial Development 325 



XV. The Selective Function of Religion 355 



^XVI. Retrospect and Prospect 364 



V 



