CONTENTS ix 



XI. The Origin of Species by Natural 



Selection 137 



THE DIAGNOSTIC CHARACTERISTICS OF 



SPECIES AND THE ORIGIN OF SPECIES 



BY NATURAL SELECTION 142 



CHANCE AND EVOLUTION 144 



PROGRESSIVE EVOLUTION 148 



THE DOMINANCE OF THE WILD TYPE 



GENES lol 



XII. TJie N on -Inheritance of Acquired 



Characters 155 



XIII. Human Inheritance 179 



GENERAL STATEMENT 179 



INHERITANCE OF PHYSICAL DEFECTS 184 

 THE FOUR BLOOD GROUPS AND THEIR 



INHERITANCE 194 



INHERITANCE OF OTHER TRAITS 198 



THE INHERITANCE OF MENTAL TRAITS 200 



