CONTENTS. IX 



PAET II. 



CHAP. PAGE 



I. The Evolution of Species — Natural Selection — Sexual Selection 



— The Action of the Environment independently of Selection 185 



II. Natural Selection — " Instinct and Eeason '" — Instinct a Perfect 



— Reason an Imperfect Guide 191 



III. Natural Selection (continued)— The Influence of " Reason" upon 



Natural Selection 201 



IV. Natural Selection (continued) — The Purely Accidental Causes of 



Death — Mai-Environments — The Necessarily-Fatal Environ- 

 ment — The Not-Necessarily-Fatal Environment — The Neces- 

 sary Mai-Environment 205 



V. Natural Selection (continued) — Deficiency of Food only an In- 

 direct Cause of Death in Civilized Communities . . . 210 



VI. Natural Selection (continued) — The Frequency of Natural Varia- 

 tions in Man — The Influence of Natural Selection on the 

 Mental Side of Man 214 



VII. Natural Selection (continued) — Its Influence on the Corporeal Side 

 of Man — Disease, a Necessary Evil — Active Operation of 

 Natural Selection in consequence of Instability of the Envi- 

 ronment—Perfect Adaptation Impossible — Illustrations . . 222 



VIII. Natural Selection (continued) — Adaptation to Micro-organisms — 

 The Instability of these latter interferes with the Process 

 of Adaptation 232 



IX. Natural Selection (continued) — The Necessarily-Fatal Environ- 

 ment 240 



X. Natural Selection (continued) — The Environment afforded by the 



Country 249* 



XI. Natural Selection (continued)— The Comparative Activity of the 



Process in Civilized and Primitive Man and in the Lower 

 Animals — The Relation between the Activity of the Process 

 and the Health of the Community 253 



XII. Natural Selection (continued) — Curtailment of the Number of 



Births in a Community hinders Evolution and favours Dis- 

 solution 261 



