| CHAPTER | | PAGE |
| I.— | From Known to Unknown | [1] |
| II.— | Review of the Position | [8] |
| III.— | The Problems Presented | [22] |
| IV.— | Initial Variations and Total Experience | [30] |
| V.— | Method of Proof | [36] |
| VI.— | Evidence from Arrangement of Hair | [39] |
| VII.— | The Evolution of Patterns of Hair | [50] |
| VIII.— | Can Muscular Action change the Direction of Hair in the Individual? | [64] |
| IX.— | Habits and Hair of Ungulates | [74] |
| X.— | Habits and Hair of Ungulates | [86] |
| XI.— | Habits and Hair of Carnivores | [92] |
| XII.— | Habits and Hair of Carnivores | [98] |
| XIII.— | Habits and Hair of Primates | [103] |
| XIV.— | Miscellaneous Examples | [115] |
| XV.— | Experimental | [124] |
| XVI.— | First Summary | [140] |
| XVII.— | Varieties of Epidermis | [145] |
| XVIII.— | Arrangement of the Papillary Ridges | [157] |
| XIX.— | Flexures of the Palm and Sole | [170] |
| XX.— | The Evolution of a Bursa | [178] |
| XXI.— | The Plantar Arch | [192] |
| XXII.— | Muscles | [200] |
| XXIII.— | Innervation of the Human Skin | [218] |
| XXIV.— | The Building of Reflex Arcs | [231] |
| Summary | [257] |
| Index | [259] |