A good many alterations will be discovered in this Second Edition; this is always the case with science. In matters of imagination, when the artist has finished his work, he can cast it on the world and follow his fancy in some other way. If science were only composed of truths, its conditions would almost be the same for its disciples; but the seeker after truth is not a creator like an artist, he explains and reflects upon a world of facts, variable at every hour, according as hypotheses are changed into certainties, or certainties of yesterday into doubtful cases of to-day. It is, then, an incessant work of reparation and alteration, in order to maintain even the most modest work in harmony with the daily progress of science; I have made this work as perfect as was in my power. I have taken great care with the list of authorities. I have also indicated by their titles all the articles from periodicals, reviews, or academic collections, to which I refer the reader. I am sure that those who know what an ungrateful task it is to search such badly catalogued libraries as most of ours are, will give me credit for this part of my work. We can only see the expression of science at a given moment in _Mémoires_. Books are, after all, merely a summary: they are behind-hand even on the day they are published. G. P. CONTENTS. PAGE EDITOR’S DEDICATION v EDITOR’S PREFACE vii AUTHOR’S DEDICATION ix AUTHOR’S PREFACE xi CONTENTS xiii INTRODUCTION 1 CHAPTER I. THE HUMAN KINGDOM 10 CHAPTER II. COMPARATIVE PSYCHOLOGY 24 CHAPTER III. THE ORDER OF BIMANA 38 CHAPTER IV. ANATOMICAL, PHYSIOLOGICAL, AND PATHOLOGICAL VARIETIES 43 CHAPTER V. INTELLECTUAL AND PHILOLOGICAL VARIETIES 62 CHAPTER VI. THE INFLUENCE OF CLIMATE 80 CHAPTER VII. THE INFLUENCE OF HYBRIDITY 95 CHAPTER VIII. SPECIES 108 CHAPTER IX. SYSTEM 134 INDEX OF SUBJECTS 153 INDEX OF AUTHORS 156 THE PLURALITY OF THE HUMAN RACE. INTRODUCTION.