CONTENTS. 



Page. 

 Introduction 149 



Chapter I. 

 Review of the Literature 151 



Chapter II. 

 Material. General arrangement of the experiments . 161 



Chapter III. 

 Experiments in air 168 



Chapter IV. 

 Effect of the complète withdrawal of free oxygen 



on the perception 186 



Chapter V. 

 Efïect of the complète withdrawal of free oxygen 



on the reaction 197 



Chapter VI. 

 EfFect of an atmosphère with low oxygen-content . 204 



Chapter VII. 



Discussion of results 207 



Summary 211 



Bibliography 213 



