viii CONTENTS 



CHAP. PAGE 



V. THEORIES AS TO MODE OF ACTION OF CATALYSTS 



AND ENZYMES 126 



Summary regarding Theories of Catalytic Action and 



Correlation of these Theories 134 



Means other than Catalysis by which Chemical Reactions 



can be induced, or Reaction Velocity varied . . .135 



Bibliography 138 



VI. SECRETION AND GLANDULAR MECHANISMS . . 139 



Intrinsic Activity of Secreting Cells 143 



The Energy Changes involved in Secretion . . . . . 159 



The Extrinsic Mechanisms of Secretion 167 



Influence of the Nervous System upon Secretion . . . 169 

 The Chemical Mechanisms of Secretion Chemical Excitants 



or Hormones 183 



Bibliography . . . . . . . . . .194 



BY LEONARD HILL 



VII. THE ATMOSPHERE . 196 



VIII. THE EFFECT ON LIFE OF LESSENING THE BARO- 

 METRIC PRESSURE 210 



Mountain Sickness . . . . . . . .215 



Balloon Sickness 219 



The Results obtained by the Use of Pneumatic Chambers . 221 



The Effect of Increased Pulmonary Ventilation . . . 226 



The Metabolism in High Altitudes 229 



Changes in the Circulatory and Respiratory Mechanisms 



occurring in High Altitudes ...... 230 



The Blood-Corpuscles in High Altitudes .... 231 



Susceptibility to Mountain Sickness 232 



The Therapeutic Value of Mountain Air .... 232 



IX. THE INFLUENCE OF INCREASED ATMOSPHERIC 



PRESSURE 233 



The Metabolism in Compressed Air 237 



Effects on the Lungs 239 



The Immunity of the Swim-bladder to Oxygen-Poisoning . 241 



Effect on the Neuro-Muscular System 243 



Effect on the Central Nervous System 243 



Effect on the Blood Gases 244 



Effect on the Circulation . 245 



