CONTENTS xi 



CHAPTER XIV ENZYMES PAGES 

 Reaction velocities; enzymes as catalysts; general properties; 

 extracellular and intracellular enzymes; chemical nature; 

 nomenclature and classification; occurrence and preparation; 

 general and individual enzymes; nature of enzyme action; 

 accelerators and inhibitors; coenzymes and antienzymes; 

 zymogens; physiological uses; further studies needed; refer- 

 ences 181-201 



CHAPTER XV THE COLLOIDAL CONDITION 

 "Colloids" and " crystalloids "; the colloidal condition a dispersion 

 phenomenon; nomenclature and classification; conditions 

 necessary to the formation of sols; gel-formation; general 

 properties of colloidal solutions; suspensoids and emulsoids; 

 adsorption; catalysis affected by the colloidal condition; 

 industrial applications of colloidal phenomena; natural colloidal 

 phenomena; references 202-2^0 



CHAPTER XVI THE PHYSICAL CHEMISTRY OF PROTOPLASM 

 Heterogeneous structure of protoplasm; protoplasm a colloidal gel; 

 water; salts; osmotic pressure; surface boundary phenomena; 

 electrical phenomena; acidity and alkalinity; summary; vital 

 phenomena as chemical and physical changes; references 221-238 



CHAPTER XVII HORMONES, AUXIMONES, VITAMINES, AND TOXINS 

 External and internal stimulants; hormones; vitamines; auxi- 



mones, toxins 239-248 



CHAPTER XVIII ADAPTATIONS 



General discussion; adaptations, accommodations, and adjustments; 

 chromatic adaptations; morphological adaptations; accommoda- 

 tions; concluding statements 249-258 



INDEX . . . 259-268 



