xii CONTENTS 



The Colloidal State 

 Colloidal Gold - 

 Emulsoids 



Swelling 



Surface Tension and Dispersion 

 Electrical Charge 

 Action of Electrolytes - 

 Mutual Precipitation 

 Staining and Electrical Adsorption 

 Rate of Reaction between Colloids 



CHAPTER II 



Chemical Composition of Organisms 

 The Polarimeter 

 Waste Products 

 Carbon Cycle 



Water Culture - 

 Action of Green Plant on Carbon Dioxide 



Chlorophyll 



Formation of Starch 

 The Nitrogen Cycle 



Bacteria 



Formation of Nitrates in the Soil 



Root Nodules - 

 Salts 



Sources of Energy 



Alimentary Canal of Frog and Rabbit 

 Enzymes and Digestion 



Rates of Reactions 



Hydrolysis by Enzymes 



Enzymes Act at their Surfaces 



Catalytic Action 

 Model 



Various Digestive Enzymes 

 Amylase - 

 Invertase - 

 Pepsin 

 Trypsin 

 Absorption - 



Histological Preparations 

 Voluntary and Involuntary Muscle 



Contractions of the Frog's Stomach 

 Secretion 



Pancreas 



Living Newt's Stomach 



Flow of Water - 



Electrical Change 

 Respiration - 



Tracheae of Insect 



Haemoglobin as Oxygen Carrier 

 Absorption Spectrum of Haemoglobin - 



Carriage of Carbon Dioxide 



Stimulation of Respiration by Carbon Dioxide 



