CONTENTS ^ 



CHAPTER PAGE 



XVIII. Fermentation of Polysaccharides and Fats — The 



Gtjms — Hemicelluloses and Celluloses 220 



Distribution — Fermentation — Fermentation of Pecgin, the 

 process of retting — Fermentation of starch and iaulin — 

 Fermentation of fatty acids and glycerin. 



XIX. Decomposition of Organic Nitrogenus Compounds — 



Ripening of Cheese and op Meat 228 



Types of organisms — ^The anaerobic, putrefactive bac- 

 teria — Aerobic, proteolytic bacteria — Proteolytic 

 changes in foods — The ripening of cheese — Types of 

 cheeses — Ripening of meat. 



XX. Bacteria of the Soil — The Cycles of the Elements . . . 238 

 Importance of bacteria in the soil — Abundance and dis- 

 tribution of bacteria in the soil — Cycles of the elements — 

 The cycle of nitrogen in nature with special reference to 

 the soil — Outline — Proteolysis, ammonification or de- 

 aminization — Nitrification — ^Assimilation of nitrogen by 

 plants — Denitrification — Nitrogen fixation — The cycle 

 of carbon — Production of carbon dioxide in soil by mi- 

 croorganisms — The decomposition of insoluble carbohy- 

 drates in the carbonaceous matter in the soil — The 

 cycle of phosphorus — The cycle of sulphur — Organ- 

 isms oxidizing hydrogen sulphide and free sulphur— Or- 

 ganisms reducing sulphates to sulphides — The cycle of 

 iron. 



SECTION V 



MICROORGANISMS AND DISEASE 



XXI. Disease, Infection, and Resistance 273 



Disease— Contagious and noncontagious diseases — 

 Factors predisposing to disease — Heredity and dis- 

 ease — Immunity — Exhaustion theory of immunity — ■ 

 Noxious retention theory — Pythogenic theory of 

 disease — Ehrlich's Humoral Theory of Immunity — 

 Metschnikoff's Theory of Phagocytosis — Kinds of 

 immunity — Factors which determine immunity — 

 Antigens and their corresponding antibodies — Toxins 

 and antitoxins — Sources of toxins — Origin of anti- 

 toxin — Manufacture of diphtheria antitoxin — Prep- 

 aration and standardization of toxins — Injection 

 of the toxin — Standardization of antitoxin serum — 

 Preparation and utilization of other antitoxins — 

 Agglutinins and pricipitins — Colloidal solutions and 

 suspensions — ^Agglutination — Protein Precipitation 



