CONTENTS XV 



CHAPTER II, — Inhibition of Growth 232 



Poisons, germicides, disinfectants, .antiseptics, preservatives. — Mod6 of action. — 

 Factors influencing disinfection. — Classification of disinfectants. 



DIVISION IV.— Mutual Influences 



Symbiosis. — Meta6iosis. — Antibiosis. . . . .... . . 241 



PART III.— APPLIED MICROBIOLOGY 

 DIVISION I. — Microbiology of Air (Buchanan) 



CHAPTER I. — The MicroGrganisms of the Air and Their Distribution. . . 247 



Microorganisms present in the air. — -Occurrence in the air. — How microorganisms 

 enter the air, — Conditions for subsidence of bacteria.- — -Determination of the numlijer 

 of bacteria in the air. — Number of bacteria in the air. — Species of organisms in the 

 air. 



CHAPTER II. — Microbial Air Influence in Fermentation, Diseases, etc. . . . 252 

 Air as a carrier of contagion. — Organisms of the air and fermentation. — Freeing air 

 from bacteria. 



DIVISION II. — Microbiology qf Water and Sewage 



CHAPTER I. — Microorgansism in Water (Harrison) . . . 254 



Classes of bacteria found in water. — Natural water bacteria, soil bacteria and surface 

 washings, intestinal bacteria usually of sewage origin. — The number of bacteria in 

 rain, snow, hail, etc.. and in water from wells, up-land, surface waters, rivers, and 

 lakes. — Causes affecting the increase and decrease of the number of bacteria in water, 

 — Temperature, light, food supply, oxidation, vegetation and protozoa, dilution, sedi- 

 mentation, other causes. — Interpretation of the bacteriological analysis of water, — 

 Quantitative standards, qualitative standards. — Sedimentation, filtration and purifi- 

 cation of water, — Sedimentation and filtration, coagulation basins and filtration, 

 porous filters, purification by ozone, purification by heat, purification by chemicals. — 

 Location and construction of wells. 



CHAPTER 11. — Microbiology of Sewage (Phelps) . 274 



Bacterial flora of sewage. — Types of sewage bacteria, — -Putrefactive and anaerobic 

 bacteria (the liquefaction of protein, the fermentation of cellulose, the saponification- 

 of fats, the fermentation of urea, the reduction of sulphates and nitrates) , oxidizing 

 bacteria (the production of nitrates and nitrites, other oxidizing reactions), patho- 

 genic bacteria (prevalence and longevity, life in septic tanks and filters). — The culti- 

 vation of sewage bacteria, — Filters, anaerobic tanks. — The destruction of sewage 

 bacteria, — By biological processes, by chemical processes. 



DIVISION III. — Microbiology of Soil (Lipman) 



CHAPTER I. — MicroSrganisms of the Soil as a Factor in Soil Fertility. . 289 



Introduction. — The soil as a ciilture medium. — Moisture relations, — The amount 

 and distribution of rain fall, range of soil moisture, effect of drouth and excessive 

 moisture. — Aeration, — Mechanical composition of soils, aerobic and anaerobic activi- 

 ties, rate of oxidation of carbon, hydrogen and nitrogen, the mineralization of organic 

 matter. — Temperature, — Influence of climate and season, early and late soils, pro- 

 duction and assimilation of plant food. — Reaction, — Range of soil acidity, causes of 

 soil acidity, effect of reaction on number and species. — Food supply, — Organic mat- 

 - ter, the mineral portion of the soil. — Biological factors, — Fungi, algae, protozoa. 



