CONTENTS XV11 



. DIVISION III. PHYSICAL INFLUENCES (Rahn) 



CHAPTER I. WATER AS A PHYSJCAL FACTOR 263 



Osmotic pressure. Plasmolysis (salt and sugar solutions, colloidal solutions). 

 Desiccation. 



CHAPTER II. INFLUENCE OF TEMPERATURE 269 



Optimum temperature. Minimum temperature. Maximum temperature. 

 Biological significance of the cardinal points of temperature. End-point of fer- 

 mentation. Freezing. Thermal death-point. Resistance of spores. 



CHAPTER III. INFLUENCE OF LIGHT AND OTHER RAYS 278 



Phototaxis. X-rays. Radium rays. 



CHAPTER IV. INFLUENCE OF ELECTRICITY 282 



CHAPTER V. INFLUENCE OF MECHANICAL AGENCIES 283 



Pressure. Gravity. Agitation. 



DIVISION IV. CHEMICAL INFLUENCES (Rahn) 



CHAPTER I. STIMULATION OF GROWTH . . . . 286 



Chemotropism and chemotaxis. 



CHAPTER II. INHIBITION OF GROWTH 288 



Poisons, germicides, disinfectants, antiseptics, preservatives. Mode of action. 

 Factors influencing disinfection. Classification of disinfectants. 



DIVISION V. MUTUAL INFLUENCES 



SYMBIOSIS. METABIOSIS. ANTIBIOSIS 297 



PART III. APPLIED MICROBIOLOGY 

 DIVISION I. MICROBIOLOGY OF AIR (Buchanan) 



CHAPTER I. THE MICROORGANISMS OF THE AIR AND THEIR DISTRIBUTION. ... 303 

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

 enter the air. Conditions for subsidence of bacteria. Determination of the number 

 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. . . . 308 

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

 from bacteria. 



DIVISION II. MICROBIOLOGY OF WATER AND SEWAGE 



CHAPTER I. MICROORGANISMS IN WATER (Harrison) 310 



Classes of bacteria found in water, Natural water bacteria, soil bacteria from 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, coagulating basins and filtration, 

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

 Location and construction of wells. 



