viii CONTENTS 



CHAPTER IV. 

 ACTION OF EXTERNAL INFLUENCES ON BACTERIA 



aECTION PAGE 



1. iNTLnENCE OF TEMPERATURE - 53 



2. „ Eleotricitt and Magnetism - 56 



3. „ Light 58 



4. „ Moisture 60 



5. „ Mechanical Agitatiox 61 



6. „ Gravity 62 



CHAPTER V. 



1. Motility in Response to External Stimuli 63 



2. Respiration of Bacteria 65 



3. The Food of Bacteria 65 



4. Chief Conditions Regulating Growth 69 



5. Physiological Classification 72 



CHAPTER YI. 

 DISTRIBUTION OF BACTERIA 



1. Bacteria is the Air 75 



Conditions determining bacterial contamination of air. 



2. Bacteria in Water 78 



3. Bacteria in the Soil - 82 



CHAPTER VII. 



STERILISATION 84 



Sterilisation of air — disinfectants — intermittent sterilisation — 

 sterilisation by moist and by dry air — autoclave— sterilisation by 

 light — sterilisation by aid of various chemical substances. 



