CONTENTS 



SECTION III 

 PHISIOLOGY OF MICROORGANISM 



CHAPTER PAGE 



IX. EFFECT OF PHYSICAL ENVIRONMENT UPON MICROORGAN- 



ISMS ............................................. 115 



Rates of growth and death Effect of light Effect of 

 heat The minimum temperature Optimum growth 

 temperature - - The maximum temperature Growth 

 temperature range Thermal death point Effect of 

 electricity Affect of X-rays and radium rays Effect of 

 pressure Effect of osmotic pressure Effect of desicca- 

 tion. 



X. PHYSICAL EFFECTS PRODUCED BY MICROORGANISMS ....... 127 



Light produced by microorganisms Production of heat 

 Changes in viscosity Effect on osmotic pressure. 



XI. EFFECT OF CHEMICAL ENVIRONMENT UPON MICROORGAN- 



ISMS ............................................. 131 



Effect of chemicals on direction of movement Effect of 

 chemicals on direction of growth Effect of chemicals 

 on rapidity of growth Effect of hydrogen ion concen- 

 tration on rapidity of growth Effect of oxygen upon 

 rapidity of growth Effect of kinds of nutrients present 

 Effect of concentration of nutrients Stimulating 

 effects of dilute poisons Effect of autogenic substan- 

 ces Effect of chemicals upon rate of death Charac- 

 teristics of an ideal disinfectant Effect of hydrogen 

 ion concentration upon death rates Alkalinity or alka- 

 lies Salts of the heavy metals The non-electrolytes 

 Oxidizing agents Essential oils Stimulation of disin- 

 fection Autogenic products Use in therapeutics. 



XII. CHEMICAL CHANGES PRODUCED BY MICROORGANISMS 



ENERGY RELATIONSHIPS ........................... 147 



Sources of Energy Sunlight as a source of energy to mi- 

 croorganisms Oxidation as a source of energy for micro- 

 organisms Methods of securing energy by oxidation 

 Cycles of the elements The nitrogen cycle The car- 

 bon cycle The sulphur cycle. 



XIII. MECHANISM OF CHEMICAL CHANGES PRODUCED BY MICRO- 



ORGANISMS ENZYMES AND FERMENTATION ............ 157 



Enzymes The hydrolytic enzymes or hydrolases The 

 splitting and oxidizing enzymes Fermentation The 

 origin of the products of fermentation. 



