CONTENTS. xi 



CHAPTER XXV. 



PAGES 



Infection and immunity The types of infection ; intimate 

 nature of infection Septicaemia, toxaemia, variations in in- 

 fectious processes Immunity, natural and acquired, active 

 and passive The hypotheses that have been advanced in 

 explanation of immunity Conclusions 559-615 



CHAPTER XXVI. 



Bacteriological study of water Methods employed Pre- 

 cautions to be observed Apparatus used, and methods 

 of using it Methods of investigating air and soil Bac 

 teriological study of milk Methods employed 616-648 



CHAPTER XXVII. 



Various experiments in sterilization by steam and by hot air . 649-653 



CHAPTER XXVIII. 



Methods of testing disinfectants and antiseptics Experiments 

 illustrating the precautions to be taken Experiments in 

 skin-disinfection 654-667 



APPENDIX. 

 Apparatus necessary in a beginner's bacteriological laboratory . 669-674 



