CONTENTS. XI 



PAGES 



hypotheses that have heen advanced in explanation of im- 

 munity — Conolasions . . 534-578 



CHAPTEE XXVII. 



Bacteriological study of water — Methods employed — Pre- 

 cautions to he observed — Apparatus used, and methods of 

 using them — Methods of investigating air and soil .... 579-610 



CHAPTER XXVIII. 



Methods of testing disinfectants and antiseptics — Experiments 

 Illustrating the precautions to be taken — Experiments in 

 skin-disinfection ... . 611-624 



APPENDIX. 



Apparatus necessary in a beginner's bacteriological laboratory 625-630 



