viii CONTENTS. 



CHAPTER VI. 



PAOK 



QUALITATIVE BACTERIOLOGICAL ANALYSIS . . . 41 



MICRO-ORGANISMS WHICH ARE FOUND IN PURE WATERS . 42 



CHAPTER VII. 

 NITRIFYING AND DENITRIFYING MICRO-ORGANISMS , .81 



CHAPTER VIII. 



MICRO-ORGANISMS WHICH ARE FOUND IN SEWAGE AND POLLUTED 



WATERS 88 



CHARACTERISTICS OF THE BACILLUS COLI COMMUNIS GROUP . 88 



METHODS EMPLOYED FOR THE ISOLATION OF THE B. COLI FROM 



WATER SUPPLIES .... . . . -98 



THE VALUE OF THE B. COLI COMMUNIS AS A SIGN OF SEWAGE 



CONTAMINATION OF A WATER SUPPLY .... 103 



CHAPTER IX. 



THE BACILLUS ENTERITIDIS SPOROGENES . . . . . ltT8 

 VALUE OF BACILLUS ENTERITIDIS SPOROGENES AS A SIGN OF 



SEWAGE CONTAMINATION . ... .112 



CHAPTER X. 



SPECIES OF STREPTOCOCCI AND STAPHYLOCOCCI. . . .115 

 VALUE OF STREPTOCOCCI AND STAPHYLOCOCCI AS A SIGN OF 



SEWAGE CONTAMINATION . . . . . . 124 



CHAPTER XI. 



THE PROTEUS GROUP . . . . . . . .125 



MICRO-ORGANISMS SUGGESTIVE OF SEWAGE CONTAMINATION 127 ' 



