xiv CONTENTS 



CHAPTER XXVIII. 



WATER BACTERIOLOGY 



Classification of Waters 340 



Numbers of Bacteria in Waters 342 



Sedimentation 343 



Light 343 



Temperature 344 



Food 344 



Classes of Bacteria 345 



Soil Bacteria . . . , . .346 



Intestinal Bacteria 347 



Natural Purification of Water 347 



Artificial Purification of Water . . 348 



Chemical Methods 349 



Ice 350 



CHAPTER XXIX. 

 WATER AND DISEASE 



Disease First Definitely Proved as Due to Water 351 



Amount of Sickness Due to Water 352 



The Mills-Reincke Phenomenon 353 



Cholera 354 



Typhoid 354 



References . 359 



CHAPTER XXX. 



SEWAGE AND SEWAGE DISPOSAL 



Source, Composition and Quantity of Sewage 360 



Bacteria in Sewage 361 



Hydrolyzing Bacteria 362 



Oxidizing Bacteria 363 



Reducing Bacteria 363 



Pathogenic Bacteria 364 



Necessity of Sewage Disposal 366 



What Should Be Accomplished in Sewage Disposal? 366 



Methods of Dispoasal 366 



References 367 



CHAPTER XXXI. 

 MILK BACTERIOLOGY 



Milk as a Food 368 



Classes of Milk 371 



Bacteria in Milk 372 



Initial Contamination 372 



Growth of Bacteria in Milk 374 



Changes Produced in Milk by Bacteria ' . 375 



Abnormal Changes in Milk 376 



Classes of Bacteria 376 



Acid-forming Bacteria 376 



Peptonizing Bacteria 377 



Bacteria Producing Milk of Unusual Character 377 



Inert Organisms 377 



Pathogenic Bacteria 377 



