PREFACE TO FIRST EDITION 



The general awakening of the community to the 

 importance of the arts of sanitation — accelerated by the 

 rapid growth of cities and the new problems of urban 

 life — demands new and accurate methods for the study 

 of the microbic world. Bacteriology has long since 

 ceased to be a subject of interest and importance to 

 the medical profession merely, but has become intimately 

 connected with the work of the chemist, the biologist, 

 and the engineer. To the sanitary engineer and the 

 public hygienist a knowledge of bacteriology is indis- 

 pensable. 



In the swift development of this science during the 

 last ten years perhaps no branch of bacteriology has 

 made more notable progress than that which relates to 

 the sanitary examination of water. After a brief 

 period of extravagant anticipation, and an equally 

 unreasonable era of neglect and suspicion, the methods 

 of the practical water bacteriologist have gradually 

 made their way, until it is recognized that, on account 

 of their delicacy, their directness, and their certainty, 

 these methods now furnish the final criterion of the 

 sanitary condition of a potable water. 



