PREFACE TO SECOND EDITION 



The influence of applied bacteriology is extending 

 rapidly, and while formerly the science of micro- 

 organisms was chiefly confined to the medical field, it 

 has become of vast industrial importance. The gigan- 

 tic interests of fermentation industries, of the dairy, of 

 agriculture, of municipal sanitation, and of water puri- 

 fication are largely controlled by bacteriologists. A 

 knowledge of the principles of bacteriology is becoming 

 more and more desirable to the student of general 

 science, and teachers of domestic science in some 

 institutions are required to take an elementary course. 



The second edition of this laboratory guide has been 

 revised and enlarged with the view of meeting modern 

 requirements. The first edition was devoted chiefly to 

 medical bacteriology. This has been partly rewritten, 

 and in addition courses in general bacteriology, in the 

 bacteriology of water, in the bacteriology of milk, in 

 soil bacteriology, and a course on molds, yeasts, and 

 acetic-acid bacteria have been outlined. This change of 

 plan necessitated an entirely new arrangement of the 

 material. The preparation of culture media, of stains, 

 etc., has been incorporated in a separate part, and 

 reference to this part is made at the beginning of each 

 special part. The course in the bacteriology of water 

 is calculated to be combined with the physical, chemical, 

 and microscopic examination, the student being thus 

 prepared for sanitary water analysis. Similarly, the 

 course on the bacteriology of milk is to be given in 



