PREFACE 



The administration of the Federal Pure Food and Drugs Act 

 and of the several State Pure Food and Drugs Laws has made the 

 introduction of bacteriological methods into food and drugs 

 laboratories a necessity. Because of the close relationship be- 

 tween the work of the bacteriologist and that of the micro-analyst, 

 it is advised that, wherever possible, these two laboratory branches 

 be combined in the most effectual cooperative manner. With 

 such cooperation in mind, a brief introduction to micro-analytical 

 methods is added. Fuller details on micro-technique will be 

 found in special works on the microscopy of fibers, foods, spices, 

 drugs, of water supplies, of sewage, etc. 



As is more fully set forth in the text, the bacteriological as 

 well as micro-analytical methods in our food and drugs labora- 

 tories are not yet fully worked out, and the present volume is 

 submitted hoping that it will be instrumental in bringing about 

 a unification of methods and that it will perhaps also serve as a 

 guide to the working out of newer and inadequately tested older 

 methods. 



The volume is primarily intended as a guide to students who 

 are interested in the bacteriological examination of foods and 

 drugs. Its use as a laboratory guide presupposes a thorough 

 knowledge of general bacteriology. 



Acknowledgments are made to the following authors for the 

 use of illustrations: E. R. Stitt (Bacteriology, Blood Work and 

 Animal Parasitology), R. L. Pitfield (Compend on Bacteriology), 

 W. J. MacNeal (Pathogenic Micro-organisms), C. E. Marshall 

 (Microbiology), John F. Anderson and Thomas B. McClintic 

 (Method of Standardizing Disinfectants), and G. W. Hunter (Es- 

 sentials of Biology). 



333721 



