Preface 



This manual is intended for use in those types of microbiological work 

 which involve the study of microbial cultures or of viruses, either for 

 identification or for learning the properties of the organisms investigated. 

 This book takes the place of the loose-leaf publication issued during the 

 period of 1923-1956 under the name of ''Manual of Methods for Pure 

 Culture Study of Bacteria." The present manual covers a wider scope but 

 still includes the subject of ''pure culture study, " the meaning of which is 

 discussed. 



The methods given here are not to be regarded as official. The com- 

 mittee has always taken the stand that official methods should not be 

 adopted in the case of research work, because it is continually necessary 

 to modify research methods in order to keep them up to date. The 

 standardization of methods tends to hinder the development of new 

 technics, while the chief function of this committee is to stimulate its 

 development. 



The methods in this manual, therefore, are merely claimed to be those 

 regarded as satisfactory by the committee at the time of publication. 

 Whenever practical, the methods have been tested by the committee in 

 comparison with other procedures. 



Of the chapters in this book, V, VIII, IX, X, and XI are almost 

 entirely new. The others are revisions, more or less complete, of leaflets 

 of the old manual. In the case of these revised chapters, the names of 

 the contributors at the chapter heads are the latest revisers, not the 

 original authors. In the case of the five entirely new chapters, however, 

 the actual authors are cited at the chapter heads. 



H. J. Conn 



M. J. Pelczar, Jr. 



Vll 



