LEAFLET I. INTRODUCTORY 

 PURPOSE OF THE MANUAL 



This Manual is intended for use in that type of bacteriological 

 work known as "pure culture study of bacteria", the meaning of 

 which is discussed below. 



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

 committee 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 develop- 

 ment of new technic, while the chief function of this committee is to 

 stimulate its development. This contention of the committee seems 

 now to be officially recognized by the Society of American Bacteri- 

 ologists, and this organization has of recent years left the establish- 

 ment of official methods to other bodies having closer connection 

 with regulatory work. At the request of the Society this Manual 

 now bears upon its title page the statement: ''The methods given have 

 not been Jonnally approved by the Society, and are in no sense official 



or STANDARD." 



The methods in this Manual, therefore, are merely claimed to be 

 the best that have come to the attention of the committee at the time 

 of publication. Whenever practical, the methods have been tested 

 by the committee in comparison with other procedures; when this has 

 not been done, methods are given with a statement to indicate that 

 they have not been critically tested. 



Meaning of Pure Culture Study 



There has sometimes been misunderstanding as to the sense in 

 which the Committee uses the expression "pure culture study of 

 bacteria". It is occasionally thought that such an expression would 

 cover nearly the whole field of bacteriological technic. On the other 

 hand, the definition of pure culture study of bacteria which has been 

 drawn up by the Committee on Bacteriological Technic is: the study 

 of bacterial cultures with the object of learning their characteristics 

 and behavior or determining their identity, or both. Such a study 

 may be regarded as including: isolation methods; methods for the 

 cultivation and the storage of various kinds of bacteria; the micro- 

 scopic study of pure cultures either stained or unstained; determina- 

 tion of cultural characteristics of an organism; a study of its physio- 

 logical characteristics; the chemical methods necessary in making the 

 last-mentioned study; the determination of pathogenicity and study 



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