PREFACE TO THE FIFTH EDITION 



THE present or Fifth Edition of the TEXTBOOK OF BACTERIOLOGY 

 represents an almost complete rewriting of the book. The four 

 preceding editions were in each case altered and brought up to 

 date from time to time, but in all of them the original plan of presen- 

 tation, conceived at the first writing, was preserved. In the present 

 edition many and important additions of material and changes in 

 manner of presentation have been made. 



Bacteriology and the reasoning based on bacteriological and im- 

 munological discoveries have become more and more closely interwoven 

 with the clinical and public health aspects of infectious diseases. 

 Indeed, if this had not been sufficiently apparent before 1914, the 

 experiences of the late war have demonstrated, conclusively, how im- 

 possible it is to organize either hospitals for infectious diseases or 

 organizations for the control of epidemics without the intimate 

 participation of men trained in bacteriology. It seems to us, also, 

 to have become apparent that the bacteriologist who takes an active 

 part in the work of a hospital or in directing sanitary undertakings, 

 must have a very thorough understanding of the clinical and public 

 health aspects of the problem as a whole. 



The conception upon which the preparation of the new edition of 

 the book has been based, therefore, is the belief that no thorough 

 understanding of the clinical problems of infectious disease or of 

 larger public health measures can be attained without thorough 

 familiarity with the bacteriological and immunological facts upon 

 which clinical and sanitary reasoning must be based. The book 

 represents, therefore, in a brief way, an attempt to correlate a labora- 

 tory knowledge with the branches of medicine and prophylaxis to 

 which it is most directly applicable. 



We have felt that a Textbook of Bacteriology, primarily aimed at 

 the needs of medical students and physicians, may be regarded 

 as neglecting a great opportunity or, perhaps, even an obligation, if 

 it omits emphasis upon prevention. In order to accomplish this purpose 

 it has been necessary to add brief clinical data in the case of each 



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