PREFACE TO THE SECOND EDITION 



BACTERIOLOGY is essentially a practical study, and 

 even the elements of its technique can only be taught 

 by personal instruction in the laboratory. This is a 

 self-evident proposition that needs no emphasis, yet 

 I venture to believe that the former collection of tried 

 and proved methods has already been of some utility, 

 not only to the student in the absence of his teacher, 

 but also to isolated workers in laboratories far removed 

 from centres of instruction, reminding them of for- 

 gotten details in methods already acquired. If this 

 assumption is based on fact no further apology is 

 needed for the present revised edition in which the 

 changes are chiefly in the nature of additions ren- 

 dered necessary by the introduction of new methods 

 during recent years. 



I take this opportunity of expressing my deep 

 sense of obligation to my confrere in the Physiolog- 

 ical Department of our medical school Mr. J. H. 

 Ryffel, B. C., B. Sc. who has revised those pages 

 dealing with the analysis of the metabolic products 

 of bacterial life; to successive colleagues in the 

 Bacteriological Department of Guy's Hospital, for 

 their ready co-operation in working out or in testing 

 new methods; and finally to my Chief Laboratory 

 Assistant, Mr. J. C. Turner whose assistance and ex- 

 perience have been of the utmost value to me in the 

 preparation of this volume. I have also to thank 

 Mrs. Constant Ponder for many of the new line 

 drawings and for redrawing a number of the original 

 cuts. 



JOHN W. H. EYRE. 



GUY'S HOSPITAL, S. E. 



