BACTERIOLOGY IN MEDICINE AND SURGERY. 
INTRODUCTION. 
ALTHOUGH most of the more important discoveries 
in bacteriology which place it on the footing of a 
science are of comparatively recent date, the founda- 
tion of the study of vegetable and other micro-organisms 
was laid over two centuries ago. From the earliest 
times its history has been intimately associated with 
that of medicine. Indeed, it is only through the inves- 
tigations into the life-history of micro-organisms in their 
relation to disease that our present knowledge of the 
etiology, course, and prevention of the infectious diseases 
has been acquired ; and it is only by the practical ap- 
plication of the principles and methods of bacteriology 
that many diseases can be positively diagnosed or the 
problems which present themselves to the sanitarian be 
certainly solved. The prominent position which bac- 
teriology already holds toward medicine is, moreover, 
daily increasing in importance. Original discoveries are 
constantly adding to the list of known germ diseases, 
and the outlook is favorable for eventually obtaining 
through serums or through the toxic substances of the 
micro-organisms themselves means for immunizing 
against, if not curing, many of the specific infections. 
Even at present bacterial products and protective 
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