BACTERIOLOG-Y. 



INTRODUCTION. 



" Omne vivum ex vivo " The overthrow of the doctrine of spontaneous 

 generation Earlier bacteriological studies The birth of modern 

 bacteriology. 



BACTERIOLOGY may be said to have had its begin- 

 ning with the observations of Leeuwenhoek in the 

 latter part of the seventeenth century. Though its 

 most rapid and important development has taken place 

 since about 1880, still, a review of the various evo- 

 lutionary phases through which it has passed in the 

 course of more than two hundred years reveals an 

 entertaining and instructive history. From the very 

 outset its history is inseparably connected with that 

 of medicine, and from the outcome of bacteriological 

 research preventive medicine, in its modern concep- 

 tion, received its primary impulse. Through a more 

 intimate acquaintance with the biological activities 

 of the unicellular vegetable micro-organisms modern 

 hygiene has attained almost the dignity of an exact 

 cc, and properly merits the importance and promi- 

 now generally accorded to it. From studies in 

 the domain of bacteriology our knowledge of the causa- 

 tion, course, and prevention of infectious diseases is 

 daily becoming more accurate, and it is needless to em- 

 phasize the relation of such knowledge to the manifold 

 problems that present themselves to the student of 

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