PREFACE. 



IN preparing this book the author has kept in mind 

 the needs of the student and practitioner of medicine, 

 for whom the importance of an acquaintance with prac- 

 tical bacteriology cannot be overestimated. 



It is to advances made through bacteriological re- 

 search that we are indebted for much of our knowledge 

 of the conditions underlying infection, and for the elu- 

 cidation of many hitherto obscure problems concerning 

 the etiology, the modes of transmission, and the means 

 of prevention of infectious maladies. 



Only within a comparatively short time have students 

 and physicians been enabled to obtain the systematic 

 instruction in this science that is of value in aiding 

 them in their efforts to check disease. The rapid in- 

 crease in the number who are availing themselves of 

 these opportunities speaks directly for the practical 

 value of the science. 



As the majority of those undertaking the study of 

 bacteriology do so with the view of utilizing it in 

 medical practice, and as many of these can devote to it 

 but a portion of their time, it is desirable that the 



