PEEFACE. 



This work is intended to be an introductory handbook 

 for the use of students, medical men, and others who 

 require a practical acquaintance with Bacteriology without 

 having at command the necessary time for a comprehen- 

 sive study of the mass of work which it comprises. 



Our purpose is therefore to give a concise account 

 of the principal facts which may fairly be considered to 

 have practical applications, and of the methods of ex- 

 amination by which they can be investigated. To persons 

 familiar with the science it is needless to say that it has 

 been impossible in the space at our disposal to give more 

 than a small fraction of the material which would be avail- 

 able for a treatise having the same object. We regret this 

 circumstance the less because persons engaged on other 

 subjects of study or of professional occupation, especially 

 those who have little or no previous knowledge of the 

 subject, could not assimilate anything like the whole mass 

 of conflicting observations which have been published, of 

 which, indeed, a large number must ultimately be super- 

 seded. We have endeavoured, however, to include those 

 results which may be considered as definitely established, 

 or appear most likely to be definitely developed in the near 

 future. 



