VI PREFACE. 



structions which would be given by a teacher when 

 watching a beginner making a simple bacteriological 

 examination for the first time. 



It cannot be too strongly urged that the practitioner 

 should make the examination for himself whenever it is 

 possible for him to do so. The report which is sent 

 from a public laboratory may often be of very consider- 

 able value, but it must be remembered that the bac- 

 teriologist can only supply facts, and the inferences 

 which may be drawn from those facts will largely 

 depend upon a knowledge of the patient's clinical 

 history and the method in which the material w r as 

 obtained. The bacteriologist is too often in the posi- 

 tion of a detective who has to unravel a mystery from 

 observations made by other people, and has no oppor- 

 tunity of making investigations for himself. A bacterio- 

 logical examination which is made by one person and 

 interpreted by another, or which is made on material 

 which has passed through more hands than one, loses 

 much of its value; and an investigation made on the 

 spot may be more valuable than one made by a bac- 

 teriologist of far greater experience at a distance. 



The methods which are described in this little book 

 are not in all cases the ideal ones, and in some cases 

 they are somewhat different from those which are 

 generally used, but they are simple and efficient. Of 

 course, the simple examinations which are described 

 here would frequently be supplemented by more com- 

 plicated cultural ones by a trained bacteriologist. 

 The methods described here have been taught in 

 the post-graduate classes which were initiated some 

 two years ago in the University of Birmingham ; 

 these have already been attended by about a hundred 

 practitioners, who have found these methods of great 

 assistance to them in their everyday practice. They 

 have been selected so as to provide examples of some 

 of the more important operations in constant use in 

 the bacteriological laboratory. The author takes this 

 opportunity of expressing his cordial thanks to Professor 

 Leith for his kind suggestions as to the general scope 

 of the book. 



