PREFACE TO THE FIFTH EDITION 



IN preparing this edition for the press I have made no altera- 

 tion in its plan, which seems to meet with general approval. 

 I have, however, added some sections which are somewhat 

 beyond its scope as originally conceived, and which will hardly 

 be required by the general practitioner, to whom the book 

 was, and is, primarily addressed. I have done this because I 

 find the book in common use as a general laboratory hand- 

 book amongst those who are called upon to deal with the 

 applications of bacteriology to disease. It appeared, there- 

 fore, necessary to go a little beyond the proper scope of the 

 book on certain points. 



I have inserted Mclntosh and Fildes' method for the Was- 

 sermann reaction, since a method with added complement is 

 generally (though I think erroneously) preferred, and I find 

 after a considerable amount of experience that this is a simple 

 and thoroughly reliable process. 



I owe a deep debt of gratitude to my good friends, the late 

 Captain Ridge and Captain Tanner, R.A.M.C., whose untimely 

 loss I so deeply deplore, the former for much useful advice, 

 the latter for the admirable illustrations he was so kind as to 

 draw for me. It is a pleasant duty to thank Professor Dreyer 

 and Major Perry for much information and advice concerning 

 typhoid fever, and Captain Inman for many valuable hints and 

 suggestions. 



I must also thank the Proprietors of The Practitioner for 

 permission to reproduce Fig. 32, Profs. Muir and Ritchie and 

 The Oxford Medical Publications for permission to use the 

 figures on Plate XL, and the Tintometer Company for the 

 illustration of Oliver's Hgemoglobinometer. 



November, 1916. 



