PREFACE 



THIS little volume embodies views recently presented 

 at the New York Academy of Medicine, in a lecture 

 before the Harvey Society for the Diffusion of Medical 

 Knowledge. Although the data on which this lecture 

 was based have been summarized in another publication, 

 I wish to present them more fully in the present volume 

 in order that some important details, not suited for pub- 

 lication in a medical journal, may be brought to the 

 notice of practitioners and investigators. The book 

 does not aim at a systematic discussion of the extended 

 and somewhat confused field of gastro-enteric infection, 

 either from a clinical or a bacteriological standpoint. 

 Neither does it make any claim to present fully the lit- 

 erature of this subject. 



I have laid considerable stress on methods developed 

 in my laboratory with a view to obtaining a better insight 

 into the bacterial conditions of the digestive tract than 

 has been hitherto possible. This I have done in the belief 

 that when these methods are utilized in practice they will 

 prove of real service in gaining a truer conception of the 

 nature of the bacterial processes that are operative in 

 disease. I am confident that the painstaking application 

 of these methods will furnish practitioners with new and 



535528 



