PREFACE TO THE EIGHTH EDITION 



It is a difficult thing to write a preface for an Eighth Edition. 

 No part of the work was found to be so embarrassing or was sub- 

 jected to greater procrastination. 



What can be said that has not been said seven times already? 

 Probably very little about the book; certainly very much about the 

 feelings of the author. 



He desires to express to those who have already made acquaintance 

 with the book, and may with friendly feehngs look into its new 

 edition, his sincere satisfaction and appreciation of the hearty 

 receptions that have been accorded his previous attempts. He also 

 desires to thank his reviewers for some helpful criticisms. 



So numerous are the additions, subtractions and alterations 

 to which the seventh edition was submitted in the preparation of 

 this Eighth Edition, that it might almost be said that the text had 

 been rewritten. Indeed they were such that the type of the entire 

 book has been reset. It now appear with slightly larger pages; 

 in two sizes of type, and gives a general effect of contraction, though 

 there is really an expansion of matter that would have covered more 

 than fifty of the old-size pages. 



The "Pathogenic Bacteria and Protozoa" is a medical work. 

 It is hoped that it shall be found helpful to medical workers — 

 students and practitioners of every class. 



Philadelphia, Pa. The Author. 



November, 1915. 



