PREFACE TO THE NINTH EDITION 



Tras ninth edition of the "Pathogenic Bacteria and Protozoa," has 

 been prepared under conditions as unfavorable for literary study 

 and compilation as can easily be conceived. The countries of 

 Europe were engaged in a terrible war into which the United 

 States had been drawn as a participant and every resource of 

 our country was requisitioned in order that tyranny might be 

 overcome and "democracy made safe for the world." 



The scholastic quiet of the author's university was invaded by 

 the call of the bugle, the voice of command and the tramp of march- 

 ing feet as the students were called from class-rooms and laboratories 

 to engage in military training. 



The author himself was called to serve in the army, and the actual 

 work of revision was accomplished "in the field." The "copy" 

 was prepared from memorandum notes, during long evening hours, 

 at the Base Hospital at Camp Beauregard, Alexandria, La.; the 

 "galley sheets" were read and corrected at the U. S. A. General 

 Hospital at Lakewood, N. J., and the finished pages were read at 

 the U. S. A. General Hospital No. 14 at Fort Oglethorpe, Ga. 

 and the U. S. A. General Hospital No. 19 at Azalea, N. C. 



Amid these distracting surroundings, away from books and jour- 

 nals, the old fabric was unravelled and rewoven to an extent that 

 necessitated the resetting of the type of the entire volume. It is, 

 however, hoped that old errors have been corrected, new ones 

 avoided, and enough new matter introduced to bring the whole 

 work up to date and greatly increase its practical value. 



It is with deep regret that we find, upon looking over the biblio- 

 graphic index, that more than two hundred and fifty of our friends 

 in science, whose work has been mentioned in the text, have become 

 our enemies in politics. That such a circumstance should arise is 

 deplorable; that it shall persist is inconceivable. 



It has always been the author's proud contention that men of 

 science formed a kind of international brotherhood, distinguished by 

 an unwearied ambition to free human existence of unnecessary 

 suffering and untimely death and to provide it with means of pro- 

 moting happiness and increasing longevity. With his vision 

 focused upon the work of the physician and sanitarian intent upon 



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