iv PREFACE 



who wishes to give attention to the comparative bacteriology of man 

 and the domestic animals. It may also find a place in the curriculum 

 of agricultural colleges where bacteriology is becoming more and 

 more taken up, and where it is also especially studied with reference 

 to veterinary science and to certain fermentative processes in the 

 soil, and in milk and milk products, as butter, cheese, etc. Micro- 

 organisms in relation to such processes have, therefore, been fully 

 considered. 



A somewhat novel feature for a book of this character has been 

 introduced, namely, the addition after each subject or chapter of 

 "Questions." A student may read a chapter once or even several 

 times, and he may think that he has fully mastered and well remembers 

 the subject. Yet when it comes to exercises in recitation in the class 

 room or to a written examination he may fail. The author, therefore, 

 believes that it will be of great advantage to the student to have after 

 each chapter a number of questions covering the subject treated, 

 and enabling him to put his knowledge to a test to find out whether 

 or not he has mastered the task of committing to memory the main 

 facts given. Such questions in a voluminous text-book or work of 

 reference would, of course, be unnecessary, but they will serve a useful 

 purpose in an elementary book for the beginner, whether he be 

 student or practitioner. 



The author has freely consulted the following works: Kolle and 

 Wassermann, Handbuch der Pathogenen Microorganismen; Kitt, 

 Eakterienkunde und Pathologische Mikroscopie fur Thierdrzte; Fliigge, 

 Die Mikroorganismen; Nocard and Leclainche, Les Maladies Micro- 

 biennes des Animaux; Moore, The Pathology and Differential Diag- 

 nosis of Infectious Diseases of Animals; Hutyra and Marek, Specielle 

 Pathologic und Therapie der Hausthiere; Laveran, Trypanosomes 

 and Trypanosomiases; Doflein, Die Protozoen als Parasiten und 

 Krankheitserreger; Calkins, Protozoology; Lafar, Technische Myko- 

 logie; Kraus and Levaditi, Handbuch der Technik und Methodik der 

 Immunitdtsforschung; the publications of the Bureau of Animal 

 Industry, United States Department of Agriculture, and those of the 

 Bureau of Science, Manila, P. I. 



M. H. 



CHICAGO, 1910. 



