364 The Philippine Journal of Science 
sanitation and sanitary engineering and to various industries 
and technological pursuits. For the general scientific student 
and reader bacteriology presents certain aspects that tend to 
widen the outlook upon a variety of human interests. 
It need hardly be said that within the compass of this work 
an exhaustive treatment of all sides of bacteriology is impos- 
sible. The needs of the advanced worker can be met only—and 
that but in part—by such monumental special treatises as the 
Handbuch der Pathogenen Mikrotérganismen, edited by Kolle 
and Wassermann, and the Technische Mykologie, edited by La- 
far. A general introduction to the subject, however, with some 
regard for perspective and with emphasis on general rather 
than on special questions has seemed worth attempting. 
The reader who wishes to acquire greater familiarity with 
the subject will find some bibliographical references given as 
a sort of first aid to the investigator. These include references 
to some articles of classic or historic interest, to some giving 
valuable summaries or bibliographies of important subjects and 
to a few in fields where investigation is very active or opinions 
considerably at variance. No pretension to completeness is 
made. | 
The fundamental principles and methods of laboratory work 
are treated as fully as seems desirable in a book of this class. 
The tendency manifested in all the natural sciences towards the 
elaboration of special laboratory manuals and guides has much 
_ in its favor. A number of such guides for bacteriology are in 
existence, among which may be mentioned the excellent manuals 
of Frost, Gorham, Heinemann, Moore and Novy, to mention 
only American authors. In any case a proper familiarity with 
laboratory methods can be gained only with the assistance of 
a skilled laboratory instructor possessed of individuality and 
resource. 
FROM PREFACE TO THE SIXTH EDITION 
In this edition the chapter on The Pneumococcus has been 
entirely rewritten and that on The Meningococcus extensively 
revised. Several new sections have been added, including brief 
summaries of our present knowledge of infectious jaundice, rat- 
bite fever, and trench fever. A number of minor changes and 
corrections have also been made throughout the text. 
