PREFACE TO SECOND EDITION 
In preparing the second edition I have availed myself 
of the opportunity to correct whatever errors were made 
previously, and to follow the various suggestions kindly 
made by the author’s friends, reviewers and others. 
The fundamental principles and the general plan of 
the book have been found by the teachers and the pupils 
alike to be quite satisfactory, especially the general sum¬ 
mary at the end of each chapter, and for this reason, 
the new edition contains .additions rather than altera¬ 
tions. 
The new subject matter now includes: 
1. Additional information about the constancy and 
the mutation of bacteria. 
2. Discussion of the D’Herelle’s phenomenon—one 
of the most important contributions since the days of 
Ehrlich and Bordet. 
3'. Description of some of the newer technical pro¬ 
cedures, such as Paltouf’s Modification of the Gram’s 
method of staining, Pappenheim’s method, and some cul¬ 
ture media. 
4. Thorough description of the rationale and the 
underlying principles of the Wassermann test. 
5. Description of the newer precipitation and floc¬ 
culation tests for the diagnosis of syphilis—Meinicke, 
Sachs-Georgi, Kahn and Dold tests. 
6. Discussion of the new-colorimetric—method of ti¬ 
trating culture media. 
7. Detailed description of taking blood cultures with 
the Keidel blood culture medium tubes. 
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