PREFACE TO SECOND EDITION. 



A T the request of the publishers the author has again under>taken 



a revision of his Manual of Bacteriology, published in 1892: 



This is practically a third edition of that work, although the title 



was changed in 1896, and it now appears as a second edition of a 



TEXT-BOOK OF BACTERIOLOGY. 



Considerable additions have been made to the present edition, in- 

 cluding a section on " Protective Inoculations in Infectious Diseases," 

 and one on the " Bacteria of Plant Diseases." In order that the size 

 of the work might not be materially increased, descriptions of species 

 imperfectly described, or of minor importance, have been omitted. 

 In the Manual of Bacteriology an attempt was made to include all 

 species or distinct varieties which had been described by competent 

 bacteriologists up to that date, and to give a very full bibliography of 

 the subject. It was found to be impracticable to follow this plan in 

 bringing out a second edition as it would have called for two large 

 volumes instead of one, and the limited demand for such a work 

 would probably have made it a losing venture for the publishers. 

 In the TEXT-BOOK, therefore, the bibliography and the descriptions 

 of many non-pathogenic species were omitted. The Manual is now. 

 out of print, and those who have use for a comprehensive work, in 

 which an attempt has been made to include all species described up 

 to date of publication, are referred to Migula's " System der Bak- 

 terien " (Gustav Fischer, Jena, 1900). 

 WASHINGTON, May 27th, 1901. 



