PREFACE TO SECOND EDITION. 
te the request of the publishers the author has again undertaken 
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). 
Wasnineton, May 27th, 1901. 
