PREFACE TO THE SECOND EDITION. 



IN preparing this second edition of u Pathogenic Bac- 

 teria ' ' I have endeavored to bring the work up to date 

 in all departments of the subject by introducing brief 

 mention of all recent work accomplished in bacteriology. 

 In order to aid the student whose particular interest 

 might make him desire to refer to the original papers, 

 I have thought well to depart from the plan of the orig- 

 inal work and give the references in the form of foot- 

 notes. 



Without departing too much from the primary descrip- 

 tive purpose of the book, I have made it a special point 

 to add considerably to the amount of technique it con- 

 tains, and so make it fulfill the double purpose of a sys- 

 tematic work upon bacteria and a laboratory guide. 



New chapters have been added dealing with the bac- 

 teriology of Whooping-cough, Mumps, Yellow Fever, 

 Hog-cholera, and Swine-plague ; describing the Bacillus 

 aerogenes capsulatus and the Proteus vulgaris ; and 

 describing the Methods of Determining the Value of 

 Antiseptics and Germicides, and of Determining the 

 Thermal Death-point. 



To a number of friendly readers whose suggestions 

 have been helpful in improving the work, I desire to 

 extend my sincere thanks. 



JOSEPH McFARLAND 



