12 PREFACE. 



The aim has been to describe only such bacteria as 

 can be proven pathogenic by the lesions or toxins 

 which they engender, and, while considering them, to 

 mention as fully as is necessary the species with which 

 they may be confounded. 



The book, of course, will find its proper sphere of 

 usefulness in the hands of medical students ; its pages, 

 however, will be found to contain much that will be 

 of interest and profit to those practitioners of medicine 

 who graduated before modern science had thrown its 

 light upon the etiology of disease. 



In writing this work the popular text-books have 

 been drawn upon. Hiippe, Fliigge, Sternberg, Frankel, 

 Giinther, Thoinot and Masselin, and others have been 

 freely consulted. 



The illustrations are mainly reproductions of the best 

 the world affords, and, being taken from the great stand- 

 ards, are surely superior to anything new covering the 

 same ground. Credit has carefully been given for each 



illustration. 



J. McF. 

 PHILADELPHIA, Feb. i, 1896. 



