yi PREFACE. 



mainder are drawn chiefly from th'e works enumerated at 

 the end of each section. These lists, however, represent but 

 a small part of the enormous mass of literature dealing with 

 Bacteria and their Products, which has accumulated durimg 

 the last decade. 



To Professor Loffler's admirable work, "Vorlesungen 

 iiber die geschichtliche Entwickelung der Lehre von den 

 Bacterien," and to Mr. Watson Cheyne's "Antiseptic 

 Surgery," I am specially indebted for much information and 

 guidance in my search for facts and papers dealing with the 

 earlier history of the subject. 



It may be said of the Appendix that it is given, not with 

 the object of supplying intending workers with every known 

 method of research, and with full descriptions of every 

 organism with which they may have to deal, but simply to 

 enable them to commence work, and to recognize the 

 commoner forms of Bacteria, of which about one hundred 

 and forty are here described. 



I take the opportunity of expressing my thanks to Dr. 

 Cartwright Wood, who, whilst revising the proof sheets, 

 has made several valuable suggestions ; to my former as- 

 sistant, Mr. Coghill, now of the Royal Veterinary College, 

 and to Mr. Andrew Pringle, both of whom have made for 

 me beautiful photo-micrographs, which, however, can be but 

 imperfectly reproduced by any photo-mechanical process 

 now available. 



G. S. W. 



