Vlll PREFACE. 



the careful clinical worker, to whom it is hoped this 

 little book may also prove useful. 



I take this opportunity of expressing my best 

 tkanks to Professor Virchow, who materially fur- 

 thered my work in the Pathological Institute of 

 Berlin by kind advice and generous assistance. 



I am most grateful to Dr. Babes, of Budapest* 

 for his ever-ready co-operation ; and to Professor 

 Johne, of Dresden, who also placed his laboratory 

 at my disposal, and to whom I am particularly 

 indebted for much of the material from which 

 the microscopical preparations were made. 



I would also wish gratefully to acknowledge the 

 great interest and courteous assistance shown me 

 on the part of Dr. Hauser, of Erlangen ; Professor 

 Pettenkofer, Professor Bollinger, and Dr. Biichner, 

 of Munich ; and the officials of the new Hygienic 

 Laboratory in Berlin. 



The original drawings from which the coloured 

 plates of test-tube- and potato-cultivations are 

 reproduced were made by my wife from cultiva- 

 tions prepared especially for the purpose, and 

 selected as typical. The coloured plates of the 

 microscopic appearances are reproductions of my 

 own drawings, from specimens I had recently 

 prepared. The drawings were made from parts 

 selected as most characteristic from a great number 



