XXXll INTRODUCTION. 



bearing upon the subject, though Pasteur himself 

 kept clear for a long time of this special field of in- 

 quiry. He was not a physician, and he did not feel 

 called upon to trench upon the physician's domain. 

 And now I would beg of him to correct me if, at this 

 point of the Introduction, I should be betrayed into 

 any statement that is not strictly correct. 



In 1876 the eminent microscopist, Professor Cohn 

 of Breslau, was in London, and he then handed me 

 a number of his ' Beitrage,' containing a memoir 

 by Dr. Koch on Splenic Fever (Milzbrand, Charbon, 

 Malignant Pustule), which seemed to me to mark an 

 epoch in the history of this formidable disease. "With 

 admirable patience, skill, and penetration, Koch fol- 

 lowed up the life history of bacillus cuithracis, the con- 

 tagium of this fever. At the time here referred to he 

 was a young physician holding a small appointment 

 in the neighbourhood of Breslau, and it was easy to 

 predict, as I predicted at the time, that he would soon 

 find himself in a higher position. When I next heard 

 of him he was head of the Imperial Sanitary Institute 

 of Berlin. Koch's recent history is pretty well known 

 in England, while his appreciation by the German 

 Government is shown by the rewards and honours 

 lately conferred upon him. 



Koch was not the discoverer of the parasite of 

 splenic fever. Davaine and Eayer, in 1850, had ob- 

 served the little microscopic rods in the blood of 



