xii INTRODUCTION 



on which I .saw the great master was in 1891 or 1892, when he 

 demonstrated at the Institute to a group of us the technique 

 of the procedure, and then superintended the inoculations of 

 the day. A large number of persons are treated in the course 

 of the year ; a good many, of course, have not been bitten by 

 mad dogs ; but a very careful classification is made : 



(a) Includes persons bitten by dogs proved experimentally 

 to have been mad. 



(b) Persons bitten by dogs declared to be mad by competent 

 veterinary surgeons. 



(c) All other cases. 



The mortality even in Class A is very slight, though many 

 patients are not brought until late. Incidentally it may be 

 remarked the lesson of this country in its treatment of hy- 

 drophobia is one of the most important ever presented in 



^connection with an infectious disease. There are no Pasteur 

 Institutes; there are no cases. Why? The simple muzzling 

 order has prevented the transmission of the disease from dog to 

 dog, and once exterminated in the dog, the possibility of the 

 infection in man had gone. In 1888 the crowning work of 

 Pasteur's life was the establishment of an Institute to serve as 

 a centre of study on contagious disease, and a dispensary for 

 the treatment of hydrophobia, which is to-day the most 

 important single centre of research in the world. The closing 

 years of his life were full of interest in the work of his 

 colleagues and assistants, and he had the great satisfaction of 

 participating, with his assistant Roux, in another great victory 

 over the dread scourge, diphtheria. Before his death in 1895 

 he had seen his work prosper in a way never before granted to 

 any great discoverer. To no one man has it ever been given to 

 accomplish work of such great importance for the well-being of 

 humanity. As Paul Bert expressed it in the report to the 

 French Government, Pasteur's work constitutes three great 

 discoveries, which may be thus formulated. 1. Each ferment- 



** ation is produced by the development of a special microbe. 



2. Each infectious disease is produced by the development 

 within the organism of a special microbe. 



