Iviii 



commenced already in 1880, and his first memoir on the subject was 

 not published until the year 1885, during five years the great master 

 was engaged with his faithful assistants in elaborating and perfect- 

 ing a method for the prevention of rabies in human beings. The 

 results of these years of work may be briefly summarised in the 

 following concise words of Poux : — " The spinal marrows of rabid 

 rabbits when exposed to the action of the air, in a dry atmosphere, 

 become desiccated, and lose their activity. After fourteen days the 

 virus is attenuated to such an extent that it is harmless, even in the 

 largest doses. A dog receiving this fourteen-days-old marrow, then 

 on the following day thirteen-days' marrow, then that of twelve 

 days, and so on up to the fresh spinal cord itself does not take 

 rabies, but has become immune to it. Inoculated in the eye or in 

 the brain with the strongest virus it remains well. In fifteen days, 

 therefore, it is possible to confer immunity upon an animal from 

 rabies. Now, human beings bitten by mad dogs do not usually 

 develop rabies until a month, or even longer, after the bite. This 

 time of incubation can be utilised to render the person bitten re- 

 fractory." 



Still, however, the most difficult, the most perilous task remained 

 to be accomplished — the application of the knowledge and experience 

 thus acquired to the prevention of rabies in man. It was in July,. 

 1885, that this momentous step was taken, and in October of the 

 same year, Pasteur communicated that celebrated memoir to the 

 Academy of Sciences in which he described the results of what he 

 modestly designated a " tentative heureuse." A profound impression 

 was produced by this successful result, and wounded persons soon 

 streamed in from all parts, and during the following year as many 

 as 2,682 individuals were treated, each of whom on an average, 

 received between fifteen and twenty inoculations. Nearly 20,000 

 persons have now undergone Pasteur's anti-rabic treatment at the 

 Paris Institute, and the mortality has been less than 5 per 1,000. 



This magnificent triumph was not easily secured, and it was 

 amidst the most determined opposition at home and abroad that 

 Pasteur had to fight over two years for the public recognition of 

 this great discovery ; the effect of this strain told terribly upon his 

 health, and Pasteur was obliged to give up his life in the laboratory, 

 although he never ceased, down to the very last days of his life, to 

 take the keenest interest in all the investigations which were 

 being carried out in that great institute which bears his name, and 

 which is the public expression of gratitude for the magnificent 

 services to suffering humanity with which his name will for ever 

 be associated. 



It was in November, 1888, that the Institut Pasteur was opened 

 with a brilliant ceremonial, by the President of the Republic, and 



