Ill PASTEUR AND HYDROPHOBIA 135 



experimentally by repeatedly inoculating a dog with 

 the saliva of rabid dogs which proved fatal to other 

 individuals which were experimented upon at the 

 same time, whilst the particular dog in question 

 always proved refractory or non- liable to the disease. 

 No estimate has been at .present formed of the pro- 

 portion of dogs which are thus free from liability 

 to the disease, but it must be very small, perhaps not 

 1 per cent. On the other hand, it is undeniable that 

 there is a high probability that such immunity exists 

 among human beings, and it is possible that the 

 proportion of individuals liable to the infection as 

 compared with those "immune/' "refractory," or "non- 

 liable" is less amongst human beings than among 

 dogs. Such a constitutional immunity may, therefore, 

 possibly explain to a certain extent the fact that out 

 of 100 cases of dog -bite, the dog being supposed, 

 but not demonstrated, to be rabid, only 16 acquire 

 hydrophobia, 



The result of M. Pasteur's experimental study of 

 rabies and hydrophobia has been so far to place several 

 matters of practical importance, which were previously 

 liable to be dealt with by vague guesses and general 

 impression, in the position of facts capable of accurate 

 experimental determination ; and secondly, to intro- 

 duce a method of treating animals and men infected 

 with the poison of rabies in a way which, there is 

 strong evidence to show, will arrest or altogether pre- 

 vent the development of the disease. 



Owing to the eagerness of newspaper correspond- 

 ents, and the peculiar circumstances of the investiga- 



