On Rabies. 



73 



both died with usual symptoms of infection, after an incubation 

 period of 6 — 7 days. 



The dog, however, after recovering from the effects of the 

 anaesthetic, remained perfectly well and unaffected in any way, and 

 appears, as the first, to be completely refractory to infection by the 

 most active method of inoculation. 



From these two cases I should have concluded that the methods of 

 protective inoculation introduced by M. Pasteur were successful and 

 efficient in dogs, but the cases of the three unprotected animals 

 described (viz., D 8 and D 9 supra, and D 10), which are equally re- 

 fractory to infection, do nob support this conclusion as a result of the 

 limited number of my experiments upon this point. The virus of 

 rabbit rabies, almost invariably infective by intracranial inoculation to 

 animals of that species, would appear to be less certain in its action 

 upon dogs, and it is only by the results of a series of numerous com- 

 parative experiments that a final conclusion can be formed, whether 

 these methods have or have not any effect in increasing the constitu- 

 tional refractoriness of the dog to infection with rabies. I would add, 

 however, that it appears to me from the more numerous recorded expe- 

 riments of others upon dogs, viz., those of Professor Frisch, of Vienna, 

 and those of Professor Horsley at the " Brown Institution," exclusive 

 of those on an extended scale by M. Pasteur himself, in all of which 

 infection seems to have been invariably produced by intracranial in- 

 oculation, that the principle of protection is established, and that in 

 some cases at least, judged by the results of comparative experiments, 

 increased refractoriness to infection in the dog is produced by the 

 methods indicated, which is as much as could be expected or hoped 

 for, immunity, as above remarked, being always merely relative. 



With regard to the protective inoculation of man, the end and 

 object of M. Pasteur's work, this cannot be conclusively judged by 

 the result of experiments upon the lower animals of widely different 

 constitution; for in the rabbit and the dog its effect is very dissimilar; 

 all that this can do is to establish or disprove the principle of the 

 method. It is by the statistics of the treatment in man that it must 

 be judged. These will no doubt be examined exhaustively by the 

 Parliamentary Commission now sitting. 



Taking, however, the accounts last published (' Comptes Rendus,' 

 24th January, 1887) in which the number of patients treated is stated 

 at 2682, and the deaths amongst them from all causes 31, or only 

 1*15 per cent., it appears probable that the treatment has been suc- 

 cessful in at least some cases, since all published statistics, widely as 

 they vary, give a mortality from the bites of rabid dogs much in 

 excess of this. 



But beyond this, inasmuch as the last injection in each course is 

 made by Pasteur with virus dried for one day only and not materially 



