Microbic Diseases Individually Considered. 809 



Anti-rahic vaccinations. — It is possible to confer 

 immunity against rabies both upon man and sus- 

 ceptible animals. 



This immunity has been noted in certain cases of 

 natural rabies in which recovery took place. It was 

 especially well observed by Hoegyes in cases of ex- 

 perimental rabies followed by recovery. This author 

 records thirteen cases of recovery, six being of the 

 furious form, out of one hundred and fifty-nine in- 

 oculations to the dog. The immunity which followed 

 these recoveries was still in force after five years. 



Most generally, immunity is observed after inocu- 

 lations which are not followed by rabic symptoms ; 

 it may be obtained in various ways. Pasteur ob- 

 tained it in a dog by subcutaneous inoculation of 

 street virus in large amount ; this immunity, how- 

 ever, is not the rule, and in some cases rabies itself 

 appears. 



Hoegyes obtained immunity by injections of fixed 

 virus diluted in 0*7 per cent aqueous salt solution. 

 He made six inoculations in the dog with virus di- 

 luted to 1 to. 5,000, 1 to 2,000, 1 to 500, 1 to 100, and 

 1 to 10. The animal showed no sickness and con- 

 tracted a solid immunity against bites and diverse ex- 

 perimental inoculations. 



Immunity was obtained by Pasteur by inoculating 

 the dog with virus more or less attenuated in the 

 ape. 



The same author has conferred immunity on the 

 dog by subcutaneous inoculation of virus attenuated 

 by the method of desiccation above described. The 

 first inoculation is made with the cord of a rabbit 

 desiccated during fourteen days, that is, one which 



