THE VIRUS OF HYDROPHOBIA. 509 



paralytic rabies. This fact Pasteur explained by supposing 

 that the whole of the nervous system in such a case 

 becomes simultaneously affected. The virus seems to have 

 an elective affinity for the salivary glands, as well as for the 

 nervous system. Roux and Nocard found that the saliva 

 of the dog became virulent three days before the first 

 appearance of symptoms of the disease. 



The Virus of Hydrophobia. While a source of infection 

 undoubtedly occurs in all cases of hydrophobia, and can 

 usually be traced, all attempts to determine the actual 

 morbific cause have been unsatisfactory. In this connec- 

 tion various organisms have been described as being 

 associated with the disease. Undoubtedly several occur 

 not infrequently in the brains of animals and men dead of 

 rabies, and for two of these a causal connection has been 

 claimed. Thus Memmo has isolated an organism which 

 resembles a yeast, but which he places amongst the 

 blastomycetes, and with which he states he has produced 

 both types of rabies in rabbits and dogs. Bruschettini also, 

 by using media containing brain substance, has grown a 

 bacillus having some resemblances to the members of the 

 diphtheria group, and with which he claims to have produced 

 paralytic rabies in rabbits. In the case of the work of 

 neither of these observers has there been confirmation from 

 independent sources, and in neither case is there evidence 

 of the crucial test having been applied, namely, that of 

 immunising animals against the ordinary hydrophobic virus 

 by means of pure cultures of the alleged causal organism. 

 With regard to other possible causal agents, Grigorjew 

 thinks such may be found in a protozoon which he has 

 constantly observed after inoculation in the cornea. There 

 is no doubt that between rabies and the bacterial diseases 

 we have studied there are at every point analogies, the 

 most striking being the protective inoculation methods 

 which constitute the great work of Pasteur, and everything 

 points to a micro-organism being the cause. Judging from 

 our knowledge of similar diseases we would strongly suspect 

 that it is actually present in a living condition in the central 



