IMMUNITY. 203 



Inoculation Against Rabies or Hydrophobia.* The 



immunity produced in this case probably depends upon prin- 

 ciples similar to those underlying the examples related on the 

 preceding pages. But this question cannot be regarded as 

 settled until the organism of rabies has been isolated and cul- 

 tivated. Attempts to discover this organism have, as yet, been 

 futile, though certain minute bodies, bodies of Negri, have been 

 observed within ganglion-cells of the central nervous system 

 from cases of rabies, and it has been claimed that they are pro- 

 tozoa and the cause of the disease. Whether this is true or not, 

 Negri bodies make a most valuable means of rapid diagnosis. 



Frothinghamf regards the presence of the Negri bodies as 

 sufficient for diagnostic purposes without animal inoculation. 

 If these are not found in smear preparations from Ammon's 

 horn, they must be further sought in sections from this region 

 or in the cerebellum or in the Gasserian ganglion. If all these 

 tests are negative, and there are no lesions in the Gasserian 

 ganglion, then animal inoculation may be resorted to merely 

 to allay uneasines of the patient. 



DavisJ calls attention to the fact that the Negri bodies are 

 sometimes absent in undoubted cases of hydrophobia. Such 

 cases are very few, and these may be diminished by improved 

 technic. For fixing Zenker's fluid and corrosive sublimate 

 are available, formalin is not. No special stain is required; 

 any ordinary nuclear stain will answer as well as Koch, Unna 

 or other modifications of Romanowsky. Davis advises that 

 the suspected animal should be kept alive in a cage for obser- 

 vation. If it has hydrophobia it will die in a few days. The 

 brain should be removed after death and examined for Negri 

 bodies and if these are found any person who has been bitten 

 should be given the Pasteur treatment. If the bodies are not 



* For a review of works on rabies see Remlinger. Bulletin de I'lnstitut Pasteur. 

 II., Nos. 19 and 20. 1904. 



f Journ Med. Research. XIV. 1905. pp. 471-489. 

 Uourn A. M. A. July 14, 1906. pp. 87-89. 



