422 MICROBIOLOGY 



the entire ganglion, or they may be restricted to a single 

 ganglion cell here and there in the organ. The lesions may be 

 present in one ganglion and not in the other. It is sometimes 

 necessary to examine a number of sections before finding the 

 changes. 



Negri bodies. The diagnosis by the presence of Negri 

 bodies: The numerous examinations and investigations that 

 have been made since 1903 to confirm the discovery of Negri 

 that the bodies which he described possessed a diagnostic, if 

 not causal, relation to rabies, have been practically unanimous 

 in their affirmative findings. We feel justified, therefore, in 

 asserting that the presence of Negri bodies is sufficient evidence 

 on which to diagnose the disease. The results of the different 

 investigations also indicate that the Ammon's horn is the 

 place where these Negri bodies are most constantly present, 

 and therefore the part of the brain to be first examined for 

 them. If they are not found there, an examination should be 

 made of the cerebrum and cerebellum. Those who have worked 

 with these bodies have found that they are not especially diffi- 

 cult to stain or to detect on microscopic examination. Several 

 methods of preparing the material for examination have been 

 suggested, and in the different laboratories where the diagnosis 

 of rabies is being made, slightly different technique is em- 

 ployed. 



In formulating a method to be recommended to all labora- 

 tories, it does not seem within the province of this Committee 

 to accept or to reject any of the technical methods which are 

 giving excellent results in the hands of certain workers, but 

 which are not employed by others. The failure of any of the 

 procedures about to be given depends apparently more upon 

 the worker than upon the method. 



Because of the excellent results obtained by different 

 technique, the Committee recommended as a procedure in diag- 

 nosing rabies from suspected animals sent to laboratories for 

 that purpose, the following : namely, 



1. Examine for Negri bodies, and, if they are found, re- 

 port the disease as positive. 



