578 ' HYDROPHOBIA 



both inside the larger formations and in the general protoplasm 

 of the body are smaller red or violet-red granules, occurring 

 singly or in clumps (kleine Innenformationen). With the eosin 

 dyes named above, and magnifications of 800 to 1000, the 

 smaller bodies appear a homogeneous reddish pink, and in 

 the larger bodies the outlines of the larger internal formations 

 can be recognised (see Plate). With Mallory's stain they present 

 similar appearances with a bluish stippling of the protoplasm. 



The Negri bodies have been found in practically 98 per cent, 

 of cases of street rabies examined by many observers in different 

 parts of the world. Numerous control observations on other 

 toxic conditions of the nervous system, especially where these 

 are characterised by spasms, have been made, and although 

 occasionally, e.g. in tetanus, a somewhat similar appearance has 

 been seen, at present the consensus of opinion is in favour of an 

 experienced observer being able to recognise the Negri bodies as 

 a specific appearance in nerve cells. The bodies occur in all 

 parts of the nervous system, but are most common in the 

 Purkinje cells of the cerebellum, and especially in the cells of 

 the cornu Ammonis (hippocampus major). It is in the last 

 situation, therefore, that they are generally looked for. They 

 are apparently not so readily found, and may be altogether 

 absent, in animals dying from inoculation with the exalted fixed 

 virus.- Hitherto they have not been found in the salivary 

 glands or saliva of a rabid animal. 



While there is a general tendency to recognise the Negri 

 bodies as being specific to rabies, great difference of opinion 

 exists as to their true nature and as to their possessing any 

 etiological significance in the disease. Negri himself looks upon 

 them as protozoa, and the organism has been named by Calkins 

 neuroryctes hydrophobia*. The chief arguments advanced in 

 favour of this position have been the constancy of the occurrence 

 of the bodies in the brains of animals suffering from the natural 

 disease, and their peculiar structure which, such authorities as 

 Golgi state, does not correspond to any cellular degeneration. 

 Against their protozoal nature has been urged their absence 

 from the virulent brains of animals dying from fixed virus, their 

 non-discovery in the infected saliva, and the fact that the virus 

 can pass through a coarse filter. These objections have been met 

 with the argument that the smaller internal formations may be 

 the infective agent in its essential form, and a modification of 

 this view is that the Negri body is a cellular reaction against 

 an invasion with these ultimate forms. The whole question 

 must be looked upon as sub judice. 



