RABIES 651 



staining inclusions would add weight to such an assumption. We have 

 triturated rabic tissue and shaken it up in anti-formin and seen many 

 free Negri bodies apparently enucleated from the cells in consequence. 

 Such complete extrusion from the cell also is seen in the ordinary smear 

 preparations. It is at least unlikely that a cell-degeneration area would 

 be expelled from the cytoplasm in so clearly outlined and morphologically 

 unaltered a form. The fact that the virus is filtrable, as shown by 

 RemUnger,' Poor and Steinhardt,^ and others, would on the other hand 

 seem to contradict the etiological importance of the Negri bodies unless, 

 with some of the observers named, we assumed them to represent a 

 large stage in the life-cycle of a protozoan parasite, which also occurred 

 in smaller forms. It is a curious fact, also, that Negri bodies are 

 scarce or absent in the spinal cord and cerebrum, though these areas are 

 as virulent or more so than the hippocampus and cerebellum. They 

 are small and hard to find in virus fixe, largest and most plentiful in cases 

 in which the incubation period has been prolonged — as with street-virus 

 infection. Much can be said on both sides, but in analyzing the present 

 experimental facts, it seems fair to say that neither point of view is cer- 

 tain, though the parasitic nature of the Negri bodies seems very likely. 



The cultivation of parasites from rabic tissues has of course been 

 attempted by most bacteriologists who have studied the disease since 

 Pasteur. In all attempts, until very recently, either no results were 

 obtained or else the parasites described could be shown to be pres- 

 ent because of extraneous contamination. Recently Noguchi an- 

 nounced that he has been able to cultivate the virus by employing a 

 technique similar to his methods of cultivating Treponema pallidum and 

 poUomyelitis virus. Into high tubes filled with ascitic fluid a bit of fresh 

 sterile rabbit kidney and a small piece of rabic virus were placed. The 

 ascitic fluid was covered with sterile oil and the tubes incubated at 

 37.5° C. After five days' incubation cloudiness appeared and, with it, 

 minute globoid bodies not unhke those seen in poliomyelitis. After 

 several generations large highly refractile bodies with dark central 

 spots appeared in the cultures, and these Noguchi ^ regards as possibly 

 the parasites and similar to Negri bodies. Opinions are still divided as 

 to the significance of Noguchi's results. However, whatever may be 

 one's opinion regarding the nature of the peculiar bodies visible in his 

 cultures, he has accomplished the feat of preserving the virulence of the 



' Remlinger, Ann. de Finst. Past., xvii, 1903. 



^ Poor and Sieinhardt, Jour, of Inf. Dis., xii, W13. 



' Noguchi, Jour. Exp. Med., xviii, 1913. 



