Pathology 369 



Reichel and Engle* stain Negri bodies with the following: 



Sat. ale. sol. methylene violet lo cc. 



Sat. ale. sol. fuchsin 7 drops. 



Sterile water 40 cc. 



The smears of cerebellum or hippocampus are fixed with absolute alcohol and 

 ether and the stain poured on, heated, poured back into the bottle, again poured 

 on, heated and poured back into the bottle, this being done three times, each 

 time for about half a minute. Then wash in water, blot and examine. To 

 examine, a nerve-cell is found with the low power and then examined with the 

 high power. The Negri bodies are brick red. The stain soon fades. Smears 

 kept for any length of time lose the staining reaction. 



Luzzanit gives the following method of staining Negri bodies. 



The tissue to be stained should be fixed in Zenker's solution, imbedded in 

 parafiBne and cut into very thin slices. Mann's stain is used: 



1 : 100 aqueous solution of eosin 4S cc. 



1 : 100 aqueous solution of methylene blue 35 cc. 



Distilled water 100 cc. 



(The solution of eosin and of methylene blue should be kept separately, 

 and only mixed and diluted at the time of using. The diluted mixture does 

 not keep longer than some days, or at best, a few weeks.) 



After the sections are cut, they are fixed to the slides with Mayer's glycerin 

 albumen, the paraffine removed with xylol, the xylol with alcohol, and the 

 alcohol with water. The stain is then applied for some minutes after which the 

 section is rapidly washed in tap water, then in absolute alcohol ; when dehydrated 

 in the absolute alcohol, they are washed in a solution of 



Absolute alcohol 30 cc. 



Saturated solution of caustic soda in absolute alcohol 5 drops. 



until they lose the blue color and become entirely red. They are then given a 

 washing in absolute alcohol, plunged into tap water and then washed with 

 distilled water slightly acidified with acetic acid until they turn blue again. The 

 final steps are absolute alcohol, xylol and Canada balsam. The Negri bodies are 

 red, the cells blue. 



The method should be as applicable for smears or contact spreads 

 as for sections, and for purposes of diagnosis the hippocampal con- 

 volution can be cut across, a clean side touched to the cut surface and 

 removed. Nerve-cells adhere to the glass which is dried and treated 

 as though it had an adhering section of tissue. The Negri bodies are 

 best seen in the processes of the nerve-cells. 



Pathology. — It is generally supposed that the activity of the rabic 

 virus is largely confined to the nervous system, and that from the 

 point of admission to the body it ascends the peripheral nerves to 

 effect its final and fatal influence upon the central nervous system. 

 The seat of inoculation has, therefore, much to do with the facility 

 and rapidity with which the symptoms and termination come on. 



When the virus enters through the skin of the forearm or lower 

 limb, it has a long way to travel, and the period of incubation is long; 

 when it enters about the face, a correspondingly short distance to go, 

 and a correspondingly brief period of incubation. The occurrence 



"■ Personal communication. 



f'Ann, de, I'Inst, Pasteur," 1913, xxxvii, 1039. 



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