608 RABIES AND THE NEGRI BODIES 



with filter paper. If the smear is thick the "bodies" may come out a 

 little more clearly by dipping in 50 per cent, methyl alcohol before 

 washing in water, then the washing need not be as thorough. By 

 this method of staining the cytoplasm of the "bodies" stains blue and 

 the central bodies and chroma toid granules stain a blue red or azure. 

 Generally the larger "bodies" are a darker blue than the smaller; the 

 smallest of all may be very light. The stain varies somewhat according 

 to the thickness of the smear. Some have a robin's egg blue tint, but 

 this is due to long fixation in the methyl alcohol. In this case the 

 red blood cells may have a greenish tint. The cytoplasm of the nerve 

 cells stains blue also, but with a successfully made smear the cytoplasm 

 is so spread out that the outline and structure of most of the "bodies" 

 are seen distinctly within it. The nuclei of the nerve cells are stained 

 red with the azure, the nucleoli a dull blue, the red blood cells a pink 

 yellow, more pink if the decolorization is used. The "bodies" have 

 an appearance of depth, due to their slightly refractive qualities. 



For diagnostic purposes this method of staining may be shortened 

 as follows: Methyl alcohol, five minutes, equal parts of the Giemsa 

 solution and distilled water, ten minutes. In this way "bodies" are 

 generally brought out well enough for diagnosis, and sometimes the 

 structure shows distinctly. It is always well, however, to make smears 

 enough for the longer method of staining, in case the shorter should 

 prove unsatisfactory. 



(6) The eosin-methylene blue method recommended by Mallory. 

 The smears are fixed in Zenker's solution for one-half hour; after 

 being rinsed in tap water they are placed successively in 95 per cent, 

 alcohol + iodin, one-quarter hour; 95 per cent, alcohol, one-half 

 hour; absolute alcohol, one-half hour; saturated watery eosin solution, 

 twenty minutes, rinsed in tap water; alkaline methylene-blue solution, 

 fifteen minutes; differentiated in 95 per cent, alcohol lasting from one 

 to five minutes, and dried with filter paper. With this method of 

 staining the cytoplasm of the "bodies" is a magenta, light in the 

 small bodies, darker in the larger; the central bodies and chromatoid 

 granules are very dark blue, the nerve cytoplasm a light blue, the 

 nucleus a darker blue, and the red blood cells a brilliant eosin pink. 

 With more decolorization in the alcohol the "bodies" are not such a 

 deep magenta and the difference in color between them and the red 

 blood cells is not so marked. 



The "bodies" and the structure are often more clearly defined with 

 this method, and perhaps on the whole it is better to use it for making 

 diagnoses; but when there are only tiny "bodies" present, or when 

 the brain tissue is old and soft, the Giemsa stain seems to be the 

 more successful. Above all, when one wishes to study the nature of 

 the central structures and granules the Giemsa stain must be used. 

 Both methods are strongly recommended. 



The technique of the section work is as follows: (1) The small 

 pieces are left in Zenker's fluid for three to four hours; (2) washed 



