204 MANUAL OF BACTERIOLOGY. 



found - animals should be inoculated. He makes the remark 

 that whatever the nature of these bodies, whether they are 

 parasites or degenerated cells, they are characteristic of hy- 

 drophobia, but are not identical with the virus. For the 

 hypocampus where they are found in''greatest abundance is not 

 more virulent than other parts of the brain in which they may 

 not be found. The stain when used is diluted in the proportion 

 of one drop of the stain to i c.c. of distilled water which has 

 been rendered alkaline by the addition of one drop of a i per 

 cent, solution of potassium carbonate to 10 c.c. of water. This 

 diluted stain is poured over the dried specimen and allowed to 

 remain for from one-half to three hours or even longer. The 

 preparation is then washed in running tap water for one to 

 three minutes, and dried with filter-paper. The cytoplasm of the 

 Negri bodies takes a blue color, the central bacillus and chro- 

 matoid granules stain blue-red or azure. The tinge depends 

 upon the thickness of the specimen. The cytoplasm of the 

 nerve-cells stains blue also, but the nuclei of the nerve-cells 

 stain red, the nucleoli dull blue. 



For diagnostic purposes the method may be shortened as 

 follows: Methyl alcohol, five minutes; equal parts of the 

 Giemsa solution and distilled water, ten minutes. 



In Mallory's method the smears are fixed in Zenker's fluid 

 for one-half hour; rinsed in tap water; one-quarter hour, 95 per 

 cent, alcohol and iodin; 95 per cent, alcohol, one-half hour; 

 absolute alcohol, one-half hour; eosin solution twenty min- 

 utes; rinsed in tap water; methyline blue solution, fifteen 

 minutes; 95 per cent, alcohol, one to five minutes; dry with 

 filter-paper. 



Anna Wessel Williams and Lowden* recommend the use of smear preparations 

 of the brain for examination of the Negri bodies for the reason that the bodies ap- 

 pear more characteristic in such preparations than in preparations made in other 

 ways. The smears are prepared as follows: 



*Williams and Lowden. Journ. Infectious Diseases. Vol. III., 1906. pp 

 452-483. 



