RABIES, SMALLPOX, VACCINIA AND FILTERABLE VIRUSES 431 



washed with water and covered with a stain made by adding 3 drops of Sat. ale. 

 sol. of basic fuchsin to 10 c.c. of distilled water and then adding 2 c.c. of Loffler's 

 methylene-blue solution. The stain on the slide is then steamed gently and after- 

 ward washed with water and dried. 



As their relation to the nerve-cell is more or less disturbed by such a method 

 it is preferable to fix brain tissue from the region of the cornu ammonis for five to 

 seven hours in Zenker's fluid, then to imbed in paraffin and make sections. These 

 are stained with Giemsa's stain and the Negri bodies are brought out as iliac-red 

 bodies in the blue cytoplasm of the nerve-cells. It is necessary to differentiate in 

 95% alcohol. 



In the Lentz method the 3;* sections, after removal of the paraffin, are flooded 

 with absolute alcohol. They are then stained with a ^% solution of eosin in 60% 

 alcohol for one minute. Wash in water and next stain for one minute in LofHer's 

 methylene blue. Again wash in water. Apply LugoFs solution to the section for 

 one minute and then differentiate alternately in methyl alcohol and water until the 

 section is pink. After washing in water, again stain with LofBer's blue for one-half 

 a minute, then wash in water and dry carefully with filter-paper. Now differentiate 

 in alkaline alcohol (i drop of a 5% solution NaOH in 30 c.c. absolute alcohol) until 

 the section is pink, then quickly differentiate in acid alcohol (i drop 50% acetic 

 acid in 30 c.c. absolute alcohol) until a slight blue outline to the ganglion cells is 

 obtained. Treat rapidly with absolute alcohol and xylol and mount in balsam. 

 The Negri bodies show as light carmine pink bodies on the light blue ground of the 

 ganglion cells. In the interior of the pink bodies dark blue dots or rings may be 

 observed. 



This method can also be used for brain smears. 



In addition to examining for the Negri bodies, a rabbit may be inoculated sub- 

 durally with a sterile salt-solution emulsion of the medulla of the dead dog. 



If the brain and medulla of the dog are to be sent to a laboratory 

 for examination they should be packed in ice or placed in glycerine. 

 Take of glycerine one part and one part water. Sterilize the diluted 

 glycerine by boiling, allow to cool, and drop the pieces of brain tissue 

 into this. This does not kill the virus. 



When from advanced putrefaction, or otherwise, the Negri bodies cannot be 

 found the changes in the Gasserian ganglia may give a diagnosis. In typical lesions 

 the ganglion cells are more or less completely destroyed and replaced by cells of 

 other types. 



When a person is bitten by a dog suspected of being rabid the following 

 simple measures should be instituted. The dog should be kept under observation 

 in a safe quiet place and will show clinical evidence of rabies within five days and 

 will die shortly afterward in case rabies exists. When the animal dies the head 

 and several inches of the neck should be removed and packed in ice and sent to the 

 nearest laboratory. 



Antirabic serum has been prepared by injecting sheep with emulsions of rabbits' 

 cord and brain at first intravenously, then subcutaneously. 



