DIAGNOSIS 607 



spread of the organisms. These tiny budded forms similar to "swarm 

 spores" are probably motile and pass quickly to other host cells. 



The Rapid Microscopic Diagnosis of Rabies. Williams and Lowden 

 worked out a rapid method of diagnosticating microscopically rabies, 

 and an almost identical method by Frothingham was published about 

 the same time. 



The author has used their smear method since the fall of 1906 and 

 has found it very satisfactory and reliable, and it is highly recom- 

 mended in all cases where a rapid microscopic diagnosis is necessary. 

 The steps' of Williams' and Lowden's method are as follows: 



1. Glass slides and cover-glasses are washed thoroughly with soap 

 and water, then heated in the flame to get rid of greasy substance. 



2. A small bit of the gray substance of the brain to be examined is 

 cut out with a small, sharp pair of scissors and placed on the slide 

 about one inch from the end, so as to leave enough room for a label. 

 The cut in the brain should be made at right angles to its surface and 

 a thin slice taken, avoiding the white matter as much as possible. 



3. A cover-slip placed over the piece of tissue is pressed upon it 

 until the brain substance is spread out in a moderately thin layer, 

 then the cover-slip is moved slowly and evenly over the slide to the 

 end opposite the label. Only slight pressure should be used in making 

 the smear, but slightly more should be exerted on the cover-glass 

 toward the label side of the slide, thus allowing more of the nerve 

 tissue to be carried farther down the slide and producing better 

 spread nerve cells. If any thick places are left at the edge of the 

 smear, one or two of them may be spread out toward the side of 

 the slide with the edge of the cover-glass. If the first smear does 

 not turn out successfully others should be made until a satisfactory 

 one is obtained. 



4. For diagnosis work such a smear should be made from at least 

 three different parts of gray matter of the central nervous system: 

 First, from the cortex in the region of the fissure of Rolando or in 

 the region corresponding to it (in the dog the convolution around 

 the crucial sulcus); second, from Ammon's horn; third, from the 

 cerebellum. 



5. The smears are dried in air and subjected to one or both of the 

 following staining methods : 



(a) Giemsa's Solution. The smears are fixed in methyl alcohol 

 (commercial is just as good as pure) for about five minutes. The 

 staining solution recommended last by Giemsa is as follows: 1 drop 

 of the stain to every c.c. of distilled water made alkaline by the 

 previous addition of 1 drop of a 1 per cent, solution of potassium 

 carbonate to 10 c.c. of water. This is poured over the slide and 

 allowed to stand from one-half to three hours. The longer time 

 brings out the structure better, and in twenty-four hours well-made 

 smears are not overstained. After the stain is poured off the smear 

 is washed in running tap water for one to three minutes, and dried 



