116 LABORATORY BACTERIOLOGY 
IV 
THE DIAGNOSIS OF ANTHRAX 
The diagnosis of anthrax can be made from tissues of animals 
recently dead from that disease or from the living animal by 
the following methods : 
1. Bacteriological examination of the tissues or blood. 
2. M‘Fadyean’s stain of cover-glass preparations. 
3. Ascoli’s precipitation method. 
4. Animal inoculation. 
Bacteriological examination. The most favorable media for 
this organism is given in Exercise XXIII. 
As there are many bacteria resembling the bacterium of 
anthrax? it is essential that its identification be based on a very 
careful study of the organism. 
M‘Fadyean’s differential stain. M‘Fadyean has described 
a peculiar staining reaction which he considers of value for the 
microscopic diagnosis of this disease. The reaction is in evi- 
dence when films of blood, exudates, or tissue juice containing 
the bacteria are stained with a simple aqueous solution of 
methylene blue. The method as applied to blood is as follows : 
Place a drop of the blood on a clean slide. The size of the 
drop should be about 2 mm. indiameter. It is spread quickly 
with a platinum needle until it covers an area about 12 mm. 
in diameter. Protect from dust and allow the slide to remain 
until all evidence of moisture has disappeared. When dry, 
heat the preparation by lowering it, film upwards, into the flame 
of a Bunsen burner or an alcohol lamp for a second. Repeat 
1 The junior author summarized the characteristics of these organisms 
in the Report of the New York State Veterinary College, 1909-1910, 
p- 200. The essential difference between Aact. anthracis and the 
pseudo or anthraxlike organisms lies in the morphology (flagella) and 
pathogenesis. 
