DIAGNOSIS OF BLACK LEG 119g 
Vv 
THE DIAGNOSIS OF BLACK LEG 
The diagnosis of black leg (symptomatic anthrax) is made 
from specimens of the lesions sent to a laboratory by isolating 
the specific organism (8. Chauveaui) either by cultures or by 
guinea-pig inoculations. Cultures should be made anaérobi- 
cally, preferably in glucose agar (Liborius’ Method) or in glucose 
bouillon in the fermentation tube and incubated at about 37° C. 
Growth appears in from 24 to 48 hours, when the cultures should 
be examined. 
The most accurate means of diagnosing black leg is by guinea- 
pig inoculation. Portions of the affected tissue should be 
placed beneath the skin of the pig, or the tissue may bé ground 
in a mortar with sterile bouillon and the suspension injected 
subcutaneously with the hypodermic syringe. If the material 
contains virulent black-leg organisms the pig will die in from 
1 to 3 days. It should then be examined for the lesions of 
black leg, such as subcutaneous cedema and emphysema. A 
microscopic examination of smears made from the diseased 
parts of the guinea pig will reveal the presence of the 
organisms. 
Cover-glass preparations made from the fresh lesions of the 
affected animal will usually reveal the presence of the specific 
organism. In order to be sure of its identification it is neces- 
sary to resort to cultures or guinea-pig inoculations or both. 
It should be remembered that usually the bacilli of black leg 
are not present in the general circulation or in the internal 
organs. In certain cases, however, it can be recovered from the 
spleen or liver. 
If laboratory aid is required to make the diagnosis it is 
necessary to send a portion of the affected muscle. It is also 
desirable to send the spleen. 
