CAUSING ACUTE INFECTIONS. 83 
bacilli were isolated from the brushes in several 
instances. 
The anthrax bacillus was the first micro-organ¬ 
ism definitely proved to be the cause of a specific dis¬ 
ease by Davaine in 1863. It is a large straight rod 
with square cut ends, is non-motile, stains by Gram’s 
method and forms spores. It is aerobic. Its growth is 
characteristic. On solid culture media the colonies are 
composed of tangled strands which give them the ap¬ 
pearance of a dishevelled mass of hair and in fluid 
media they grow in long strings. The spores are ex¬ 
tremely resistant and retain their vitality for years. 
In animals the infection is usually intestinal or 
cutaneous. In man the cutaneous infection is in the 
form of a malignant pustule or malignant edema. The 
malignant pustule is characterized by a circumscribed 
swelling, with edema and a black central eschar. It 
is frequently surrounded by a ring of vesicles. 
The malignant edema frequently affects the eye¬ 
lids, lips, and tissues of the neck and chest. It fre¬ 
quently results in gangrene. Anthrax septicemia fre¬ 
quently follows the cutaneous infections. 
Intestinal infection is known to occur from the 
use of infected meat or milk. Several instances of 
anthrax meningitis have been recently reported. 
A pneumonic form of anthrax, known as wool- 
sorter’s disease, occurs from the breathing in of spores 
from dust. 
Among animals immunity may be conferred by 
the injection of attenuated anthrax bacilli. Recently ex- 
Immunity 
