BACILLUS ANTHRACIS. 555 
ens, owls, pigeons, and frogs are but little susceptible 
to infection. Small birds—the sparrow particularly— 
are somewhat susceptible. Man, though subject to 
local infection and occasionally to internal forms of the 
disease, is not as susceptible as some of the Jower ani- 
mals. 
The anthrax bacillus produces in susceptible animals 
a true septicemia. Among test animals mice are the 
most susceptible, succumbing to very minute injections 
of a slightly virulent virus; next guinea-pigs, and lastly 
rabbits, both of these animals dying after inoculation 
with virulent bacilli. Infection is most promptly pro- 
duced by introduction of the bacilli into the circulation 
or the tissues, but inoculation by contact with wounds 
on the skin also cause infection. It is difficult to pro- 
duce infection by the ingestion even of spores; but it 
may readily be caused by inhalation, particularly by the 
inhalation of spores. 
Subcutaneous injections of ‘these susceptible animals 
results in death in from one to three days. Compara- 
tively little local reaction occurs immediately at the 
point of inoculation, but beyond this there is an exten- 
sive cedema of the tissues. Very few bacilli are found 
in the blood, but in the internal organs, and especially 
in the capillaries of the liver, the kidneys, and the 
lungs, they are present in great numbers. In some 
places the capillaries will be seen to be stuffed full of 
bacilli, as in the glomeruli of the kidneys, and hemor- 
rhages, probably due to rupture of capillaries by the 
mechanical pressure of the bacilli which are developing 
within them, may occur. The pathological lesions in 
animals infected by anthrax are not marked except in 
the spleen, which, as in other forms of septicemia, is 
