BACILLUS ANTHRACIS SYMPTOMATICI. 565 
are, as a rule, naturally immune to the disease. The 
guinea-pig is the most susceptible of test animals. 
When susceptible animals are inoculated subcutane- 
ously with pure cultures of this organism, with spores 
attached to a silk thread, or with bits of tissue from 
the affected parts of another animal dead of the disease, 
death ensues in from twenty-four to thirty-six hours. 
At the autopsy a bloody serum is found in the subcuta- 
neous tissues extending from the point of: inoculation 
over the entire surface of the abdomen, and the muscles 
present a dark-red or black appearance, even more in- 
tense in color than in malignant oedema, and there is a 
considerable development of gas. The lymphatic glands 
are markedly hyperemic. 
The disease occurs chiefly in cattle, more rarely in 
sheep and goats; horses are not attacked spontaneously 
—1i. é., by accidental infection. In man, infection has 
never been produced, though ample opportunity, by 
infection through wounds in slaughter-houses and by 
the ingestion of infected meat, has been given. The 
usual mode of natural infection by symptomatic an- 
thrax is through wounds which penetrate not only the 
skin but the deep intercellular tissues; some cases of 
infection by ingestion have been observed. The patho- 
logical findings present the conditions above described 
as occurring in experimental infection. 
Symptomatic anthrax, like anthrax and malignant 
cedema, is a disease of the soil, but it shows a more 
limited endemic distribution than the first, and is differ- 
ently distributed over the earth’s surface than the sec- 
ond of these diseases, being confined especially to places 
over which infected herds of cattle have been pastured. 
It is doubtful whether the bacilli are capable of devel- 
