From an agar culture twenty-four hours old. About the margin of the photograph are a number of free spores, × 600.
FIG. 2
Anthrax Pustule. Removed from Arm of Man. (Karg and Schmorl.)
Marked edema of the skin, causing elevation and separation of the papillæ. In the edematous exudate a large number of anthrax bacilli and leukocytes. × 50.
Anthrax bacilli may enter the body through the respiratory organs, through any abraded surface, and possibly even through the alimentary canal. They may also pass through the placenta and affect the fetus in utero. They are too large to pass through the walls of the capillaries of ordinary size; consequently they plug them and produce a mechanical stasis which is rapidly followed by gangrene. From the kidney structures and capillaries, however, they may escape, as bacilli are found in the urine in certain cases of anthrax. (See [Plate IV].)
In man the disease occurs usually as the so-called malignant pustule, or woolsorters’ disease, the latter name being given because of the liability of those individuals who come in contact with the carcasses and hides of diseased animals or their immediate products. The period of incubation is brief—on the average two or three days. The first lesion appears usually on the face, hands, or arms, and is characterized by local discomfort with formation of a small papule, which rapidly becomes a vesicle with an areola of cellulitis about it. This is rapidly followed by induration and infiltration, and these by local gangrene, the result being the separation of a core-like mass, similar to that of carbuncle. The affected area is usually discolored, often quite black. The process is not usually accompanied by suppuration, nor is there the pain of true carbuncle. The lesions tend to spread peripherally, but there is more or less vesication of the surrounding skin. On account of the local ischemia there will always be edema of the affected region, and sometimes the swelling and local disturbance become extreme. These peculiar lesions have given rise to the common name malignant pustule, which is well deserved. At last a line of demarcation becomes manifest, and if the disease progresses favorably the included area is sloughed out, leaving a surface which it is hoped will soon become covered with reasonably healthy granulations.
Absence of pain, and usually of pus, are significant features of anthrax. Should mixed infection occur, however, we are likely to see pus formation. When the disease partakes less of the characteristics of malignant pustule and more of a general infection, the local symptoms may not predominate, but, on the contrary, septic indications may become serious and even fatal. The evidence of more or less toxemia is usually at hand, however, and the toxin of anthrax is almost as destructive of muscle cell integrity as is that of diphtheria.
The local lesions may be single or multiple, but will be met with almost always upon exposed areas of the body.