310 ANTHRAX 



usually is seen among those whose trade leads them to handle 

 the carcases or skins of animals which have died of the disease. 

 It occurs in two principal forms, the main difference between 

 which is due to the site of entrance of the organism into the 

 body. In one, the path of entrance is through cuts or abrasions 

 in the skin, or through the hair follicles. A local condition 

 called a "malignant pustule" develops, which may lead to a 

 general infection. This variety occurs chiefly among butchers 

 and those who work among hides (foreign ones especially). In 

 Britain the workers of the latter class chiefly liable are the hide- 

 porters and hide- workers in South-Eastern London. In the other 

 variety of the disease the site of infection is the trachea and 

 bronchi, and here a fatal result almost always follows. The 

 cause is the inhalation of dust or threads from wool, hair, or 

 bristles, which have been taken from animals dead of the disease, 

 and which have been contaminated with blood or secretions con- 

 taining the bacilli, these having afterwards formed spores. This 

 variety is often referred to as " woolsorter's disease," from its 

 occurring in the centres of the woolstapling trade (in England, 

 chiefly in Yorkshire), but it also is found in places where there 

 are hair and brush factories. 



(1) Malignant Pustule. This usually occurs on the exposed 

 surfaces the face, hands, fore-arms, and back, the last being a 

 common site among hide-porters. One to three days after 

 inoculation a small red painful pimple appears, soon becoming a 

 vesicle, which may contain clear or blood-stained fluid, and is 

 rapidly surrounded by an area of intense congestion. Central 

 necrosis occurs and leads to the malignant pustule proper, which 

 in its typical form appears as a black eschar often surrounded 

 by an irregular ring of vesicles, these in turn being surrounded 

 by a congested area. From this pustule as a centre subcutaneous 

 oedema spreads, especially in the direction of the lymphatics ; 

 the neighbouring glands are enlarged. There is fever with 

 general malaise. On microscopic section of the typical pustule, 

 the central eschar is noticed to be composed of necrosed tissue 

 and degenerating blood cells ; the vesicles are formed by the 

 raising of the stratum corneum from the rete Malpighi. Beneath 

 them and in their neighbourhood the cells of the latter are 

 swollen and cedematous, the papillae being enlarged and flattened 

 out and infiltrated with inflammatory exudation, which also 

 extends beneath the centre of the pustule. In the tissue next 

 the eschar necrosis is commencing. The subcutaneous tissue is 

 also cedematous, and often infiltrated with leucocytes. The 

 bacilli exist in the periphery of the eschar and in the neigh- 



