62 CLINICAL BACTERIOLOGY AND H^EMATOLOGY 



ANTHRAX 



Anthrax occurs in man in three forms.* The most common 

 is cutaneous anthrax, or, as it is sometimes called, malignant 

 pustule. Pulmonary anthrax, or wool-sorter's disease, is 

 much rarer, and intestinal anthrax rarer still. The practi- 

 tioner will find the greatest assistance from a bacteriological 

 examination in the cutaneous form of the disease; he may 

 search for the specific bacillus in the sputum in a supposed case 

 of wool-sorter's disease, but he must be careful in his inter- 

 pretation of his result, as bacilli which might be mistaken by 

 an untrained observer, relying on the morphological appear- 

 ances alone, sometimes occur in the sputum. The search for 

 bacilli in the faeces in a supposed case of intestinal anthrax 

 must be relegated to an expert. 



The true nature of a case which is examined post mortem 

 can easily be determined bacteriologically; the cut surface of 

 the liver or spleen should be rubbed upon a clean slide, and 

 the films treated secundum art em. They will probably show, 

 the bacilli in large numbers. Sections may also be cut and 

 stained by Gram's method (see p. 226). 



In the later stages of any infection with anthrax the bacilli 

 may be found in the blood. They may be apparent on 

 examination of stained films, or may be demonstrated by cul- 

 tural methods similar to those used in the diagnosis of malig- 

 nant pustule. 



The anthrax bacillus varies considerably in length, but is 

 always a large organism, and may be considerably longer 

 than the diameter of a red blo'od-corpuscle. It is much thicker 

 than the bacilli which have been dealt with hitherto (other 

 than B. perfringens and B. oedematis maligni), and it is in- 

 variably straight. The ends of these bacilli are cut sharply at 

 right angles to the sides of the organism, and may be even 

 somewhat concave ; this is a most characteristic feature. The 

 anthrax bacillus stains by Gram's method (Plate I., Fig. 4). 



In cultures the appearances are somewhat different. Here 

 the bacilli are frequently arranged in long chains which have 

 an appearance which has been compared to a bamboo stem; 

 chains occur in the blood or in the inflammatory exudate, but 

 are usually much shorter than those seen in cultures. But 



* Several cases of a meningeal form have recently been recorded. 

 * 



