QUARTER-EVIL. 401 



without the ordinary signs of decomposition being present. The 

 production of an extracellular toxin by this organism, with ex- 

 tremely potent action on the nervous system, is a fact of great 

 scientific interest, and has a bearing on the etiology of other 

 obscure nervous affections. 



Quarter-evil (German, Rauschbrand ; French, Charbon 

 S ymptomatique) . 



The characters of the bacillus need be only briefly described, as, so far as 

 is known, it never infects the human subject. The natural disease, which 

 specially occurs in certain localities, affects chiefly sheep, cattle, and goats. 

 Infection takes place by some wound of the surface, and there spreads in the 

 region around, inflammatory swelhng attended by bloody oedema and em- 

 physema of the tissues. The part becomes greatly swollen, and of a dark, 

 almost black, colour. Hence the name blackleg by which the disease is some- 

 times known. The bacillus which produces this condition is present in large 

 numbers in the affected tissues, associated with other organisms, and also 

 occurs in small numbers in the blood of internal organs. 



Bacillus anthracis symptomatici. — The bacillus morphologically closely 

 resembles that of malignant cedema. Like the latter, also, it is a strict ana- 

 erobe, and its conditions of growth as regards temperature are also similar. 

 It is, however, somewhat thicker, and ^ . — 



does not usually form such long fila- . / I :^ ■-, 



ments. Moreover the spores, which ~ \ 



are of oval shape and broader than » ^ ^ \^ 



the bacillus, are almost invariably situ- \^ ''^' 



ated close to one extremity, though ** "X •^ ^■ 



not actually terminal (Fig. 135). The » '\ ^- «•. \ 



characters of the cultures, also, resem- A *■ ■^ 



ble those of the bacillus of malignant 1/0 " 



ffidema, but in a stab-culture in glu- ^ "^^^ I 



cose agar there are more numerous and ai ' ~ ^' 



longer lateral offshoots, the growth '^ "«* 



being also more luxuriant (Fig. 1 34, C ). 

 This bacillus is actively motile, and 



possesses numerous lateral fiagella. fig. 135. — Bacillus of quarter-evil, show- 

 It does not retain the stain by Gram's ing spores. From a culture in glucose agar, 

 method incubated for three days at 37^ C. Stained 



with weak carbol-fuchsin. X 1000. 



The disease can be readily pro- 

 duced in various animals, e.g. guinea-pigs, by inoculation with the affected 

 tissues of diseased animals, and also by means of pure cultures, though an 

 intramuscular injection of a considerable amount of the latter is sometimes 

 necessary. The condition produced in this way closely resembles that in 

 malignant oedema, though there is said to be more formation of gas in the 

 tissues. Rabbits are very iminune against this disease, whilst they are com- 

 paratively susceptible to malignant oedema. As in the case of tetanus, inocu- 



