522 A MANUAL OF BACTERIOLOGY 



at the site of inoculation a large local lesion forms the muscle is 

 red and hypersemic and contains numbers of gas bubbles and a 

 considerable gelatinous oedema occurs at the margin of the lesion. 

 An active toxin is formed. 



B. histolyticus (Weinberg). A motile, Gram-positive, multi- 

 flagellate, diplobacillus, 3-5 /z in length, forming large sub-terminal 

 spores. It develops well in ordinary culture media ; no gas pro- 

 duction in sugar media ; ferments glucose, Isevulose and maltose. 

 The deep colonies in agar are woolly and arborescent. Gelatin 

 and serum are liquefied. Milk is coagulated and the clot becomes 

 digested in eight to fifteen days. The organism produces a toxin ; 

 1-2 c.c. of a filtered broth culture injected intravenously kills a 

 2-3 kilogram rabbit, often in a few minutes. 



Cultures injected subcutaneously in a guinea-pig cause extensive 

 destruction and liquefaction of the tissues. While incapable 

 itself of producing gas gangrene, it plays a part when present with 

 B. perfringens and B. cedematiens in bringing about softening of 

 the tissues. 



B. aerofetidus (Weinberg). A small slender bacillus 3-5 p. in 

 length. Motility is slight and it is Gram . Spores are sub- 

 terminal and not readily formed. Deep colonies are small and 

 irregular. Gelatin and serum are liquefied. Meat broth : first 

 reddening then blackening, putrid odour. Milk : curdling and 

 gas formation. Glucose, maltose and lactose fermented (Mclntosh), 

 also Isevulose and salicin (Henry). Not pathogenic to guinea-pigs. 



J5. sporogenes (Metchnikoff). Is present in a large proportion 

 of wounds. An actively motile bacillus 3-7 p. in length., and 

 mostly Gram -positive. Spores are readily formed, are oval and 

 central or sub-terminal. Deep colonies are woolly. Meat broth : 

 gas formation with alkaline reaction, digestion and blackening. 

 Serum and gelatin are liquefied. Milk is digested without definite 

 clotting. Glucose, Isevulose and maltose are alone fermented. 

 A feature of this organism is its extraordinary persistency in the 

 presence of other organisms ; it is the most frequent intruder into 

 cultures of other anaerobes, and the mixed cultures may maintain 

 a consistent appearance and the same fermentation reactions for 

 long periods. B. sporogenes tends to enhance the virulence of 

 B. perfringens, though itself frequently non-pathogenic. Some 

 strains, however, are capable of producing a putrid gangrene. A 

 non-specific volatile poison (? a sulphur compound) is formed. 



