fermented. Sucrose, salicin, dulcitol and inositol not attacked. Nitrites not produced from nitrates. Coagulated albumin: No liquefaction. Blood agar: No hemolysis. Blood serum: No liquefaction. Brain medium (Hibler) : No blackening or digestion even in the presence of an iron strip. Anaerobic. Optimum temperature not determined. Grows well both at 37° C. and at room tem- perature. Not pathogenic for white mice, guinea pigs or rabbits. Distinctive character: Submerged colo- nies extremely gummatous. Source: Isolated once from gaseous gan- grene and twice from normal human feces (adult and infant). Habitat: Decomposing organic matter, so far as known. Indole not produced (Duffett, Jour. Bact., 29, 1935, 576). Acid and gas from glucose, galactose, fructose, maltose, lactose, sucrose, inulin, salicin and starch. Glycerol and mannitol not fermented. Records wM-y in regard to action on lactose, inulin and salicin. Coagulated albumin: No liquefaction. Blood serum: No liquefaction. Brain medium: No blackening or diges- tion. Meat medium: Reddened; no blackening or digestion. Anaerobic. Optimum temperature, not recorded. Grows well at 37° C. A weak exotoxin is produced. Pathogenicity for guinea pig variable and commonly lost in cultivation. Source: Isolated from war wounds, appen- dicitis and once from black-leg of sheep. Habitat: Presumably widely distributed. 7. Clostridium fallax (Weinberg and Seguin, 1915) Bergey et al., 1923. (Bacille A, Weinberg and Seguin, Compt. rend. Soc. Biol., Paris, 78, 1915, 277; Bacillus fallax Weinberg and Seguin, ibid., 686; Bergey et al., Manual, 1st ed., 1923, 325; Clostridium pseudo-fallax Prevot and Loth, Ann. Inst. Past., 67, 1941, 244.) fal'lax. L. adj. fallax deceptive, false. Rods, 0.6 by 1.2 to 5.0 microns, occurring singly or rarely in pairs. Spores, rarely ob- served, are ovoid, eccentric to subterminal and swell the cells. Encapsulated in body fluids. Motile by means of peritrichous fla- gella. Gram-positive. Gelatin: No liquefaction. Glucose agar surface colonies (anaerobic) : Circular, flat; transparent, crenated margin. Glucose agar deep colonies: Lenticular, bean-shaped, irregular, smooth. Agar slant (anaerobic) : Grayish film. Broth: Poor growth; slight, diffuse tur- bidity. Glucose broth: Abundant turbidity and gas. Clearing by sedimentation. Litmus milk: Acid; slowly coagulated. Litmus reduced. Clot channeled by gas but not digested. 8. Clostridium difficile (Hall and O'Toole, 1935) Prevot, 1938. {Bacillus diffi- cilis Hall and O'Toole, Amer. Jour. Dis. Child., 49, 1935, 390; Clostridium difficilis (sic) Prevot, Ann. Inst. Past., 61, 1938, 84.) dif.fi'ci.le. L. adj. difficilis difficult. Heavily bodied rods. Spores elongated and subterminal, slightly swelling the cells. Actively motile. Gram-positive. Gelatin: No liquefaction. Agar deep colonies: Minute, flat, opaque discs, becoming lobate. Egg yolk agar surface colonies: Irregular, flattened, dry, roughened, somewhat gran- ular, with little or no color. No precipitate in the agar nor luster on the colony. Milk: Poor growth. Gas produced in traces, but milk unchanged. Acid and gas from glucose, fructose, man- nitol, salicin and xylose. Traces of gas but no acid from galactose, maltose, sucrose, lactose, raffinose, inulin and glycerol. Nitrites produced from nitrates (Reed, Jour. Bact., 44, 1942, 425). Coagulated albumin: No liquefaction. Blood agar surface colonies (anaerobic) : Irregular, flat; no hemolysis. Blood serum: No liquefaction.
