in a barely perceptible film or in tiny, smooth, discrete colonies. Egg yolk agar surface colonies: Small, circular to slightly irregular, moist, smooth, creamy white, without precipitate or luster. Blood agar surface colonies (aerobic) : Minute, round dew-drops. Hemolysis. Broth: Turbid; slight precipitate. Litmus milk: Softly coagulated, then slowly digested. Little gas is produced. Indole not produced. Carbohydrates not fermented. Nitrites not produced from nitrates. Coagulated albumin: Slow liquefaction. Blood serum: Slow liquefaction with dark- ened, putrid fluid. Brain medium: Blackening and digestion; putrefactive odor. Egg-meat medium: Little gas is produced. Meat first reddened then darkened in 3 days. Digestion apparent in about 24 hours. Nau- seous odor. Tyrosine crystals are abundant after about a week. Anaerobic, aerotolerant, growing feebly on aerobic agar slant. Grows well at 37° C. A cjtolytic exotoxin is produced which causes extensive local necrosis and sloughing on injection. Not toxic on feeding. Produces at least three antigenic com- ponents in toxic culture filtrates: (1) alpha, lethal and necrotizing toxin, (2) beta, col- lagenase, and (3) cysteine-activated pro- teinase which attacks altered collagen (hide- powder or azocoll) but not native collagen (Oakley and Warrack, Jour. Gen. Micro- biol., 4, 1950, 365). Produces an oxygen- labile hemolysin (Howard, Brit. Jour. Exp. Path., 34, 1953, 564). Pathogenic for small laboratory animals. Source: Originally isolated from war wounds, where it induces active necrosis of tissue. Found occasionally in feces and soil. Habitat: Not determined. Apparently widely but sparsely dispersed in soil. 91. Clostridium lacunarum Pr^vot, 1948. (Ann. Inst. Past., 74, 1948, 166.) la.cu.na'rum. L. fem.n. lacuna a ditch, pit or hole, especially one in which water is apt to collect, a lagoon; L. fem.gen.pl.n. lacunarum of lagoons. Straight or curved rods, 0.9 by 4.0 mi- crons, with rounded ends, occurring singly, in pairs or in short chains. Subterminal, ovoid, clostridial spores, 1.5 by 2.0 microns. Encapsulated. Weakly motile. Gram-posi- tive. Gelatin: Liquefaction. Agar deep colonies: Lenticular; gas is produced. Peptone broth: Slightly turbid. VF glucose broth: Abundantly turbid; abundant sediment. Milk: Not coagulated; not changed. Indole and skatole not produced. Hydrogen sulfide produced. Glucose, fructose, maltose, lactose, galac- tose and sucrose are strongly fermented. Mannitol weaklj^ fermented. Nitrites produced from nitrates in the presence of mannitol. Coagulated proteins: Not attacked. Anaerobic, aerotolerant. Optimum temperature, 37° C. Not pathogenic for guinea pigs. Source : Isolated from mud from an Afri- can lagoon. Habitat: Presumably mud. 92. Clostridium tertium (Henry, 1916) Bergey et al., 1923. (Bacillus teriius Henry, Jour. Path, and Bact., 21, 1916, 347; Bergey et al.. Manual, 1st ed., 1923, 332.) ter'ti.um. L. adj. tertius third. Rods, 0.4 to 0.6 by 3.0 to 6.0 microns, oc- curring singly and in pairs, not in chains. Spores ovoid, terminal, swelling the cells. Motile. Gram-positive. Gelatin: No liquefaction. Agar surface colonies (aerobic) : Circular with opalescent, crenated margin. Agar deep colonies: Small, lenticular, regular, smooth. Agar slant (aerobic) : Grayish, filmy, opalescent growth. Broth: Turbid; sediment. Litmus milk: Acid; coagulated; some gas is produced. Clot not digested. Indole not produced. Acid and gas from glucose, fructose, galac- tose, mannose, lactose, maltose, sucrose, arabinose, xylose, trehalose, melezitose, soluble starch, esculin, mannitol, inositol
