chains and filaments disappear. Straight to slightly curved rods, 0.6 to 0.8 by 2.0 to 7.0 microns, with rounded ends. Elliptical, ter- minal spores (arise subterminally), 1.1 by 1.8 to 2.0 microns. Motile. Gram-positive in young cultures. Glucose-gelatin: Liquefaction within seven to twenty-one days. Agar slant: Little or no growth. Glucose j^east agar surface colonies : Irreg- ular outline with woolly or myceloid margin. On moist agar there is a marked tendency to spread forming effuse, amoeboid projec- tions. Center of colony grayish white, opaque, low convex with an effuse trans- lucent marginal zone. Glucose yeast agar deep colonies: Spher- ical, woolly balls, 1.0 mm in diameter; me- dium split by gas evolved. Glucose yeast agar slant: Abundant growth; filiform on dry slants; spreading, with finger-like projections on moist me- dium. Slightly raised, smooth, glistening with butyrous center. Glucose yeast broth: Heavily turbid; heavy, amorphous deposit; much gas. Dis- tinct odor of butanol. Litmus milk: Acid; reduction; gas and clot; frequently stormy coagulation; no digestion. Potato mash: Active fermentation with "head"; complete diastatic action. Indole not produced. Hydrogen sulfide produced in small to moderate amounts in glucose yeast agar in three to seven days. Acid and gas from glucose, galactose, maltose, sucrose, lactose, starch and pectin. Inulin, mannitol, glycerol and calcium lac- tate not attacked. Active retting of flax sterilized in yeast water. Nitrites not produced from nitrates. Ni- trites reduced, presumably to ammonia, in two to three days. Coagulated egg albumin: No visible effect but, after several days, slight softening is usually detected by probing. Brain medium: Some gas; no blackening or digestion. Anaerobic. Grows well between 30° and 37° C. Source: Isolated from Australian flax. Habitat: Presumably soil. 26. Clostridium aerofoetidum (Wein berg and Seguin, 1916) Bergey et al., 1923 (Bacille D, Weinberg, Compt. rend. Soc Biol., Paris, 79, 1916, 117; Bacillus aero foetidus Weinberg and Seguin, ibid., 1028 Bergey et al., Manual, 1st ed., 1923, 327.) a.e.ro.foe'ti.dum. Gr. noun aer air, gas L. adj. foetidus with a bad odor, fetid; M.L. adj. aerofoetidus with bad-smelling gas. Rods, 0.4 to 0.6 by 3.0 to 5.0 microns, oc- curring singly, in pairs and in short chains. Spores rare, ovoid, subterminal, slightly swelling the cells. Motile by means of pe- ritrichous flagella. Gram-positive. Gelatin: Rapid liquefaction. Agar surface colonies (anaerobic) : Circu- lar, transparent, with faint, bluish tint, fimbriate. Agar deep colonies: Lenticular, becoming indented and lobate. Egg yolk agar surface colonies : Irregular, flat, somewhat moist, slightly rough, color- less, without precipitate or luster. Glucose broth: Turbid; sediment. Litmus milk: Acid; slow coagulation fol- lowed by slow peptonization. Gas is pro- duced. Acid and gas from glucose, fructose, galac- tose, mannose, maltose, lactose, xylose, amygdalin, salicin, esculin and glycogen. Sucrose, inulin, glycerol and mannitol not fermented. Nitrites produced from nitrates (Reed, Jour. Bact., 44, 1942, 425). Coagulated albumin: Slow liquefaction. Blood agar: No hemolysis. Blood serum: Liquefaction. Brain medium: Blackened and digested. Meat medium: Reddened, then blackened and slowly digested. Anaerobic. Optimum temperature, between 30° and 35° C. Slightly pathogenic for guinea pigs. Source: Isolated from gaseous gangrene and from feces. Habitat: Not determined. Probably oc- curs in soil.
