arborescent, with coral-red pigment. Colo- nies near aerobic layer are more pigmented. Agar slants (in vacuum) : Round colonies with irregular edges, non-pigmented. Colo- nies become coral-colored if air is intro- duced into the tube. Peptone broth: Slightly turbid; colorless sediment; pigment develops on addition of glucose. Glucose broth: Abundantly turbid; gas liberated; no pigment produced under ana- erobic conditions. Milk: Coagulated in 24 hours, clot not digested (Prevot and Raynaud, ihid., 183); coagulation with digestion (Prevot and Sansonnens, Ann. Inst. Past., 73, 1947, 1044). Indole and skatole not produced. Hydrogen sulfide produced. Glucose, fructose, maltose, galactose, su- crose, lactose, arabinose, xylose, mannitol, sorbitol, dulcitol, glycerol, starch and inulin are fermented. Pectin not attacked (Prevot and Ray- naud, op. cit., 1944, 183); pectin attacked (Prevot and Raynaud, Compt. rend. Acad. Sci., Paris, 222, 1946, 1531). Produces butyric and formic acids; lactic acid not produced (Prevot and Raynaud, op. cit., 1944, 183); fermentation type: for- mic-butyric-lactic with alcohol and acetone or acetic-isobutyric-lactic with acetone (Prevot and Sansonnens, op. cit., 1947, 1044); acetic, butyric and formic acids, ethyl and butyl alcohols and acetone (Pre- vot and Raynaud, op. cit., 1946, 1531). Acetylmethylcarbinol not produced. Nitrites not produced from nitrates. Coagulated serum: Not attacked. Anaerobic. Not pathogenic for mice or guinea pigs. Source: Isolated from the serum from a mouse inoculated with Paris street dust (Pr6vot and Raynaud, op. cit., 1944, 182) and from African soil (Prevot and Sanson- nens, op. cit., 1947, 1044). Habitat: Soil. 74. Clostridium aurantibutyricum Hellinger, 1944. (Commemorative Vol. to Dr. Ch. Weizmann's 70th Birthday, Nov., 1944, 46; also see Jour. Gen. Microbiol., /, 1947, 203.) au.ran.ti.bu.ty'ri.cum. M.L. noun au- rantium the orange; M.L. noun acidum hu- tyricum butyric acid; M.L. adj. aurantibu- tyricus (probably intended to mean) the golden organism producing butyric acid. Straight rods, 0.5 by 4.7 microns at 30° to 0.5 by 9.4 microns at 37° C. Spores sub- terminal and ovoid (0.9 by 2.1 microns), swelling the cells. Spore-bearing cells are motile and mostly spindle-shaped. Motile by means of peritrichous flagella. Clostridia are granulose-positive. Gram-positive. Gelatin: Liquefaction. Glucose yeast agar surface colonies: Slightly granular with orange-red pigment; sometimes pink, deepening to pale orange on continued anaerobic incubation. Potato slant: Not disintegrated. Carrot slant : Softening and rotting within 48 hours. Maize mash: Active gas production with distinct pink coloration; good but incom- plete diastatic action. Acid and gas from xylose, galactose, glu- cose, sucrose, lactose, maltose, pectin and starch. Cellulose, inulin, mannitol, glycerol and sorbitol not fermented. Products of maize (starch) and glucose fermentation : Main products are acetic and butyric acids. Acetone, butanol, ethanol, acetone and iso-propanol are formed in lesser amounts. Lactic and formic acids and acetylmethylcarbinol produced only in slight or negligible amounts. Nitrites not produced from nitrates. Anaerobic. Optimum temperature, 30° C. Distinctive characters (differentiation from Clostridium felsmeum Bergey et al. and C. roseum McCoy and McClung) : Partial diastatic action in maize mash; lower yield of neutral fermentation products from car- bohydrates; inability to ferment inulin; failure to digest potato tissue; inability to reduce nitrates; optimum temperature, 30° C. Source: Isolated from stems of South African hibiscus and from English flax. Habitat: Soil. 75. Clostridium felsineum (Carbone and Tombolato, 1917) Bergey et al., 1930. {Bacillus felsineus Carbone and Tombolato, Le Staz. Sper. Agrar., Ital., 50, 1917, 563;
