7. Bacillus pumilus Gottheil, 1901. (Cent. f. Bakt., II Abt., 7, 1901, 681.) pu'mi.lus. L. adj. -pumilus little, diminu- tive. Rods, 0.6 to 0.7 by 2.0 to 3.0 microns, not in chains. Stain uniformly. Not encapsu- lated. Motile. Gram-positive. Variations: Chains and filaments. Encapsulated. Gram- variable. Spores, 0.5 by 1.0 micron, ellipsoidal to cylindrical, central or para-central, thin- walled. Readily formed. Variations: 0.6 to 0.8 by 0.8 to 1.5 microns. Sporulation slow (certain strains sporulate best on soybean agar). Sporulation in certain strains poor on media made with highly refined agar; much better when crude agar is used or when soil extract is added to the refined agar (Smith and Gordon, unpublished data). Sporangia not definitely swollen. Gelatin stab: Slow liquefaction. Gelatin agar streak plate: Wide zone of hydrolysis. Agar colonies: Smooth, thin, flat, spread- ing, dendroid, translucent. Variations: Small to pinpoint, nonspreading, dense. Agar slants: Growth smooth, thin, glis- tening, spreading, non-adherent. Fre- quently yellowish. Variations: Rough, dull, tough or wrinkled. Glucose agar slants: Growth usually the same as on agar, sometimes heavier or scantier. Glucose asparagine agar slants: Growth abundant. Variations: Scant or no growth. Glucose nitrate agar slants: Growth usually scant. Soybean agar slants: Growth more abun- dant than on agar, soft, yellow. Variations: Rough, red or colorless. Tyrosine agar slants: Same as agar slants. Broth: Turbidity uniform, with or with- out ring or fragile pellicle. Variations: Tur- bidity flocculent. Broth clear with rough pellicle. NaCl broth: Growth in 7 per cent NaCl; in a few cases growth in 10 per cent. Milk: Peptonized, sometimes coagulated. Milk agar streak plate: Usually there is a wide zone of hydrolysis of the casein. Potato: Growth smooth, thin, soft, spreading, moist to slimy, yellow to brown. Potato darkened. Variations: Rough, dry, wrinkled, pink or red. Acid but no gas (with ammonium salts as source of nitrogen) from arabinose, xy- lose, glucose, sucrose and mannitol. Usually no acid from lactose. Starch not hydrolyzed. Acetylmethylcarbinol is produced. pH of glucose broth cultures is 5.0 to 8.4. Citrates utilized as sole source of carbon. Nitrites not produced from nitrates. No gas produced in nitrate broth under ana- erobic conditions. Biotin essential for growth. Lecithinase not produced. Aerobic, certain strains facultatively anaerobic. Growth scant, if any, in glucose broth under anaerobic conditions; pH is 5.5 or higher at 14 days. Temperature relations: Optimum, be- tween 28° and 40° C. Maximum, between 45° and 50° C. Source: Isolated from plants. Habitat: Widely distributed in soil, dust and cheese; also common as a laboratory contaminant. 8. Bacillus coagulans Hammer, 1915. (Iowa Agr. Exp. Station, Research Bull. 19, 1915, 129; also see Sarles and Hammer, Jour. Bact., 23, 1932, 301.) co.a'gu.lans. L. part. adj. coagulans curd- ling, coagulating. Rods, 0.6 to 1.0 by 2.5 to 5.0 microns, not in chains. Stain uniformly. Motile. Gram- positive. Variations: Rods, 0.5 to 1.2 by 2.0 to 6.0 microns, to filaments. Gram-varia- ble. Spores, 0.9 to 1.0 by 1.2 to 1.5 microns, ellipsoidal, thin-walled, subterminal to terminal. Variations: 0.8 to 1.1 by 1.2 to 2.0 microns. Kidney-shaped or cylindrical. Sporulation poor when highly refined agar is used in the medium; much better with crude agar or when soil extract is added to the refined agar (Smith and Gordon, unpub- lished data). Sporangia definitely swollen in some cases, not swollen in others. Gelatin agar streak plate: Zone of hy- drolysis small, if any.
