Biotin necessary for growth. Lecithinase reaction variable. Aerobic, facultatively anaerobic. Growth with vigorous production of gas in glucose broth under anaerobic conditions. Temperature relations: Optimum, be- tween 28° and 35° C. Maximum, for the majority of the strains, 40° C. No growth at 45° C. Antibiotic substance (polymyxin) ob- tained from cultures of a certain strain (Stansly, Shepherd and White, Bull. Johns Hopkins Hosp., 81, 1947, 43; also see Stansly and Schlosser, Jour. Bact., 54, 1947, 549). Source: Isolated from grain, soil and pas- teurized milk. Habitat : Widely distributed in soil, water, milk, feces and decaying vegetables. 13. Bacillus macerans Schardinger, 1905. (Rottebazillus 1, Schardinger, Wien. Klin. Wochnschr., 17, 1904, 207; Schar- dinger, Cent. f. Bakt., II Abt., U, 1905, 772.) ma'ce.rans. L. part. adj. macerans to soften by steeping, to ret. Rods, 0.5 to 0.7 by 2.5 to 5.0 microns, not in chains. Motile. Gram-variable. Spores, 1.0 to 1.5 by 1.2 to 2.5 microns, ellipsoidal, subterminal to terminal. Spore wall thick and easily stained. Sporangia definitely swollen, clavate. Gelatin stab: Liquefaction variable owing to the low temperature. Gelatin agar streak plate: Fair to good zone of hydrolysis. Agar colonies: Thin, transparent to whit- ish, spreading, irregular. Rough stage small and compact. Agar slants: Growth thin, spreading or restricted, inconspicuous to whitish. Glucose agar slants: Growth heavier than on agar, usually with the production of gas. Glucose nitrate agar slants: Very scant, if any, growth. Proteose-peptone acid agar slants: No growth. Soybean agar slants: Growth usually as good as or better than on agar; sometimes gas is produced. Stock culture agar slants: Growth gen- erally better than on agar. Usually no gas Broth: Turbidity light, uniform to gran- ular, with or without flocculent sediment. NaCl broth: No growth in 5 per cent NaCl. Milk: Acid and gas. No visible peptoniza- tion. Milk agar streak plate: Very small, if any, zone of hydrolysis of the casein. Potato: Inconspicuous or scant growth with the production of much gas 'and de- composition of the potato. Indole not produced. Acid and usually gas (with ammonium salts as source of nitrogen) from arabinose, rhamnose, xylose, glucose, sucrose, lactose, mannitol and sorbitol (the production of gas can best be demonstrated by growing the cultures at 37° C. on the following me- dia: agar plus 1 per cent potato starch, po- tato plugs or wheat mash as used for the production of crj'stalline dextrins). Starch hydrolyzed. Crystalline dextrins produced from starch. Acetylmethylcarbinol not produced. Ace- tone and ethanol produced. pH of glucose broth cultures is 5.0 or lower. Citrates not utilized. Methylene blue reduced and then com- pletely reoxidized. Nitrites produced from nitrates. No gas produced in nitrate broth under anaerobic conditions. Biotin and thiamine are essential for growth. Lecithinase reaction negative or faint. Aerobic, facultatively anaerobic. Usually there is growth with the production of gas in glucose broth under anaerobic conditions (neutral broth is better than the alkaline broth generally prepared for this test). Temperature relations: Optimum, be- tween 28° and 40° C. Maximum, usually between 45° and 50° C. Source: Isolated from vats in which flax was retting. Habitat: Widely distributed in soil, watei', decomposing starchy materials, retting flax, etc. 14. Bacillus alvei Cheshire and Cheyne,
