622 



ORDER IV. EUBACTERIALES 



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 and Gordon, unpublished data).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. 



