Ann. de Micrographie, 1, 1889, 552; Migula, Syst. d. Bakt., 2, 1900, 726.) pas.teur'i.i. M.L. gen.noun pasteurii of Pasteur; named for Louis Pasteur, a French chemist and bacteriologist. Description taken from Lohnis and Kuntze (Cent. f. Bakt., II Abt., 20, 1908, 684), Gibson (Jour. Bact., 28, 1934, 295 and 313; also see ibid., 29, 1935, 491) and Smith, Gordon and Clark (op. cit., 1952). Rods, 0.6 to 0.9 by 1.5 to 3.5 microns (1.0 to 1.5 by 4.0 to 5.0 microns, Lohnis and Kuntze), with rounded ends, usually not in chains. Motile. Gram-variable. Spores, 1.0 to 1.2 microns in diameter, round, terminal to subterminal. Sporangia usually bulged and clavate. Urea gelatin stab : Slow, crateriform lique- faction. Urea gelatin streak plate: Visible zone of hydrolysis. Urea agar colonies: Small, round, not distinctive. Urea agar slants: Growth thin, restricted, translucent. Urea agar slants with pH 6.0 or less : No growth. Urea soybean agar slants: Good growth, heavier than on agar. Urea broth: Turbidity uniform, moderate to heavy. NaCl urea broth: Growth in 10 per cent NaCl. Urea milk agar streak plate: Hydrolysis of the casein is variable. No acid from carbohydrates with agar plus urea as base medium. Starch not hydrolyzed. Acetylmethylcarbinol not produced (urea added) . Nitrites produced from nitrates in urea nitrate broth. Gas production variable under anaerobic conditions. Urease produced. Thiamine plus biotin or nicotinic acid are essential for growth. Alkaline reaction and usually ammonia or urea are also essential. Aerobic, facultatively anaerobic. Growth in urea glucose broth under anaerobic con- ditions. Temperature relations: Optimum, be- tween 28° and 35° C. Maximum, between 37° and 40° C. Source: Isolated from decomposing urine. Habitat: Widely distributed in soil, ma- nure and sewage. Genus II. Clostridium Prazmowski, 1880.* (Untersuchungen iiber die Entwickelungsgeschichte und Fermentwirkung einiger Bacterien-Arten, Inaug. Diss., Leipzig, 1880, 23.) Clos.tri'di.um. Gr. noun closter a spindle; M.L. dim. noun Clostridium a small spindle. Rods, often swollen at sporulation, producing clostridial, plectridial, clavate or navicular forms. Motile by means of peritrichous flagella; occasionally non-motile. Generally Gram- positive. Many species are saccharolytic and fermentative, producing various acids (gen- erally butyric and acetic), gases (CO2 , H2 and, at times, CH4) and variable amounts of neutral products, i.e. alcohols and acetone. Other species are proteolytic, some being ca- pable of attacking native and coagulated proteins with putrefaction or more complete pro- teolj'sis. Several species are active in the fi.xation of free nitrogen. Strictly anaerobic or anaerobic, aerotolerant. Catalase is lacking except in small amounts in certain aerotolerant forms. A few species are obligately thermophilic. Exotoxins are sometimes produced. Com- monly found in soil and in the intestinal tracts of man and other animals. The type species is Clostridium huiyricum Prazmowski.
- Revised by Prof. R. S. Spray, School of Medicine, West Virginia University, Morgan-
town, West Virginia, May, 1942. Further revision by Prof. L. S. McClung, Department of Bacteriology, Indiana University, Bloomington, Indiana, and Prof. Elizabeth McCoy, Department of Bacteriology, College of Agriculture, University of Wisconsin, Madison, Wisconsin, September, 1955.
