II. Glj^cerol fermented with the production of no visible gas. Gelatin liquefied. 2. Aerobacter cloacae. 1. Aerobacter aerogenes (Kruse, 1896) Beijerinck, 1900. (Bakterium lactis aerogenes (sic) Escherich, Fortschr. d. Med., 3, 1885, 520; Bacillus aerogenes Kruse, in Fliigge, Die Mikroorganismen, 2, 1896, 340; not Bacillus aerogenes Miller, Deutsche rriied. Wochnschr., 1£, 1886, 119; Bacterium aerogenes Chester, Ann. Rept. Del. Col. Agr. Exp. Sta., 9, 1897, 53; not Bacterium aerogenes Miller, op. cit., 1886, 119; Beije- rinck, Arch, neerl. d. sci. exact, et nat., 4, 1900, 1.) a.e.ro'ge.nes. Or. mas.n. aer air, gas; Gr. V. gennaio to produce; M.L. adj. aerogenes gas-producing. Rods, 0.5 to 0.8 by 1.0 to 2.0 microns, occurring singly. Frequently encapsulated. Usually non-motile. Gram-negative. Gelatin colonies: Thick, porcelain-white, opaque, moist, smooth, entire. Gelatin stab: Thick, spreading, white, opaque surface growth. No liquefaction. Agar colonies: Thick, white, raised, moist, smooth, entire; more convex than those of Escherichia coli and often mucoid. Agar slant: Abundant, thick, white, moist, glistening, spreading growth. Broth: Turbid; pellicle; abundant sedi- ment. Litmus milk: Acid with coagulation; no peptonization. Potato: Thick, yellowish white to yel- lowish brown, spreading growth with nodular outgrowths over the surface. Indole may or may not be produced (Ford, Studies from the Royal Victoria Hospital, Montreal, 1, 1901-1903, 16; Bardsley, Jour, of Hyg. (Eng.), 34, 1934, 38; Wilson, IVIed. Res. Council, London, Spec. Rept. Ser. 206, 1935, 161). Hydrogen sulfide not produced in peptone iron agar (Levine, Epstein and Vaughn, Amer. Jour. Pub. Health, 24, 1934, 505; Tittsler and Sandholzer, Amer. Jour. Pub. Health, 27, 1937, 1240). More sensitive indicators give positive tests for hydrogen sulfide (Hunter and Weiss, Jour. Bact., 35, 1938,20). Acid and gas from glucose, fructose, galactose, arabinose, lactose, maltose, rafiinose, cellobiose, salicin, esculin, starch, dextrin, glycerol, mannitol, sorbitol and inositol; a-methyl-glucoside is usually fermented (Koser and Saunders, Jour. Bact., 24, 1932, 267). Sucrose, inulin, dulcitol and adonitol may or may not be fermented. Protopectin not fermented. Variable fer- mentation of sucrose and mannitol (Sher- man and Wing, Jour. Bact., 33, 1937, 315). Gas ratio : Two or more volumes of carbon dioxide to one of hydrogen are produced from glucose (Harden and Walpole, Proc. Roy. Soc, Series B, 77, 1905, 399; Rogers, Clark and Davis, Jour. Inf. Dis., 14, 1914, 411). Trimethylenegh'col not produced from glycerol by anaerobic fermentation (Braak, Onderzoekingen over Vergisting van Glyc- erine. Thesis, Delft, 1928, 212; Werkman and Gillen, Jour. Bact., 23, 1932, 167). Methyl red test negative (Clark and Lubs, Jour. Inf. Dis., 17, 1915, 160); Voges- Proskauer test positive (Durham, Jour. Exp. Med., 5, 1901, 373); inverse correlation between methyl red and Voges-Proskauer tests (Levine, Jour. Bact., 1, 1916, 153). Citric acid and salts of citric acid may be utilized as sole sources of carbon (Koser, Jour. Bact., 8, 1923, 493). Uric acid may be utilized as a sole source of nitrogen (Koser, Jour. Inf. Dis., 23, 1918, 377). Sodium hippurate is hydrolyzed (Hajna and Damon, Amer. Jour. Hyg., 19, 1934, 545) . Nitrites produced from nitrates. - Catalase-positive. Aerobic, facultativelv anaerobic. ter for differentiating species due to occasional loss of gelatin-liquefying ability. This was confirmed by Levine (Amer. Jour. Pub. Health, 7, 1917, 784), who reports that the two char- acters do not correlate perfectly. Griffin and Stuart (Jour. Bact., 40, 1940, 93 ff.) find a similar correlation of characters but feel that, because these characters do not correlate perfectly, it would be better to combine the two species into a single species.
