Indole not produced. Hj^drogen sulfide produced in broth and in agar by some cultures but not by others. No acid or gas from arabinose, dextrin, glucose, dulcitol, galactose, inulin, lactose, fructose, maltose, mannitol, rafiinose, rham- nose, salicin, sorbitol, sucrose or xylose. Ethyl, propyl, butyl and amyl alcohols oxidized largely to corresponding acids; hexyl and heptyl alcohols attacked much less actively. Nitrites produced from nitrates. Methyl red test negative. Acetjdmethylcarbinol not produced. Natural fats not hydrolyzed. Catalase rapidly produced in or on various media. Aerobic. Temperature relations: Optimum, about 21° C. Growth at 8° and 37° C. but not at 45° C. Heat resistance low, cultures being killed at 62.8° C. in a few minutes. Growth in the pH range 6.0 to 9.8; no growth at pH 5.0 or below. Salt tolerant, cultures growing readily in a concentration of 15 per cent salt in broth or skim milk, with certain cultures appar- ently capable of growing somewhat in much higher concentrations. Relationships to other species: Closely re- lated to or identical with Bacterium erythro- genes Lehmann and Neumann. Source : Originally isolated by Wolff from the surface flora of various soft cheeses. Habitat: Widely distributed in and es- pecially on the surface of dairy products including blue, brick, camembert, lim- burger, oka and cheddar cheeses, butter, milk and cream. Also found in various feeds including grains, silage, green plants, hay and straw, and in water, soil, manure and air. 2. Brevibacterium erythrogenes (Leh- mann and Neumann, 1896) Breed, 1953. (Bacterium lactis erythrogenes Grotenfelt, Fortschr. d. Med., 7, 1889, 41; Bacterium erythrogenes Lehmann and Neumann, Bakt. Diag., 1 Aufl., 3, 1896, 253; Breed, Riassunti delle Comunicazioni, VI Congresso In- ternaz. di Microbiol., Roma, 1, 1953, 13; also see Atti del VI Congresso Internaz. d Microbiol., Roma, /, 1955, 13.) e.ryth.ro'ge.nes. Gr. adj. erythrus red; Gr. v. gennaio to produce; M.L. adj. erythro- genes producing a red (color). Rods, 0.3 to 0.5 by 1.0 to 1.4 microns, in broth often up to 4.3 microns long, occurring singly and having rounded ends. Non-mo- tile. Stain with the usual aniline dyes. Gram-positive (Lehmann and Neumann, op. cit., 1896, 253). Gelatin colonies: Small, circular, graj'ish, becoming yellow, sinking into the medium. Crateriform liquefaction. Yellow sediment. Medium becomes rose-colored. Gelatin stab: Surface growth a whitish, later yellow, circular, thin laj'er. Weak growth in stab. Slow liquefaction at the surface, the liquid becoming red with a yellow sediment. The solid portion assumes a weak rose color. Agar stab: Moist, fairly luxuriant, yellow growth, the medium assuming a rose to wine color. Broth: Turbid, yellow. Pellicle (Fuller and Johnson, Jour. Exp. Med., 4, 1899, 609). Litmus milk: Acid. Slow coagulation, hav- ing a clear fluid which becomes blood-red in color. Reaction becomes alkaline. Sterile milk: Casein slowly precipitated, later peptonized. Reaction neutral or alka- line. A stratum of blood-red serum is seen above the precipitated casein and above this is a yellowish white layer of cream. Produces an intensive sweet odor that be- comes disagreeable. Potato: Growth rapid, spreading, grayish, later yellow. On incubation a deep golden yellow color develops after 6 to 8 days. A darkening of the medium occurs around the culture but soon disappears; later the whole potato becomes a weak j^ellowish red. Indole not produced (Fuller and Johnson, loc. cit.). Indole produced (Chester, Manual Determ. Bact., 1901, 174). Slight hydrogen sulfide production (Mat- zuschita, Bakt. Diagnostik, 1902, 220). Blood serum: Liquefied (Fuller and John- son, op. cit., 1899, 609). Not liquefied (Hef- feran. Cent. f. Bakt., II Abt., //, 1903, 457). No gas from carbohydrates. Nitrites produced from nitrates. Red pigment insoluble in water, alcohol,
