Slender rods, 0.5 by 4 to 7 microns, fre- quently slightly curved, beaded and barred forms often occur. Non-motile. Acid-fast in cultures of 4 days or older, in younger cul- tures some organisms are not acid-fast. Not alcohol-fast. Gram-positive. Gelatin stab: Growth occurs along the line of inoculation. No liquefaction. Agar colonies: 0.5 to 1 mm in diameter, irregular, raised, moist and glistening. Glycerol agar: Spreading, raised, dry, pale pink to buff growth. Glycerol broth : A thin pellicle appears in 5 to 6 days, gradually becomes thicker and falls as a sediment. Dorset's egg medium: Raised, moist, pinkish growth after 10 days, later becom- ing salmon-colored. Loeffler's serum: Small, raised, convex, dry growth. Litmus milk: Alkaline. Glycerol potato: Raised, hemispherical, dry and granular growth. Indole not produced. Fructose, mannitol and trehalose are utilized; arabinose, sucrose, galactose and sorbitol not utilized (Gordon, Jour. Bact., 54, 1937, 617). Nitrates reduced by 1 strain but not by 2 strains tested (Aronson). Nitrates slightly reduced (Gordon). Nitrates not reduced (Bynoe). Temperature relations: Fails to survive 60° C. for 1 hour, fails to grow at 45° C. (Gordon) ; good growth at 25° C., no growth at 37° C. (Aronson); optimum for growth, 25° C., range, 10° to 35° C. (Bynoe). Range of pH, 6.6 to 7.8 (Aronson); opti- mum, between 7.3 and 8.0, range 5.0 to 11.0 (Bynoe). Pathogenicity: Experimentally produces generalized tuberculosis in snakes, frogs, lizards and fish but not pathogenic for guinea pigs, rabbits or fowls. Variation: According to Bynoe and Wyckoff (Amer. Rev. Tub., 29, 1934, 389), S and R forms may be distinguished by colony structure and individual cell ar- rangement. Source: Isolated from the lungs and livers of garter snakes (Thamnophis sirtalis). Habitat: Present as a parasite in the garter snake and possibly other cold- blooded vertebrates. 6. Mycobacterium platypoecilus Baker and Hagan, 1942. (Jour. Inf. Dis., 70, 1942, 248.) pla.ty.poe'ci.lus. M.L. mas.n. Platy- poecilus a genus of platyfishes. Rods resembling those of the tubercle bacillus; not usually pleomorphic. Strongly acid-fast. Glycerol egg medium: Primary growth on this medium only after 3 weeks of incuba- tion at 25° C. Smooth, moist colonies be- coming dry, wrinkled, grayish white and waxy with age. Cultures grown in the presence of light are deep orange in color. Glycerol phosphate agar: Growth of sub- cultures slow. Appearance same as on glycerol egg medium. Sohngen's medium: No growth. Temperature relations: Optimum, 25° C. No growth at 37° C. Source: Isolated from the organs of a small, tropical platyfish, Platypoecilus ma- culatus. Habitat: Found in skin ulcers, liver, spleen, gills and kidneys of diseased platy- fish. 7. Mycobacterium ulcerans MacCal- lum, 1950. (A new mycobacterial infection of man, MacCallum, Tolhurst, Buckle and Sissons, Jour. Path, and Bact., 60, 1948, 93; MacCallum, in Fenner, Med. Jour. Austral., 2, 1950, 817; also see Fenner and Leach, Austral. Jour. Exp. Biol, and Med. Sci., 30, 1952, 1; and Fenner, ibid., 11.) ul'ce.rans. L. part. adj. ulcerans making sore, causing to ulcerate. Description taken from MacCallum et al. {op. cit., 1948, 93). Rods, 0.2 by 1.5 to 3.0 microns from cul- tures, somewhat longer from tissues. Acid- fast and acid-alcohol-fast, frequently beaded. Egg yolk agar colonies: Primary cultures after 9 weeks are 2 to 3 mm in diameter, round, smooth, low convex, opaque white to pale cream-colored. Subcultures appear in 2 to 3 weeks, the colonies similar to those of the primary culture.
