after incubation for 5 days at 28° C. on glycerol agar from 10 to 80 per cent. Gelatin: Usually no hydrolysis by Fra- zier method. Bennett's and soil extract agar colonies: Dense with smooth edges, dense with fringe of filaments, or filamentous. Filaments fragmenting into short rods. Glycerol agar slants: Growth at 2 to 3 days usually, rough, good, spreading, finely wrinkled, creamy white; at 14 days, abun- dant, spreading, finely wrinkled, waxy, cream-j'ellow to orange. Growth of cultures in smooth stage abundant, glistening, butyrous and sometimes nodular. Milk agar plate: No hydrolysis of casein. Acid from glucose, rhamnose, xylose, arabinose, sorbitol, inositol, mannose, man- nitol, trehalose and galactose (with am- moniacal nitrogen); usually from dulcitol. No acid from lactose and usually none from raffinose. Acid not produced from maltose by a majority of the cultures. Starch is hydrolyzed. Citrate, succinate and malate used as sole sources of carbon. Tyrosine not decomposed (Gordon and Smith, Jour. Bact., 69, 1955, 504). Benzoate utilized (Gordon and Smith, loc. cit.). Oxalate is decomposed by strains isolated from the intestines of earthworms (Kham- bata and Bhat, Jour. Bact., 69, 1955, 227). Khambata and Bhat identified their strains as Mycobacterium lacticola Lehmann and Neumann; however, an earlier study by Gordon and Smith (op. cit.., 1953, 44) has shown that M. lacticola is identical with M. smegmatis Lehmann and Neumann, the latter name having priority. Nitrites usually produced from nitrates. Temperature relations: Growth at 28° to 45° C. inclusive; scant, if any, at 50° C.; none at 52° C. Does not survive 60° C. for 4 hours. Salt tolerance: Usually growth in glycerol broth containing 5 per cent NaCl; usually none in 7 per cent. Source: Isolated from smegma. Habitat: Widely distributed in soil, dust and water. 3. Mycobacterium fortuitum Cruz, 1938. (Strains of Mycobacterium from cows 18, 19, 70 and 75, Minett, Jour. Comp. Path, and Ther., 45, 1932, 317; Cruz, Acta Med. Rio de Janeiro, 1, 1938, 298; Mycobacterium giae Darzins, Arquiv. Inst. Brasil. Invest. Tuberc, 9, 1950, 29; Mycobacterium minetti Penso, Castelnuovo, Gaudiano, Princivalle, Vella and Zampieri, Rend. dell'Istituto Superiore di Sanita, 15, 1952, 491.) for. tu'i. turn. L. adj. fortuitus casual, ac- cidental. Description taken from Cruz (op. cit., 1938, 298), Penso et al. (op. cit., 1952, 491) and Gordon and Smith (Jour. Bact., 69, 1955, 502). Rods, 1.0 to 3.0 microns in length after cultivation for 72 hours on glycerol agar at 28° C, the largest number from 2.0 to 2.2 microns in length. Coccoid and short forms, to long, slender rods, occasionally beaded or swollen with an ovoid, non-acid-fast body at one end. In pus, long and filamentous forms with definite branching (Penso et al.). Acid-fastness after incubation for 5 days at 28° C. on glycerol agar 10 to 100 per cent. In the majority of cultures, 70 to 100 per cent of cells were acid-fast. Non-motile. Gram-positive. Gelatin: No hydrolysis by Frazier method (Gordon and Smith). Gelatin stab: Heavy growth on surface and along stab. No liquefaction. Agar colonies : After 3 or 4 days of incuba- tion, dense colonies with smooth edges, dense colonies fringed with short filaments and/or filamentous colonies. On further incubation the filaments usually fragment into short rods (Gordon and Smith). Glycerol agar: Growth at 2 to 3 days at 28° C. scant to fair, soft and butyrous or waxy and nodular, off-white to cream- colored; at 14 days, abundant, spreading, butyrous and glistening or dull, rough and waxy, often very nodular, off-white to cream to beige in color (Gordon and Smith). Yeast extract agar: Growth moderate to heavy, spreading, butyrous or dry and waxy, usually nodular, sometimes finely wrinkled, off-white to cream to beige (Gor- don and Smith). Glucose asparagine agar : At 2 weeks, mod- erate, spreading, soft, and glistening or dull
