chmmogenes Jensen, Proc. Linnean Soc. New So. Wales, 56, 1931, 79 and 363; Waksman and Henrici, in Manual, 6th ed., 1948, 897.) po.ly.chrom.o'ge.nes. Gr. adj. pobj many; Gr. noun chromus color; Gr.v. gen- naeo to produce; M.L.adj. polychromogenes producing many colors. Description taken from Jensen (op. cit., 1931). Long, wavy filaments, 0.4 to 0.5 by 70 to 100 microns, extensively branched but with- out septa. Older cultures consist entirely of rods 4 to 10 microns in length, frequently in V, Y or smaller forms. Still older cultures consist of shorter rods and coccoid forms. Gram-positive, frequently showing bands and granules. Gelatin stab: Thin, yellowish growth along the stab with thin, radiating fila- ments. Surface growth flat, wrinkled, red. No liquefaction. Nutrient agar: Scant, orange-red growth. Glucose agar: After 3 to 4 days, raised, flat, glistening, rose-colored growth. After 1 to 3 weeks, becoming folded and coral-red. Glucose broth: After 3 to 4 days, turbid; after 2 to 3 weeks an orange, flaky, sediment. No surface growth. Milk: Growth starts as small orange- colored surface granules. After 1 to 2 weeks a thick, soft, orange-colored sediment forms. Optimum temperature, between 22° and 25° C. Distinctive characters: Differs from No- cardia corallina in the formation of very long filaments and in filiform growth in gelatin stabs. Source : Isolated from the blood of a horse and from soil in France and Australia. Habitat: Soil. 4. Nocardia opaca (den Dooren de Jong, 1927) Waksman and Henrici, 1948. (Mycobacterium opacum den Dooren de Jong, Cent. f. Bakt., II Abt., 71, 1927, 216; Proactinomyces opacus Jensen, Proc. Linn. Soc. New So. Wales, 57, 1932, 369; Waksman and Henrici, in Manual, 6th ed., 1948, 897.) o.pa'ca. L.adj. opacus shaded, dark. Description taken from Gray and Thorn- ton (Cent. f. Bakt., II Abt., 73, 1928, 86), Bynoe (Thesis, McGill University, Mon- treal, 1931), Jensen (op. cit., 1932, 369) and Erikson (Jour. Gen. Microbiol., 3, 1949, 363). Long, curved, irregular and branching filaments or rods, 0.8 to 1.0 by 2 to 16 mi- crons, or occasionally longer. Few chains or clumps are formed. In older cultures shorter rods or cocci are generally formed. Readily stained. Not acid-fast. Acid-fast cell ele- ments predominate during periods of maxi- mum growth and free air supply (Erikson). Gram-positive. Gelatin colonies: Round, convex, whitish, smooth, shining, edges slightly arborescent. Deep colonies: Burrs, with slightly irreg- ular processes. Gelatin stab: Convex, whitish, smooth, resinous, filiform, erose. Nutrient agar: Soft cream to pink growth (Erikson). Synthetic agar: Growth colorless and thin, producing an initial mycelium, the hyphae dividing rapidly into short rods; addition of 0.01 per cent MnS04 stimulates production of pale pink pigment (Erikson). Broth: Turbid with broken white scum or clear with granular suspension. Dorset's egg medium: Spreading, smooth, moist, salmon-colored growth. Loefiler's medium: Scant, smooth, moist, light buff-colored growth. Glycerol potato: Dry, rough, crumpled, pink to buff -colored growth. Litmus milk: Grayish pellicle; slightly alkaline. No acid from sucrose, lactose, maltose or glucose. Phenol and naphthalene are utilized as sources of energy. Nitrites produced from nitrates. Optimum temperature, 30° C. Optimum pH, between 6.8 and 7.3. Distinctive characters: Differs from No- cardia corallina and Nocardia polychromo- genes in that the cells are much longer than those of the former and much shorter than those of the latter. Grows in smooth convex surface colonies and burr-like deep colonies. Source: Twenty-four strains were isolated from soils in Great Britain.
