branching mycelium. Black pigment slowly produced. Litmus milk: Unchanged. Potato: Barnacle-like, brownish, spread- ing growth; no aerial mycelium. Medium brownish around growth. Indole not produced. No acid from glucose, lactose, maltose, mannitol, sucrose or dulcitol. Good growth at 25° C. Slow growth at 37° C. Distinctive character: Produces an anti- biotic substance (proactinomycin) upon synthetic and organic media which is pri- marily active against various Gram-positive bacteria. Source: Isolated as an air contaminant at Oxford, England. Habitat: Unknown. 42. Nocardia fordii (Erikson, 1935) Waksman, 1953. (Actinomyces fordii Erik- son, Med. Res. Council Spec. Rept. Ser. 203, 1935, 15 and 36 ; Streptomyces fordii Waksman and Henrici, in Manual, 6th ed., 1948, 958; Waksman, in Waksman and Lechevalier, Actinomycetes and Their Antibiotics, Bal- timore, 1953, 159.) for'di.i. M.L. gen. noun fordii of Ford; presumably named for the surgeon who first secured the culture. Filaments of medium length, no spirals or markedly wavy branches. Short, straight, sparse aerial mycelium. Small ovoid conidia on potato agar and starch agar. Gelatin : No visible growth, slight soften- ing in 20 daj^s; half-liquefied after 40 days. Agar: Small, creamy golden, ring-shaped colonies and heaped-up patches, becoming golden brown in color and convoluted. Glycerol agar: Extensive, golden brown, convoluted, thin layer. Serum agar: Golden brown, ring-shaped and coiled smooth colonies; no liquefaction. Ca-agar: Yellow, scale-like, closely ad- herent colonies; scattered white aerial my- celium. Blood agar: Innumerable, small, yellow- ish, ring-shaped colonies; no hemolysis. Broth: Few flakes at first; later abundant, coherent, puffball growth. Synthetic sucrose solution: Moderate sediment of minute round white colonies. Synthetic glycerol solution: Light white fluffy colonies, minute and in clusters. Inspissated serum: Innumerable, color- less, pinpoint colonies; scant white aerial mycelium; after 15 d&ys colonies large, hollow on reverse side; margin depressed; no liquefaction. Dorset's egg medium: Minute, cream- colored, elevated colonies, becoming golden brown, raised, convoluted. Milk: Coagulated; brownish surface ring. Litmus milk: No change in reaction. Potato plug: Yellowish growth in thin line, terminal portion tending to be piled up; scant white aerial mycelium at top of slant; after 12 days, growth abundant, golden brown, confluent, partly honey- combed, partly piled up. Starch not hydrolyzed. Tyrosine agar: Reaction negative. Source: Isolated from a human spleen in a case of acholuric jaundice. Habitat: Unknown. 43. Nocardia kuroishi Uesaka, 1952. (Jour. Antibiotics (Japanese), 5, 1952, 75.) ku.ro. i'shi. Etymology Japanese, mean- ing uncertain. Mycelium gives a weak acid-fast reaction, but the separated cells, 0.8 by 1.3 microns, are not acid-fast. Aerial mycelium: Abundant, branching hyphae slightly curved at first, later turning around each other; cells refractive. Gran- ules soon become visible. Gelatin: Yellowish brown growth sinking into medium. No aerial mycelium. Yellowish brown, soluble pigment. No liquefaction. Synthetic glycerol agar: Thin, pale yellow growth, partly covered with punctiform, white aerial mycelia. Yellow pigment. Agar: Wrinkled, grayish yellow colonies. No aerial mycelium. Faint, grayish brown, soluble pigment. Glucose agar: Abundant growth, at first yellowish brown then reddish brown. Scant white aerial mycelium at margin of colonies. Red to wine-colored, soluble pigment. Synthetic solution: White, minute colonies on surface. Medium becomes brown. Glucose broth: Red colonies, forming a
