Glucose-peptone medium: Numerous col- onies covering surface. Soluble brownish pigment weakly produced. Milk: Slow growth. Aerial mycelium white. No soluble pigment. At 25° C, not coagulated; at 37° C, coagulated after 20 days. Not peptonized. No change in reac- tion. Nitrites produced from nitrates. Proteolysis: No action on coagulated serum. Pathogenicity: Pathogenic for guinea pigs and rabbits. Not pathogenic for dogs after laboratory growth. Source : Isolated from cases of dog septi- cemia (thoracic, abdominal and brain le- sions). Habitat: Found in dogs, guinea pigs and rabbits so far as known. 143. Streptomyces upcottii (Erikson, 1935) Waksman and Henrici, 1948. (A new pathogenic form of Streptothrix, Gibson, Jour. Path, and Bact., 23, 1920, 357; Actino- myces upcottii Erikson, Med. Res. Council Spec. Rept. Ser. 203, 1935, 36; Waksman and Henrici, in Manual, 6th ed., 1948, 961.) up.cot'ti.i. M.L. gen. noun upcottii of Upcott; named for Dr. Harold Upcott, the surgeon who first secured this organism. Description taken from Erikson (op. cit., 1935, 22). Vegetative growth: Filaments charac- teristically long, straight, much interwoven and ramified; typical unicellular mycelium, usually forming medium to large heavy cartilaginous colonies. Aerial mycelium: A very slight transient aerial mycelium appeared on one agar slope, but this has not been repeated on any slide microculture on any medium. Slightly acid- fast. Gelatin: Abundant flocculent growth along streak, round cream-colored colonies on surface. Partly liquefied in 14 days; complete liquefaction in 2 months. Agar: Smooth, shining, round, cream- colored colonies, margin submerged, scant white aerial mycelium in one week; colonies large (up to 10 mm in diameter), centers elevated, greenish tinge, very sparse aerial mycelium in two weeks ; the aerial mycelium disappears and large radial grooves appear in most colonies in 3 weeks. Glucose agar: Smooth, round, cream- colored colonies, margin depressed, centers elevated, hollow on reverse side; later a coherent membranous growth, piled up, yellowish. Glycerol agar: Small, round, cream- colored, glistening colonies, heavy texture, margins submerged; later, colonies umbili- cated, tending to be piled up; after 6 weeks, growth very much convoluted and raised, broad submerged margin, slightly reddish medium. Coon's agar: Small, radiating, white colonies, growth mostly submerged. Ca-agar: Small, colorless membranous growth with undulating margin; later, cen- trally depressed into medium. Potato agar: Poor growth, small, color- less blister colonies, medium slightly dis- colored. Dorset's egg medium: Round, flat, color- less, scale-like colonies, some marked by concentric rings and slightly hollowed in center; growth becomes yellow-brown. Serum agar: Large colonies (3 to 4 mm in diameter), colorless, granular, centrally elevated, depressed at margin, resembling limpets. Blood agar: Large drab heavily textured colonies; no aerial mycelium; no hemolysis. Broth: Large coherent mass composed of fluffy colonies. Synthetic sucrose solution: Fair growth, minute white colonies. Carrot plug: Colorless, spreading, moist, wrinkled growth in six weeks; later a dull greenish brown, moist, very much wrinkled and depressed skin. Source : Isolated from the spleen in a case of acholuric jaundice. Habitat: Unknown. 144. Streptomyces hortonensis (Erik- son, 1935) Waksman and Henrici, 1948. {Actinomyces horton (sic) Erikson, Med. Res. Council Spec. Rept. Ser. 203, 1935, 36; Waksman and Henrici, in Manual, 6th ed., 1948, 962.) hor.to.nen'sis. M.L. adj. hortonensis per-
