962 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



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, cen- 

 ters elevated, hollow on reverse side; 

 later a coherent membranous growth, 

 piled up, yellowish. 



Glycerol agar: Small, round, cream- 

 colored, glistening colonies, heavy tex- 

 ture, margins submerged; later, colonies 

 umbilicated, 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, 

 centrally depressed into medium. 



Potato agar: Poor growth, small, color- 

 less blister colonies, medium slightly 

 discolored. 



Dorset's egg medium: Round, flat, 

 colorless, 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, cen- 

 trally elevated, depressed at margin, re- 

 sembling limpets. 



Blood agar: Large drab heavily tex- 

 tured 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 : From the spleen in a case of 

 acholuric jaundice. 



Habitat : From human infections so 

 far as known. 



G7. Streptomyces hortonensis (Erik- 

 son) covib. nov. {Actinomyces horton 

 Erikson, Med. Res. Council Spec. Rept. 

 Ser. 203, 1935, 36.) Named for the 

 Horton War Hospital at Epsom, England 

 from which the culture was obtained. 

 Description from Erikson {loc. cit., 

 p. 22). 



Typical germination into very slow 

 growing unicellular mycelium composed 

 of long slender straight branching fila- 

 ments. Very sparse straight aerial my- 

 celium produced only once on potato. 

 Non-acid -fast. 



Gelatin : Round cream-colored colonies 

 on surface and a few mm below. No 

 liquefaction. 



Agar : Very slow growth, a few smooth 

 cream-colored coiled colonies in 19 days ; 

 after 2 months, liberal, irregular, convo- 

 luted growth. 



Glucose agar: Coiled and heaped up 

 cream-colored translucent masses; after 

 2 months, growth rounded, elevated, 

 ridged outwards from hollow center. 



Glycerol agar: Coiled, colorless, lus- 

 trous patches, isolated colony with cen- 

 tral depression. 



Serum agar : Poor growth, small amor- 

 phous cream-colored mass. 



laspissated serum: Intricately coiled 

 cream-colored growth. No liquefaction. 

 Broth : Flakes . 



Synthetic sucrose solution : Poor 

 growth, a few flakes. 



Synthetic glycerol solution: Delicate 

 white flocculi at base. 



Litmus milk: Green surface growth, 

 liquid hydrolyzed, partly clear purple; 

 later decolorized, brown. 



Potato agar : Colorless blister colonies 

 in one week ; dull green heaped and coiled 

 mass after 3 weeks ; medium becomes 

 slightly discolored. 



Potato plug: After 3 weeks, abundant, 

 colorless, umbilicated, round colonies, 

 some coiled in raised masses; later, liberal 

 olive-green growth, piled up, dense, 

 velvety gray-green aerial mycelium at 

 top of slant, small round fluffy white 

 colonies in liquid at base. 



