90 ACTINOMYCETES 



Glucose agar: Growth restricted, gray, becoming red. 

 Potato: Growth wrinkled, cream-colored, turning yellowish. 

 Gelatin: Surface colonies small, cream-colored. Liquefaction slow. 

 Milk: Ring gray; coagulation; peptonization slow, becoming faintly alka- 

 line. 



Starch: Colonies restricted, circular, bluish violet. Hydrolysis positive. 



Glucose broth: Sediment fine, flaky, colorless. 



Nitrate: Reduction to nitrite. 



Temperature: Optimum 37°C. 



Antagonistic properties : Negative. 



Remarks: Soluble purple pigment formed. 



89. Streptomyces exfoliatus (Waksman and Curtis) Waksman and 

 Henrici. (Waksman, S. A., and Curtis, R. E., Soil Sci., 1, 1916, 116.) 



Aerial mycelium: Filaments slightly wavy with tendency to form spirals. 

 Conidia oval, 1.0-1.5 by 1.2-1.8 m- 



Synthetic agar: Growth smooth, glossy, colorless, becoming brown. Aerial 

 mycelium in white patches over surface. 



Nutrient agar: Growth only in depth of medium. 



Potato: Growth somewhat wrinkled, gray, becoming brown. 



Gelatin: Surface growth cream-colored. Liquefaction. 



Milk: Ring cream-colored; soft coagulation in 12 days; peptonization 

 slow. 



Starch: Growth restricted, gray becoming brown. Hydrolysis. 



Glucose broth: Colonies in depth small, grayish. 



Nitrate: Reduction to nitrite. 



Temperature: Optimum 37 °C. 



Antagonistic properties: Positive. 



Remarks: Brown, soluble pigment formed. 



90. Streptomyces gelaticus (Waksman) Waksman and Henrici. (Waks- 

 man, S. A., Soil Sci., 8, 1919, 165.) 



Aerial mycelium: Branching, with open spirals. 



Synthetic agar: Growth colorless, spreading, chiefly deep into the me- 

 dium. Aerial mycelium thin, white, turning grayish. 



Nutrient agar: Growth only on surface, wrinkled, cream-colored. 



Glucose agar: Growth abundant, spreading, white. 



Potato: Growth abundant, much-wrinkled, greenish, becoming black with 

 yellowish margin. 



^Gelatin: Liquefaction; sediment flaky, cream-colored. 

 fjjjMilk: Ring pinkish; coagulation; peptonization with distinctly alkaline 

 reaction. 



