sca'bi.es. L. noun scabies scab. Vegetative growth: Folded, compact yellowish to yellow-brown; soluble, brown pigment. Aerial mycelium: White, cottony or vel- vety; wavy or slightly curved hyphae show a few spirals. Spores cylindrical, 0.8 to 1.0 by 1.2 to 1.5 microns. Gelatin stab: Cream-colored surface growth, becoming brown. Slow liquefac- tion. Yellowish soluble pigment. Agar: Circular, entire colonies, smooth, becoming raised, lichenoid, wrinkled, white to straw-colored, opalescent to opaque. No aerial mycelium. Deep golden brown soluble pigment. Synthetic agar : Abundant, cream-colored, wrinkled, raised growth. Aerial mycelium white, scarce. Starch agar: Thin, transparent, spreading growth. Glucose agar: Restricted, folded, cream- colored, entire growth. Glucose broth: Ring in form of small colonies, settling to the bottom. Litmus milk: Brown ring with greenish tinge; coagulated; peptonized with alka- line reaction. Potato: Gray, opalescent growth, be- coming black, wrinkled. Brown plug. Brown soluble pigment formed. Starch is hydrolyzed. Strong tyrosinase reaction. Nitrites produced from nitrates. Aerobic. Optimum temperature, 37° C. Antagonistic properties: Certain strains give positive effects, others negative. Comments: The potato scab organism, like other acid-fast organisms, can be se- lectively impregnated with carbol-auramin and when exposed to ultraviolet radiation fluoresces bright yellow. This technic con- firms Lutman's conclusion that the hyphae are intercellular and grow within the mid- dle lamellae (Richards, Stain Tech., 18, 1943, 91-94). Relationships to other species: Sfrepto- myces clavifer, Streptoinyces spiralis, Sirepto- myces carnosus, Streptoinyces sampsonii and many other species or strains are closely related to this organism. Source: Isolated from potato scab le- sions. Habitat: Cause of potato scab; found in soil. 130. Streptoinyces tenuis (Millard and Burr, 1926) Waksman, 1953. {Actinomyces tenuis Millard and Burr, Ann. Appl. Biol., 18, 1926, 601; Waksman, in Waksman and Lechevalier, Actinomycetes and Their Antibiotics, Baltimore, 1953, HI.) te'nu.is. L. adj. tenuis slender. Aerial mycelium: Irregularly branched. Spores cylindrical, 0.82 by 0.87 micron. Gelatin: Pale gray growth covered with scant, white aerial mycelium. Soluble yel- low pigment. Rapid liquefaction. Synthetic sucrose agar: Growth pene- trates deep into substratum. Thin, fiat, yellowish drab surface growth. Aerial my- celium deep olive-buff. Soluble, pale orange- yellow pigment. Synthetic glucose agar: Thin, flat growth covered by olive-buff aerial mycelium. Sol- uble green pigment. Potato agar: Wrinkled, grayish grow^th. Aerial mycelium white to vinaceous-fawn- colored. Soluble, golden brown pigment. Glycerol synthetic solution: White, flak}- growth mostly at bottom. Aerial mycelium scant, olive-buff. Glucose broth: Whitish surface and bot- tom growth. Aerial mycelium abundant, w^rinkled, olive-buff. Soluble, golden brown pigment. Milk: Good growth covered with white aerial mycelium. Coagulated, followed by incomplete peptonization. Potato: Good growth covered with deep olive-buff aerial mycelium. Soluble, gray to olive to black pigment. Starch is hydrolyzed. Tyrosinase reaction: Negative. Nitrites not produced from nitrates. Source: Isolated from medium-sized, ruptured potato scab. Habitat: Found in potatoes so far as known. 131. Streptoniyces niarginatus (Mil- lard and Burr, 1926) Waksman, 1953. (Ac- tinomyces marginatus Millard and Burr,
