A. Limited proteolytic action in gelatin, milk, coagulated egg-albumin or fibrin.
1. Vegetative growth white.
a1. No soluble pigment in organic media.
141. Streptomyces listeri.
a2. Soluble pigment in organic media brown to brown-red.
142. Streptomyces galtieri.
2. Vegetative growth cream-colored; aerial mycelium scant, white.
143. Streptomyces upcotlii.
3. Growth very limited on various media, except on potato plug; no liquefaction of gelatin.
144. Streptomyces hortonensis.
B. Strong proteolyetic action in gelatin and milk.
1. Growth on potato plug moist, membranous.
a1 Pigment deep brown.
145. Streptomyces beddardii.
a2. Pigment faint brown.
146. Streptomyces kimberi.
2. Growth on potato plug abiuidant, becoming black; aerial mycelium white-gray; plug discolored.
147. Streptomyces somaliensis.
3. Growth on some media pink.
148. Streptomyces panjae.
4. Aerial mycelium on most media profuse, white; spiral formation.
149. Streptomyces willmorei.
V. No aerial mycelium.
150. Sterile (non-conidia-forming) species.
1. Streptomyces albus (Rossi-Doria, 1891, emend. Krainsky, 1914) Waksman and Henrici, 1943. (Streptotrix (sic) alba Rossi- Doria, Ann. d'Ist. d'Ig. sper. d. Univ. di Roma, 1, 1891, 399; Actinomyces albus Krainsky, Cent. f. Bakt., II Abt., 41, 1914, 662; Waksman and Henrici, Jour. Bact., 46, 1943, 339.)
al'bus. L. adj. albus white.
The description of this species by Rossi- Doria is incomplete. The characters given below are taken from Krainsky (op. cit., 1914, 662) with some supplementary infor- mation from later authors. Other descrip- tions which may vary from this in certain details are given by Waksman and Curtis (Soil Sci., 1, 1916, 117), Bergey et al. (Man- ual, 1st ed., 1923, 367), Duché (Les actino- mycesdugroupe albus, Paris, 1934, 257) and Baldacci (Mycopathologia, 2, 1940, 156).
Vegetative growth: Hyphae branched, 1 micron in diameter.
Aerial mycelium: Abundant, white. Hyphae 1.3 to 1.7 microns in diameter with ellipsoidal spores (1 micron long) in coiled chains on lateral branches of the aeria hyphae.
Gelatin: Rapid liquefaction. Gray colonies. No soluble pigment.
Agar: No aerial mycelium, but a chalky white deposit forms on old colonies.
Ca-malate agar: Colonies of medium size; he center only is covered with a white aerial mycelium.
Starch agar: White aerial mycelium covering the whole surface.
Glucose agar: Gray aerial mycelium becoming brownish.
Broth: Flaky growth on bottom with cultures. White aerial mycelium.
Milk: Rapidly peptonized after coagulation. Reaction becomes alkaline (Duché). Cream-coloured surface ring. White arial mycelium.
Potato: White aerial mycelium. Growth folded, cream-colored.
Carrots and other vegetables: Excellent growth (Duché).
No hydrolysis of starch in some cultures; rapid hydrolysis in others.
