SPECIES OF NOCARDIA 139 



11. Nocardia paraffinae (Jensen) Waksman and Henrici. (Jensen, H., 

 Proc. Linnean Soc. N. S. Wales, 56, 1931, 362.) 



Mycelium: In agar media, the organism initially forms an extensive 

 mycelium of long, richly branching hyphae, 0.4-0.5 /x thick. After 5 to 6 

 days, at room temperature, numerous end branches swell to about double 

 thickness, become more refractive, exhibit fine incisions along their ex- 

 ternal contours, and divide into oval, spore-like elements, 0.8-1.0 by 1.2- 

 1.5 m- This process of division starts at the tips of the swollen branches and 

 proceeds basipetally until most of the hyphae appear divided. Primary 

 septa have not been seen in the hyphae. A similar process of division takes 

 place in liquid media, where also the filaments often fall into fragments of 

 variable length. The spore-like elements, but not the undivided filaments, 

 are markedly acid-fast. The aerial mycelium consists of rather short, 

 straight, not very much branched hyphae, 0.4-0.6 ju thick, which never 

 show any differentiation into spores. Erikson (loc. cit.) added the following 

 characteristics: Growth hard, firm, yellowish, with a certain amount of 

 white aerial mycelium on most nutrient agars. Because of the latter prop- 

 erty, this organism is said to approach the true Streptomyces types. Acid- 

 fastness is observed in certain stages, notably in the early stages of growth 

 and in the coccus forms. 



Nutrient agar: Slow but good growth. Vegetative mycelium superficial, 

 somewhat raised, ocher-yellow, hard, but with a loose, smeary surface. 

 Aerial mycelium scant, small white tufts. No pigment. 



Glucose agar: Fair growth. Vegetative mycelium flat, growing into me- 

 dium; pale ocher-yellow to orange, with raised outgrowths on the surface. 

 Growth of a crumbly consistency. Scant, white aerial mycelium. 



Potato: Fair growth. Vegetative mycelium granulated, first pale yellow, 

 later deep ocher-yellow to orange. Scant, white aerial mycelium. No pig- 

 ment. 



Gelatin: No liquef action. 



Milk : No coagulation or digestion. 



Starch: No hydrolysis. 



Cellulose: No decomposition. 



Nitrate: No reduction. 



Sucrose: No inversion. 



Sucrose agar: Very scant growth. Thin colorless veil, sometimes with a 

 trace of white aerial mycelium. 



Liquid media (milk, broth, synthetic solutions): Small, round granules 

 of various yellow to orange colors, firm but can be crushed into a ho- 

 mogeneous smear. In old broth cultures a thick, hard, orange to brownish 

 surface pellicle is formed. 



