178 



THE ACTINOMYCETES, Vol. II 



Glucose-asparagine agar: Growth light 

 orange; raised center, hyaline margin. Aerial 

 mycelium light drab. 



Nutrient agar: Growth restricted, gray. 

 No aerial mycelium. Soluble pigment deep 

 brown. 



Starch agar: Growth thin, transparent, 



spreading. Aerial mycelium buff-colored. 

 Good hydrolysis. 



Potato: Growth abundant, wrinkled, 

 brown, becoming black. Aerial mycelium 

 white to ash-gray. Soluble pigment black. 



Gelatin: Surface growth fair, cream-col- 

 ored, becoming brown. Aerial mycelium 



Figure 32. Sporophores of S. aureus, X 30,000 (Courtesy of E. Baldacci, University of Milan, Italy). 



