SUMMARY 261 



Reaction in dextrose broth faintly acid, in lactose broth 

 alkalin or faintly acid. Gelatin slowly liquefied. Nitrates 

 reduced to nitrites or ammonia. 



Species 3. S. lutea Schroter. 



A saprophytic or semi-parasitic coccus, found most 

 commonly in earth, water, and air, frequently also on the 

 surfaces of the animal body. Occurs under favorable 

 conditions in packets. Generally decolorizes by Gram. 

 Good to abundant, yellow surface growth. Reaction in 

 dextrose broth faintly acid, in lactose broth alkalin or 

 faintly acid. Gelatin not liquefied. Nitrates not reduced. 



Genus VIII . Rhodococcus Winslow and Rogers. 



Saprophytes. Cells in groups or regular packets. Gen- 

 erally decolorize by Gram. Growth on agar abundant, 

 with formation of red pigment. Dextrose broth slightly 

 acid, lactose broth neutral. Gelatin rarely liquefied. 

 Nitrates generally reduced to nitrites, but not to ammonia. 



Species 1. R. roseus (Fliigge, Dyar) Winslow. 



A saprophytic coccus, found most commonly in earth, 

 water, and air. Occurs in pairs, groups, or packets. 

 Generally decolorizes by Gram. Abundant, red surface 

 growth. Reaction in dextrose broth faintly acid, in 

 lactose broth alkalin or faintly acid. Gelatin either not 

 liquefied or liquefied very slowly. Nitrates reduced to 

 nitrites, but not to ammonia. 



