ACTINOMYCES CHROMOGENES. 453 



non Cohn. Cladothrix odorifera RuUmann (C. B. xvii, 

 884, and C. B. L. ii, 701). "Brauner Hesse." 



Microscopic Appearance. — True branching threads, 

 often with perceptible separation into longer and shorter 

 rods (67, X). There is no motility, but RuUmann has seen 

 motion in the youngest stages. 



On the air threads (see below), by continuous trans- 

 verse division, short roundish members are formed (true 

 conidia), which very readily fall off, and, upon germina- 

 tion, form new branching mycelium. 



^=» 



Fig. 23. — Actinomyces chromogenes. Gasperini. (Upper side of a 

 bouillon pellicle magnified about 700 times. ) 



Staining Properties. — With all anilin dyes and by 

 Gram's method. 



Relation to Oxygen. — Grows better aerobically. 



Requirements as Regards Temperature and Nutri- 

 ent Media. — Thrives upon all ordinary nutrient media at 

 room and incubator temperature, more rapidly at the 

 latter. 



Gelatin Plate. — (a) Natural size: At first the colonies 

 are brownish, round, slightly elevated, tough, dull, and 

 begin first in the center, rarely at the periphery, to take 

 on a whitish, chalky condition. Hereupon are formed 

 concentric, wide, white rings; the drier (thinner) the nu- 

 trient medium, the more rapidly there occurs a more or 

 less complete overgrowth of the colony, with white air 

 hyphse, and therewith a chalky appearance. The gelatin 

 near the colony is colored dark brown and is slowly lique- 



