Cultivation 



737 



From such anaerobic cultures the micro-organism can, after a few 

 generations, be made to grow upon the surface of solid media, where 

 it invariably forms rounded nodular, elevated masses. 



A B C 



Fig- 303- — Actinomycosis; glycerin-agar cultures: A, Discrete rounded 

 colonies after about ten days' incubation at 37°C.; B, limpet-shaped colonies 

 three and a half months old; C, lichen-like appearance frequently seen; the 

 growth is three and a half months old (Curtis). 



Blood-serum.^Upon blood-serum the nodular growths present 

 a yellowish or rust-red color, and are surrounded with a whitish down 



