CULTIVATION OF ACTINOMYCES 



327 



enlarge and form rounded projections of a reddish-yellow tint 

 and somewhat transparent appearance, like drops of amber. 

 The growths tend to remain separate, and even when they 

 become confluent, the nodular character is maintained. 

 They have a tough consistence, being with difficulty broken up, 

 and adhere firmly to the surface of the agar. Older growths 

 often show on the surface a sort of corrugated aspect, and may 

 sometimes present the appearance of having been dusted with a 

 brownish-yellow powder (Fig. 93). 



In the cultures at an early stage the growth is composed 

 of branching filaments, 

 which stain uniformly 

 (Fig. 94), but later some 

 of the superficial fila- 

 ments may show seg- 

 mentation into gonidia. 

 Slight bulbous thicken- 

 ings may be seen at 

 the end of some of the 

 filaments, but true clubs 

 have not been observed. 



On gelatin the same 

 tendency to grow in 

 little spherical masses is 

 seen, and the medium 

 becomes very slowly 

 liquefied. When this 

 occurs the liquefied por- 

 tion has a brownish 

 colour and somewhat 

 syrupy consistence, and 



the growths may be seen at the bottom, as little balls, from 

 the surface of which filaments radiate. 



Inoculation experiments have, on the whole, given negative 

 results, and it has become doubtful whether this organism really 

 plays a causal r61e in actinomycosis. 



(2) Streptothrix actinomyces (Israel and , Wolff). — The 

 organism obtained in culture by Wolff and Israel (vide 

 infra) is probably the same as the one which was later 

 described in detail by J. H. Wright, who obtained it in pure 

 condition from fifteen different cases of the disease. It differs 

 markedly from Bostrom's organism in being almost a strict 

 anaerobe and in ceasing to grow at a temperature a little below 

 that of the body. Under ordinary aerobic conditions either no 



Fig. 94. — Actinomyces, from a culture on 

 glycerin agar, showing the branching of the 

 filaments. See also Plate III., Fig. 10. 

 Stained with fuchsin. x 1000. 



