450 ACTINOMYCETES. 



distinct partition walls, 1 but many threads show a frag- 

 mentation into short, square ("cocci-like") segments, 

 which (according to Eppinger), by opening of the thread 

 membrane, may become free at the end (not observed by 

 us). The branching, as represented by Eppinger, and as 

 always seen by ourselves, is true branching, although he 

 described it as false. 



Spontaneous Motility. — The shorter threads exhibit a 

 sluggish, and the shortest threads and spherical forms a 

 very active motion (Eppinger). We have observed no 

 motility. 



Staining Properties. — Stain with all the anilin dyes 



Fig. 22. — Oospora asteroides Sauv. and Rad. (after Eppinger). 



and by Gram's method. According to Berestnew (Z. H. 

 xxix, 94), they also stain by Ziehl's method. 



Requirements as Regards Nutrient Media and Temperature. — 

 Grows best at 37° and upon all ordinary nutrient media, but most 

 luxuriantly on 2% grape-sugar agar. Upon gelatin at room tempera- 

 ture the growth is limited and the colonies are similar to those on agar. 

 There is no liquefaction. Old gelatin cultures are distinguished by an 

 orange-red color. 



Agar Plate. — (a) Natural size: In the depth the col- 

 onies are round and slight. On the surface they grow 

 well, and are circular, with a yellowish- white, faint, finely 

 granular nucleus and a narrow, pale, peripheral zone. 



1 By overstaining with hematoxylin and differentiating with glacial 

 acetic acid-glycerin mixture, and counterstaining with eosin, Eppinger 

 has convinced himself that the long threads consist of shorter and 

 longer rods in a sheath. 



