448 ACTINOMYCETES. 



Spontaneous motion is lacking. 



Staining Properties. — Stains with ordinary anilin 

 dyes, and by Weigert's modification of Gram's method, in 

 which anilin is used instead of alcohol after the iodin. 



According to Nocard, it does not stain well with the common anilin 

 dyes. According to Berestnew, it stains by Ziehl's method (Z. H. 

 xxix, 94) ; but according to Nocard, it does not. We could not 

 repeat the tests, as our culture proved to be dead. 



Requirements as Regards Temperature and Com- 

 position of Nutrient Media. — Not particular as to 

 nutrient medium; grows at room temperature, and espe- 

 cially at 37°. 



Gelatin Plate. — (a) Natural size: Scanty growth. 

 After ten days there are only minute, round, transparent, 

 shining colonies (66, v). 



(6) Magnified fifty times : The superficial and deep col- 

 onies appear as smooth-edged, shining, gray to grayish- 

 green masses in which no finer structure is distinguishable 

 (60, vi). 



Gelatin Stab. — Scanty; after twelve days the surface 

 growth is whitish and granular; that in the stab crumbly 

 (66, n). 



Agar Plate. — (a) Natural size: The superficial colonies 

 reach a size of 1 to 2 mm. , are yellowish-white, irregular 

 in form, and shining. The deep colonies remain tiny 

 (66, vii). 



(6) Enlarged fifty times: The surface colonies are similar 

 to those on gelatin plates. The deep colonies are bright 

 yellow, delicate, distinctly filamentous, and curly in struc- 

 ture (66, viii ). 



Agar Stab. — About like the gelatin stab. Upon the 

 surface of the agar there forms a whitish, coarsely granular 

 mass, which is very irregular in shape because of fissures. 

 The faintly colored growth shows air mycelium in spots 

 (Nocard). 



Agar Streak. — After eight days there is formed a gray 

 to yellowish- white growth, consisting of transparent col- 

 onies, with a rough, finely fissured surface. The colonies 

 are slightly or not at all connected. The water of conden- 

 sation is clear, with slight grayish- white precipitate. After 



