356 IMPORTANT VARIETIES OF FISSION-FUNGI. 



ish to white growths, with a moist luster, smooth borders, 

 a little elevated, transparent (47, viii, ix), sometimes 

 resembling the colon colonies. (Compare also 18, viii.) 



(h) Magnified sixty times. Deep colonies : Irregular 

 roundish and whetstone-shaped, with smooth or slightly 

 roughened borders, with delicate or medium-sized granules, 

 and pale yellow (48, i, ii, iii, right). Only after standing a 

 very long time do they become darker colored (48, v) or 

 present a brown central point with gray or greenish zones 

 (48, iv). Superficial colonies : Roundish, faintly yellowish, 

 transparent, at first extremely finely punctated (48, i, ii), 

 later coarsely crumbly (48, iii). The picture after twenty 

 days is shown in Plate 48, iv. 



Agar Stab. — Stab : Whitish-gray, not characteristic, 

 thread-like; later rough (47, vi). Surface growth: At 

 first light brownish-gray, with a moist luster, wavy, 

 smooth border, a little elevated, and after a longer time 

 becoming colored a yellowish-brown (47, vii). The agar 

 streak corresponds to this (47, v). 



Serum Culture. — Solidified blood-serum at incubator 

 temperature is rapidly liquefied. 



Bouillon. — At incubator temperature after ten to six- 

 teen hours there is a diffuse cloudiness, very often with the 

 formation of a distinct, more or less rigid or friable pelli- 

 cle. In cultures freshly isolated from the body, pellicle 

 formation may sometimes be entirely absent; when the 

 reaction is strongh^ alkaline, the pellicle becomes thicker 

 and firmer (Cramer). Sometimes we have met with very 

 compact, wrinkled pellicles, but in a subsequent culture 

 upon the same nutrient medium nothing striking was ob- 

 served. 



Milk. — Koch described the vibrio cholerje as having 

 no particular effect upon milk. More recently many 

 writers have isolated cholera vibriones from typical cases 

 of cholera which coagulate milk. The formation of acid 

 appears to most of the authors to be sufficient explanation 

 of the coagulation; a rennet ferment has not been demon- 

 strated. For details, see Schoffer (A. G. A. xi, 262). 



Potato Culture. — Upon faintly acid potato there is 

 either no growth or it occurs only at incubator tempera- 

 ture. According to Krannhals (0. B, xm, 33), there are 



