136 IMPORTANT VABIETIE8 OF FISSION-FUNGI. 



Media.— Growth rather slow, best at 37°. Above 47° no 

 growth (Arloing). 



They also grow more slowly but more luxuriantly upon feebly acid 

 nutrient media (hydrochloric acid, tartaric acid). Grow more slowly 

 but with greater vitality at 23° than at 37°. Especially good growth 

 occurs in exhausted cholera or pyocyaneum bouillon either after or 

 without filtration (Tnrr6, C. B. xvil, 865). 



Gelatin Plates. — (a) Natural size: Very small, 

 whitish, roundish, flat, rarely slightly elevated colonies, 

 which do not grow perceptibly after a longer time (1, v). 



(&) Magnified fifty times. Superficial: Roundish colonies 

 with smooth border (1, vii e), but may present also 

 wavy, scalloped, serrated, as well as fringed and torn 

 forms (1, VI e). Color is gray to yellowish, structure 

 delicately punctate to finely granular, usually transparent. 

 Deep lying: Roundish to whetstone-shaped, rough or 

 smooth border, somewhat more coarsely punctate than the 

 superficial (1, vii i; vi i). 



Gelatin Stab. — Stab : At first thread-shaped ; after a 

 short time there appear numerous small nodules in the 

 stab (1, ii). Surface growth is like that in the gelatin 

 plate. ^ 



Gelatin Streak. — Narrow, beautiful, delicate growth 

 along the streak, beset at the borders with little nodules. 



Agar Plates. — (a) Natural size: As on gelatin plates. - 



(h) Magnified fifty times. Superficial: Spherical colonies 

 with delicately punctate edge, transparent, grayish-yellow, 

 at first very delicately punctated, later (fourteen days) at 

 times granular ; frequently there is a distinct appearance 

 of lobulation (1, vine). Deep lying : Smaller and some- 

 what darker (1, vm i). 



Glycerin-ascites-agar. — Colonies distinctly more lux- 

 uriant. From the periphery of the superficial colonies 

 there often extend outward numerous shorter or longer coil- 

 ing chains, so that the colony appears not unlike a young 

 anthrax colony. Also, the granulation in the interior of 

 the colonies is somewhat more marked than upon agar. 



'Liquefaction, according to German authors, is very rare. Pane 

 saw the Strept. pyogenes from human abscesses at a temperature above 

 24° produce regularly liquefaction of gelatin which he had so pre- 

 pared artificially that it was first melted at 30° (C. B. xvi, 228). 



