BACTERIUM TYPHI. 233 



(b) Magnified fifty times. Superficial: Up to forty-eight 

 hours the colony is entirely colorless and transparent. The 

 border is smooth and lobed. The surface presents wavy 

 elevations, and numerous branching, strongly reflecting, 

 whitish, winding lines, which look like incisions or 

 scratches. The colony then appears fairly homogeneous, 

 grayish-yellow, with white, curved lines and bands extend- 

 ing from the center, between which are to be seen concen- 

 trically arranged lines. These lines are the expression of 

 folds in the colony (17, i). When more highly magnified 

 (X 150) (17, n), indistinct parallel curved lines may be 

 seen. Not infrequently the superficial colony is thicker, 

 and then there occurs, instead of the windings, etc., in 

 the yellowish almost opaque appearing colony, only an 

 indistinct development of figures resembling hen-tracks. 

 (Compare 19, VI. ) All the forms reproduced in Plates 18 

 and 19 of the Bact. coli may also occur; also spirals and 

 tail-like appendages, as in Plate 19, i. Deep : Round to 

 roundish colonies, bright yellow, homogeneous, delicate, 

 shaded with gray, with even borders (16, vn; compare also 

 19, v). 



Gelatin Stab. — Stab : Thread-like, slightly granular, 

 whitish-gray (16, in). Surface growth: Thin, white, gray- 

 ish-green, iridescent, extremely transparent, roundish, 

 notched, with a dry luster, not elevated, extending to the 

 glass (16, iv). 



Gelatin Streak. — Somewhat spreading, white and thin 

 growth, as on the surface of the puncture. 



Agar Plate. — 



(a) Natural size. Superficial: Irregular, roundish, gray- 

 ish-white, shining, slightly elevated colonies. Deep : Punc- 

 tiform, gray (17, iv). 



(b) Magnified sixty times. Superficial colonies : Round or 

 roundish, smooth border, bright yellowish, becoming darker 

 toward the middle, finely to coarsely punctated and trans- 

 parent at the edge; from the center usually dark yellow, 

 winding or jagged lines extend outward; morulae are rare 

 (17, vi). Deep: Roundish to whetstone-shaped, border 

 smooth or rough, brownish-yellow, opaque, without inter- 

 nal markings or finely granular (17, v). 



Agar Stab. — Stab: Thread-like, sometimes a little 



