MEMOIRS OF THE NATIONAL ACADE:\IY OF SCIENCES. 453 



])laqucs and buds. Tuft like outpowtlis of slioit fibrils may be seen on tliese. Liquefaction soon 

 occurs, and the surface colony becomes surrounded by a wide zone of cloudy, liquefied gi'latin. 

 F^uder a low power tlie colony is now seen to bi; nuicli denser and may have a greenish brown 

 shimmer. It may present the appearance of being broken up into a mass of closely 

 packed clumps or marked by indistinct crooked lines. The liquefied area is dense, 

 brownish, and granular, and is limited at the jieriphery by a zone of closely packed, 

 radiating brown lines. Beyond this, again, a thin, translucent, almost invisible border 

 lies on the nonliquefled gelatin. This has a very irregular outline. (See PI. II, fig. 

 1.) In the liquefied zone motion of a circulatory character may be made out. In older 

 C()lonies the growth in the liquefied area is seen to have acquired a luenibranous 

 character and to be continuous with the original colony at the center, so that the 

 whole colony consists of a rather viscid membrane lying in a depression containing 

 liquefied gelatin. If a plate containing numerous colonies be examined with a low 

 power after about thirty hours (PI. II, fig. .!), the young surface colonies may be seen 

 to have very grotesque and irregular outlines. 



Geldtin sidli. — On the third day a rounded, rather deep, saucer-shaped liquefaction 

 has formed not yet extending to the tube wall. The liquefied gelatin is clouded, and 

 there is a mycoderm on the surface which recalls in its appearance frosted glass. By 

 the sixth day liquefaction has extended to the tube wall and downward for a consid- Ym^i. 

 erable distance, the li(iuefied gelatin being separated from the nonlicpiefied by a nearly 

 horizontal plane. (See fig. 14.) The liquefied gelatin is nearly clear, and there is a tough, 

 yellowish white, coarsely wrinkled mycoderm on the surface and some sediment at the bottom. 

 There is only slight growth in the line of inoculation. The reaction of the liquefied gelatin is 

 alkaline. 



Acid gelatin. — Growth is retarded. 



Agar slant. — Creamy white layer extending to the wall of the tube on each side, except near 

 the top of the slant, where it becomes narrow. The growth is smooth, homogenous, and shining. 

 A few slight wrinkles may sometimes be observed. By transmitted light the growth is white and 

 not translucent. The agar may take on a faint green tint after a time. 



Bouillon. — Clouded. A thin, imperfect pellicle forms on the surface and there is some 

 sediment. 



Potato.— A rapidly growing, widely spreading, light brown, rather thin but dense and 

 coherent layer which is thrown up into very numerous delicate wrinkles and folds which cross 

 one another in various directions, giving the potato the appearance of being covered by a 

 network. 



Litmus mill;. — Action is slow; after a week partly decolorized from the bottom ; later, coagula- 

 tion and complete decolorization ; the coagulum is viscid and above it is seen a layer of cloudy 

 serum; there is a slightly bluish ring on the wall of the tube above the level of the liquid; the 

 reaction is neutral. 



Sugar gelatin in deep stab. — Slight dcvelopnuMit ; no gas production. 



Eosolic acid. — No vigorous growth; little or no change in color. 



Indol production. — lieaction is faint or doubtful; does not produce nitrites. 



Relation to tem])erature. — Grows well at the temperature of the room and at 35° to 36° C. 



Bacillus crinitus. 



Isolated IVom the water of the Schuylkill Piver. Not common. A large, nonmotHe bacillus 

 with bluet ends, occurring usually in chains and segmented threads. Forms oval or rounded 



spores, which arc situated near one end of a short segment or rod. (See fig. lo.) 



/^ Colonies In gelatin.— Ahont the second day or earlier the surface colonies appear as 



round, shining, whitish, seniitranslucent disks, 1 mm. to 2 mm. in diameter, and with a 



Ql smooth, sharply defined outline: they have a viscid consistency, adhering to the "loop" 



FiG.15. and stringing out into viscid threads. Under a low magnifying power they are dark, higiily 



granular, and have a smooth, shai'idy defined outlhie; the deep colonies are dark and 



opaque, usually coarsely granular at margin: the outline is rounded or oval and sharply defined. 



On the third dav the colonies arc larger, and consist of more or less dcu.se. felt-like pellicles, 



