442 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



LitmiiK milk: — Defolorized. No coa.nnlation after six weeks; tlie reaction is neutral; there 

 may be a slijilitly pink rinu' on tlie tube wall. 



tSti(/ar (jclatin in deep stab. — ^'ery faint development. 



RotioUc acid. — Does not seem to have much effect on the color. 



Tndol prodwtion. — Doubtful reaction. 



Relation to temperatuye. — Does not grow at 35° to o<)0 C. 



Bacillus refractans. 



Isolated from the water of the Schuylkill Eiver. Karo. A short, thick, round-ended, non- 

 motile bacillus, of medium size, generally in pairs, and sometimes occurring iu somewhat larger 

 forms. It shows a tendency to gather in clumps. 



Colonies in (jelalin. — On the second day the surface colonies are round, white, slightly 

 elevated, refracting disks, about 1 nmi. in diameter, with sharply defined outlines. Under a low 

 power they are rather dark bi-ownish and refracting, apparently made up of rounded, brownish 

 masses, closely packed together. They have sharply defined outlines and sometimes darker 

 centers. The deep colonies are rounded, brownish, granular, and sharply defined. After two or 

 three days the surface colonies all seem to have increased somewhat in diameter and thickness, 

 and show a marked "crimping" or radial folding near their margin, so that under a low power 

 the colonies may have scalloped outlines. 



Gelatin xlanf. — A narrow, white, shining, rather thick, membranous growth, which is thrown 

 up into very numerous delicate wrinkles; the margin is finely irregular and sharply defined. 



Acid fjelatin. — Growth is thinner and nuich less wrinkled. 



Aejar .slant. — Narrow, thin, semitranslucent stripe of confluent small colonies. 



Bouillon. — Somewhat clouded, with some flocculi at surface and a whitish sediment at bottom; 

 a thin, imperfect, delicate pellicle on the surface may be seen. 



I'otato. — Scanty growth of grayish or brownish gray, small, discrete colonies. 



Lit mm mill: — No effect after a month. 



Siujar (jelatin in deep stab. — Development only very faint, if any. 



Ro.snlic acid. — No marked effect is produced; seems to be very slightly lighter in color after 

 some time. 



Indol production. — Negative; does not grow vigorously. 



Relation to temperature. — Grows at the temperature of the room and at 35° to 30° 0. 



Bacillus dormitator. 



Isolated from the water of the Schuylkill Eiver. Observed but once. A medium sized, non- 

 motile bacillus, with conical ends. It is quite variable in length, generally rather long, and occurs 

 singly, ill pairs, and in threads; no spore formation has been observed. 



Colonies. — On the second day the colonies appear as yellowish points, and there is evidence of 

 liquefaction around them. Under a low magnifying power they are seen to be yellow, faintly 

 granular, rough masses, with sharply defined bulging outlines. Some are surrounded by a zone 

 of clear liquefied gelatin. The colonies never attain any considerable size, but usually are lass 

 than 1 mm. in diameter, and float in rather large, circular areas of clear li(iuefle(l gelatin. 



Gelatin .stab. — Liiiuefaction generally in funnel form, subject to a good deal of variation in 

 different cultures. The liquefied gelatin is densely clouded and yellow in color, while at the 

 bottom of the liquefaction there is a thick, flocculent deposit of a bright yellow color; just above 

 this yellow mass the liquefied gelatin may be less densely clouded. The liquefied gelatin has a 

 slightly alkaline reaction. 



Acid (jelatin. — No development. 



Agar slant. — A bright yellow, shining, translucent growth, not spreading widely. 



Bouillon.— ClondeA and yellowish sediments; an imperfect yellowish pellicle may be formed on 

 the surface. 



Potato. — No growth. 



