462 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Litmns millc. — Seems to become n deeper blue and to be decolorized from the bottom up; it 

 is probably not coagulated. Alter some time the milk becomes alkaline. 

 Huijar (jdaiin in deep stab. — No growth. 



Eosolic acid. — Somewhat decolorized after some time; reacts alkaline. 

 Indol production. — Negative. 

 licldtioii to leiiipcratitrc. — Grows at the temperature of the room and at 35° to 3()°C. 



Bacillus luultistriatus. 



Isolated from the water of the Schuylkill River. Not common. A medium-sized short, «/of(7e 

 bacillus with rounded ends. Somewhat variable in length and occurring often in pairs. It has a 

 polar tlagellum; no spore formation observed. 



Coloiiiea in rjelatin. — About the second day the surface colonies are rounded grayish, white, 

 semitranslucent disks, 1 mm. to 2 mm. in diameter. (PI. II, fig. 12.) Under a low power they are 

 more or less dark Ijrownish in color, rather dense toward the center, but becoming thinner toward 

 the margin. The outlines are smooth or slightly irregular, and sharply delined. A striking thing 

 in the appearance of these colonies under the low power is the presence of dark brownish zigzag- 

 and wavy lines and bundles of lines of various lengths, streaming toward the periphery from their 

 centers, where there is often a dark nucleus. The deei> colonies under a low power are dense, 

 granular, brownish in color, and in some cases slightly greenish toward their centers. They are 

 rounded or irregularlj- oval and sharply detined in outline. In some deep colonies dark, radiating, 

 wavy lines have been observed. In a few days the surface colonies become denser and yellowish 

 white in color and may increase somewhat in size. They very slowly licprefy the gelatin into 

 "which they .slowly sink, but no zone of liquefaction is seen around them. 



Gelatiu stab. — Thick-beaded, whitish cord first forms along the line of inoculation, while there 

 is an irregularly outlined, thick, whitish expansion which sinks gradually into the gelatin. After 

 about ten days lirpiefaction begins all along the line of inoculation and siireads laterally to the 

 tube wall, all the gelatin being eventually liquetied. The liquefied gelatin is tilled with scattered 

 whitish tlocculi and there is a dense, whitish deposit at the bottom, while on the surface a dense, 

 thick, whitish clumiJ may be seen. 



Acid, gelatin. — Good growth, though liquefaction is not so vigorous along the line of inocula- 

 tion. The liquefied acid gelatiu is neutral or slightly alkaline. 



A(jaf slant. — Semitranshicent narrow stripe with scalloi)ed or wavy margins. 



Bouillon. — Clouded and a stringy sediment. A thin pellicle which may have whitish, dry 

 flakes in it forms after a time. 



Potato. — Grayish or creamy, viscid-looking, thick, shining, widely spreading growth. 



Litmus milk. — Decolorized and coagulated; the clot is friable and more or less pink, and the 

 serum is clouded. There is a reddish ring in the tube wall. Reaction is acid or neutral. 



Sugar gelatin in deep stub. — Mgorous growth with marked gas production; there is also 

 liquefaction. 



Rosolic acid. — Color is deepened. 



Indol production. — Fair reaction; does not produce nitrites. 



Relation to temperature. — Grows at the temperature of tlie room and at 3.5° to 36° C. 



Bacillus ceiitrifugans. 



(Variety a.) 



Isolated from the water of the Schirylkill River. In the summer .occurs abundantly, both 

 in the Schuylkill and Delaware water. A medium sized motile bacillus with rounded ends^ 

 sometimes in pairs and iu long forms. It has a polar tlagellum; no spore formation observed. 



Colonies in gelatin. — After twenty-four to foi'ty-eight hours the surface colonies are round, 

 saucer-shaped depressions, containing faintly hazy, liquefied gelatin, several millimeters iu diame- 

 ter, which rapidly increase in size. About the center there may be a few grayish flocculi, while 

 at the margin they are well detined by a grayish line. Under a low power the liiiuefied gelatin is 

 granular in appearance, and a circulating motion may be seen in it, while scattered, dark, granular 



