MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 465 



lio-wUc acid. — Color deepened. 



Indol production. — Negative. 



Relation to tcnqieruture. — Grows at tlie temperature of the room; its growth at •3.")^ to 36° C. 



is doubtful. 



Bacillus nebulosus. 



Isolated from the water of the Schuylkill River. A medium-sized, motile bacillus, with rounded 

 ends, occurring singly and in ])airs; in length it is somewhat variable. It has a polar flagellum; 

 no spore formation observed. 



Colonics in gelatin. — On the third day the typical surface colony is a thin, gray, translucent, 

 hazy, round, outlined expansion, with a well-marked whitish center, surrounded by a whitish ring. 

 (See ri. II, fig. 13.) The diameter maybe about 3 mm. Under a low ])o\ver a dark brownish, 

 granuhir nucleus is .seen at the center, around which a dark, finely granular zone extends about 

 halfway to the periphery and then gives way rather abruptly, by the appearance in it of discrete 

 and confluent, sharply defined, translucent areas, to a very thin, transparent zone, which ends at 

 the welldeftued, nearly smootli margin. The deep colonies are rounded, dark, and granular, 

 sometimes brown-green in tint. 



Gelatin slant. — A viscid whitish layer lines a shallow furrow, on each side of which thin, Iiazy, 

 short, lateral outgrowths on the surface of the gelatiu are seen, giving the growth a featiiered 

 appearance. By transmitted light the layer in the fissure is yellowish white. There is slow 

 liquefaction. 



Acid (jelatin. — Does not seem to grow. 



Agar slant. — A very thin, translucent sti'ipe with irregular margins. 



Bouillon. — Clouded and whitish sediment. 



Potato. — Very scanty growth, if any. 



Litmnsmill-. — No definite coagulation; it is decolorized and the casein seems to be dissolved. 

 On the surface a broken, wrinkled, whitish mycoderm. The reaction is alkaline. 



Sugar gelatin in dee}) stab. — Fair growth, with some gas formation. 



Fosolie acid. — The effect is doubtful. The color is probably deepened. 



Indol prod uel ion. — Negative. 



Relation to temperature. — Grows at the temperature of the room and at 35° to 36° C. 



Proteus mirabilis (Hauscr).' 



Isolated from the water of the Schuylkill River. A rather small, motile bacillus with blunt 

 ends, occurring singly, in pairs, and in long forms. It has a number of tlagella; no si)ore formation 

 observed. 



Colonies in gelatin. — xVfter twenty-four to forty-eight hours, saucer-shaped lique- 

 factions, which are clouded and may have a whitish s])ot at their centers, are seen. 

 They may have a diameter of several millimeters. (See PI. II, fig. 14.) Under a low 

 power the liquefied gelatin is coarsely granular, brownish, and dense toward the 

 center, somewhat less so toward the periphery, where it is limited by a more or less 

 distinct fringe of radiating fibrils. The deep colonies are rounded, granular, and 

 brownish, not dense, and have sharp contours. In addition to these, this bacillus 

 forms also other kinds of colonies which are highly characteristic. If a well developed 

 ]date be examined with a low magnifying power, small, translucent, elongated, gen- 

 erally spindle-shaped bodies may be seen in great numbers scattered through the gelatin 

 among the other colonies. They usually taper at one or both ends into a sometimes 

 branching filament and often have the appearance, in their thicker positions, of being- 

 made up of rouleaux of minute rounded colonies. Other irregular forms are seen 

 These growths are essentially like the photographs of Proteus mirabilis given by Ilauser. 



Gelatin stah. — Liquefaction in saucer form extending to the tube wall and slowly fio.29. 

 downward, the flow becoming level. Along the line of the stab there is a fair growth 

 of discrete and confluent colonies. Near the surface a few short lateral outgrowths from the line 

 of iuoculation may appear. (See fig. 20.) The liquefied gelatin is clouded and there is a thick, 

 flocculent, whitish sediment after a time. Liquefaction does not progress rapidly. 



' Hausek, G. Ueber Fiiulnissbakterien und deren Beziehungen zur Septiciimie. Leipzig, 1885. 

 S. Mis. 50 30 



