MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 449 



Agar .slant. — Grayish, seiiiitransluceut stripe, with sharply (lelined, wavy marjiiiis: tlie agar 

 becomes tiiioresceiit. 



BoiuUon. — Clouded ; on the surface a delicate grayish pellicle I'orins, while the bouillon is blue- 

 greeu fluorescent; there is a stringy sediment. 



Potato. — Chocolate-colored, viscid-looking, rather thick, and rather widely spreading growth. 



Litiiiiis milk. — Slow coagulation and cloudy serum containing flocculi in susjiension; the clot 

 is jelly-like and decolorized, and is slowly dissolved; there is a pink ling on tube wall above a 

 pale bluish ring; the reaction is alkaline. 



Suijar gelatin in deep .stab. — Very faint development. 



Hosolic acid. — CoU)r is deepened. 



Indol production. — The reaction is doubtful or faint; the addition of nitrite is necessary. 



Relation to temperature. — Does not grow at 35° to 36° C. 



Bacillus fluoresceus mutabilis. 



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

 rounded ends, occurring often in pairs. It has one or two flagella at one end; no spore formation 

 observed. 



Colonies in gelatin. — On the second or third day the surface colonies appear to consist of 

 whitish, sometimes greenish flocculi, lying in saucer-shaped licpiefactions seveial millimeters in 

 diameter; in some cases the colonies are more or less sunken, greenish, membranous expansions. 

 This difference seems to be dependent on the gelatin used. A blue-green fluorescence may 

 sometimes be observed in the medium. Under a low-magnifying power a dark, dense mass is 

 seen at the center of the liquefaction; around this a zone densely tilled with granular brownish 

 material, often in clumps, and this, in turn, bounded at the periphery by a more or 

 less distinct fringe of closely lying, parallel filaments. In other preparations the 

 colony is seen under the low i)ower to be membranous in character, and to consist of a 

 dark greenish, central, dense mass, which merges into a thin peripheral zone, with 

 wavy, sharply defined margins, and marked by numerous dark wavy and irregular 

 radiating lines. The colony is sunken in the gelatin at the center, from which lique- 

 faction seems to spread to the periphery and the colony is broken up. The deep 

 colonies are rounded or oval, dark brown, sometimes greenish, and have sharply- 

 defined contours; they are often marked by irregular, dark, radiating lines; when 

 they come to the surface they form an expansion which seems to be made up of 

 closely packed, coiled and twisted, brownish cords, and this may become limited by a 

 short fringe of radiating fibrils. 



Gelatin s<a^.— Liquefaction in cup or deep saucer form, extending to the tube 

 wall, and afterwards having a level floor (fig. 10). The liquefied gelatin is clouded, 

 and a more or less well-defined mycoderm of a gray or sometimes greenish color forms 

 on the surface, while there is a whitish sediment at the bottom; the growth produces 

 more or less of a green color; the development along the line of inoculation consists of confluent, 

 brownish white colonies, and in older cultures a faint but distinct brownish coloration may be 

 seen in the gelatin around them if the tube be held against a white surface: this coloration is 

 characteristic, ami takes the form of a sharply defined, narrow zone, running all along the growth 

 on each side. 



Acid gelatin. — Grows well; no green color is produced, and the growth in line of inoculation 

 is faint; the liquefied gelatin is alkaline. 



Agar ulant. — Grayish, semitrauslucent stripe and irregular margins; the agar acquires a 

 greenish tint. 



Bouillon. — Clouded, with a thin grayish pellicle on the surface, and some sediment; the 

 bouillon acquires a green color. 



I'otato.—Biovrii, thick, viscid looking, uneven, not very widely spreading growth. 

 , Litmus mill,-. — Coagulated and decolorized; the clot is firm and the serum is clouded, hohling 

 flocculi in suspension; there is a bluish ring on the tube wall, and the reaction is alkaline: the 

 casein seems to be slowly dissolved. 

 S. Mis. 50 li!) 



XIJ 



