450 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Si((/tiy (ichtiin in deep stah. — Fair development with the production of gas; there is UO' 

 liquefaction. 



Hosoltc acid. — Grows well without producing any marked change in color. 



Indol production. — Negative. 



Relation to temperature. — It seems to grow very slowly at 35° to 30° C. 



Bacillus janthlnus (Zojif ). 



Isolated Irom the water of the Schuylkill River. A medium-sized, generally short, motile 

 bacillus, with rounded ends, sometimes growing in long forms and threads; it has a polar flagellum; 

 no spore formation observed. 



Colonies in {/elatin. — On the second or third day the surface colonies are thin, translucent, 

 slightly opalescent expausions, with irregular, sharply defined outlines, and a diameter of several 

 millimeters; toward the center a grayish haziness maybe seen. Under a low power the colony 

 is thin and translucent, and shows very numerous fine lines, running in various directions and 

 sometimes branching; the outline is irregular but sharply defined. Toward the center the colony 

 has a slightly yellowish tint, and there may be a refractive central nucleus of the same color; the 

 deep colonies are rounded or slightly irregular, brownish in color, finely granular, with smooth, 

 sharply defined outlines. The surface colonies soon become grayish white throughout and denser; 

 later a violet color appears, generally at the center, and the colony begins to sink into the gelatin,, 

 which is slowly liquefied beneath it. After a few days the colonies have a deep black-violet color, 

 and are sunken in the gelatin, the liquefaction of which never spreads very far beyond the colony. 



Gelatin slant. — Forms a deep furrow lined by a membrane; at first grayish and later becoming- 

 violet in color. 



Gelatin stab. — At first a smooth, shining, grayish white surface expansion, which spreads 

 rather widely and has irregular margins; this soon becomes violet iu color and sinks in the 

 gelatin, forming, after some time, a deep, rather irregular excavation, lined by a violet-colored 

 membrane, beneath which slow liquefaction occurs; the excavation is usually narrower at the 

 top, so that when it has reached the tube wall a ring of nonliquefied gelatiu remains above; 

 the liquefied gelatin is somewhat clouded, and there is some grayish or violet colored sediment; 

 there is a fair growth m line of inoculation of confluent brownish colonies. 



Acid gelatin. — Grows well; produces an alkaline reaction. 



A(jar slant. — Grayish, semitransluccnt, smooth, shining growth, with wavy, sharply defined 

 outlines, spreading rather widely below ; this later becomes deep violet iu color and membranous 

 in character. 



Bouillon. — Clouded; a dark, violet-colored membrane forms on the surface; after a time the 

 bouillon acquires a smoky violet tint and there may be a violet-colored sediment. 



Potato. — Dense black, violet, membranous, coherent layer, sometimes shining, and in some- 

 places having a granular appearance, due to minute and numerous delicate wrinkles. 



Litmus milk. — Decolorized with the formation of a dense, coherent, wrinkled, dark violet- 

 colored membrane on the surface, and the milk acquires a violet color; there is no coagulation ; the 

 reaction is alkaline. 



tiugar {/elatin in deep stab, — Fair growth of discrete and confluent colonies; no gas is produced. 



Rosolic acid. — Color is deepened; a violet-colored membrane forms on the surface. 



Indol production. — Negative or doubtful. 



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



Remarks. — This bacillus was observed quite frequently in the early spring When it was first 

 seen ; it has not appeared for some mouths. The bacillus janthinus seems to be a widely distributed 

 species. According to Fliigge (Die Mikroorganismen) it was generally described by Zopf, and is 

 probably identical with a bacillus described by Hueppe and a species fcund in the Hygienic 

 Institute at Goettiugen. Plagge and Proskauer met with it in the water supply of Berlin (Bericht 

 fiber die Untersuchungen des Berliner Leituugswasser, Zeitschrift fiir Hygiene, Bd. II, 1887, 

 p. -103). Maschek and Zimmermann each found it iu their resj)ective investigations (Lustig, Diag- 

 nostica dei batteri delle acque). Jordan (Report of the State Board of Health of Massachusetts^ 



