MEMOIRS OF THE 2TATIONAL ACADEMY OF SCIENCES. 441 



Bacillus nexibilis. 



Isolated from the water of the Schuylkill Kivei'. A inediiiinsized, niotih! bacillus, with 

 rounded euds, occurring often in pairs in loiiy forms and sometimes in chains and clumps; it has 

 a terminal Hagellum; no spore formation observed. 



Colonics in (jelaUn.— On the second or third day the surface colonies, if not numerous, are 

 thin, grayish, trauslucent, somewhat opalescent expansions, with irregular sinuous outlines and 

 diameters of several millimeters. Under a low power they are thin, slightly brownish in tint, and 

 slightly granular, becoming more transhicent at the margin, which is very irregular, tinely sinuous 

 or dentated, and sharply defined. The deep colonies under the low power are rounded or slightly 

 irregular in outline, and have sharp contours. They are slightly granular, and are of a brownish 

 color toward their centers. After a few days the surface colonies have become slightly denser and 

 have acquired a faint greenish tint. Under a low power they may be seen to be marked near their 

 margins by bundles of faint radiating lines. If they are well separated, under some circumstances 

 broad lobe-like new growths on the surface of the gelatin may ai)pear ar different points on their 

 margins; these have the appearance of the parent colony when it was younger, and they may 

 grow to be nearly as large, so that a very irregular outline is given to the ci.'lonies. 



Grldtin slant. — A nearly smooth, shining, not translucent stripe, grayish by reflected light, 

 brownish Mhite by transmitted light, not spreading widely, and with irregular, sharply defined 

 margins. The gelatin may acquire a very faint, browuish green tint. 



Acid (jelatin. — Grows well. 



Afiar slunt. — Thin, semitranslucent, grayish stripe, not spreading widely, ;ind having irregular 

 or scalloped margins; agar acquires a greenish tint after a time. 



Bouillon. — Clouded; some stringy sediment at bottom and some Hocculi near surface; bouillon 

 acquires a faint greenish tint. 



Fotato. — Brown, viscid-looking, thick layer, spreading rather widely. 



Litmus mill-. — Becomes slowly pink; no coagulation after a month at the temperature of the 

 room ; reaction is acid. 



Siiyar (jelatin in deep stab. — Little or no develoxmient. 



Eosolic acid. — Color becomes less; reaction is neutral or slightly alkaline. 



Tndid production. — Faint reaction; does not i)roduce nitrite. 



Relation to temperature. — Does not grow at .35^ to 30° O. 



Bacillus tiogeiisis. 



Isolated from the water of the Schuylkill Biver. Bather common at one time. A medium- 

 sized nonntotiic liacillus. with rounded ends and generally rather i)lunip. Occurs singly, in pairs^ 

 and sometimes in chains of three or four elements, as well as in long forms. Xo spore formatioii 

 observed. 



Colonies in (jelatin. — About the second day the surface colonies are rounded, milk-white, shining, 

 elevated, not translucent disks, about 2 nun. in diameter. Under a low power they are dark and 

 rather opaque, with a slight greenish shimmer, becoming thinner, brownish, and granular toward 

 their margins, where they are nearly clear. Their outlines are rounded, smooth, and sharply defined. 

 The deep colonies, under a low power, are rounded or slightly irregular, dark, granular, and sharply 

 contoured. They have a faint brown, greenish shimmer at their centers. In a roll culture five days 

 old the main central portion of a surface colony could be removed with the platinum loop as a 

 white disk. 



Gelatin slant. — A thick, white, shining, smooth, narrow layer, with slightly irregular. shar|(ly 

 defined margins. 



Acid gelatin. — Grows well. 



.{(jar .s7rtH^— Semitranslucent, grayish, not widely spreading layer. 



Ilouillon. — Clouded and whitish stringy sediment. 



Potato. — Dirty, browuish gray, moist, viscid-looking, not very thick, but widely spreading- 

 layer. 



