NON-PATHOGENIC BACILLI. 641 



Found in uu filtered river water. 



Morphology. Bacilli with round ends, 1.5 to 2 /< long 1 and about three or 

 four times as long- as broad ; usually united in pairs. 



Biological Characters. An aerobic, liquefying, motile, chromogenic ba- 

 cillus. Produces a fluorescent green pigment. Spore formation not ob- 

 served. Grows rapidly at the room temperature in the usual culture media. 

 Upon gelatin plates the deep colonies appear under a low power as finely 

 granular discs with a smooth contour ; when they come to the surface the 

 margin is fringed and hair-like offshoots extend into the gelatin ; at the 

 same time liquefaction occurs around the colonies and rapidly extends ; each 

 liquefying 1 colony is surrounded by a fluorescent green zone, and the lique- 

 fied gelatin has the same color. In gelatin stick cultures liquefaction in 

 funnel shape is already seen on the second day, and the liquefied gelatin is 

 filled with whitish flocculi, while a slight green, fluorescence is seen near 

 the surface ; liquefaction progresses rapidly, and a viscid layer of a greenish- 

 white color forms upon the surface, while the liquefied gelatin below is more 

 or less clouded and has a fluorescent green color ; an abundant flocculent 

 deposit is seen at the bottom of the tube. Upon the surface of agar a 

 smooth, glistening, greenish- white layer is formed along the line of inocula- 

 tion and the agar quickly acquires a green color. In bouillon, at the end of 

 two days, the liquid is clouded, and later a thin, greenish-white layer forms 

 upon the surface, while the bouillon acquires a green color. Upon potato 

 a chocolate-colored, moist-shining layer quickly extends over the entire 

 surface. 



290. BACILLUS VIOLACEUS. 



First found in the water of the Spree at Berlin, and since by Frankland in 

 the water of the Thames and of the Lea. 



Morphology. Bacilli with round ends, about 1.7 /t longand 0.8 /* broad; 

 usually in pairs; may grow out into long filaments. 



Biological Characters. An aerobic and facultative anaerobic, liqiiefy- 

 ing, motile, chromogenic bacillus. Produces a dark -violet pigment. Forms 

 oval spores, which are located in the centre of the rods. Upon gelatin 

 plates, at the end of two days, the colonies are seen to be irregular in out- 

 line and granular; on the fourth day a funnel of liquefied gelatin is formed 

 by each colony, and under a low power an opaque mass surrounded by con- 

 voluted, filamentous offshoots is seen at the bottom of this ; later the funnel 

 of liquefied gelatin increases in dimensions and the colony acquires a deep- 

 violet color. In gelatin stick cultures liquefaction occurs rapidly along the 

 line of inoculation as a funnel-shaped sac ; the liquefied gelatin is clouded, 

 and a violet-colored deposit is seen at the bottom of the tube. Upon the sur- 

 face of agar a smooth, shining layer of a deep-violet color is quickly de- 

 veloped. Upon potato growth is limited to the line of inoculation and a 

 dark- violet stripe is slowly developed. Blood serum is liquefied by this 1 

 bacillus. 



291. BACILLUS SULFUREUM (Holschewnikoff). 



Morphology. Bacilli with round ends, from 1.6 to 2 A p long and 0.5 n 

 broad. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile, chromogenic'bacillus. Forms, in the absence of oxygen, a red- 

 dish-brown or red pigment. Produces sulphuretted hydrogen in sterilized urine 

 and certain other media when cultivated in the absence of oxygen. Spore 

 formation not observed. Grows in the usual culture media at the room tem- 

 perature also- in the incubating oven. Upon gelatin plates small, puncti- 

 form colonies are developed within forty -eight hours, which, when they 

 reach the surface, cause a funnel-shaped liquefaction ; as the liquefaction 

 progresses very slowly the liquefied gelatin is dried and the funnel- shaped 

 cavities are filled with air. lu gelatin stick cultures small colonies are de- 

 veloped along the line of puncture, and liquefaction in funnel shape occurs 



