NON-PATHOGENIC BACILLI. 



Biological Characters. An aerobic, non-liquefying, actively motile 

 bacillus. Spore formation not observed. Grows rather quickly in the usual 

 culture media at the room temperature. Upon gelatin plates the deep colo- 

 nies are small, spherical or oval, finely granular, whitish or yellowish- 

 brown; the superficial colonies are whitish or brownish, elevated, hemi- 

 spherical, with sharply defined outlines, and about one /* in diameter. In 

 gelatin stick cultures a granular growth is slowly developed along the line 

 of puncture and a white layer about the point of inoculation ; at the end of 

 two to three weeks the upper part of the line of puncture forms a saucer or 

 flask-shaped cavity and the walls are covered with a white layer; there is, 

 however, no liquefaction of the gelatin. Upon agar plates the growth is 

 very characteristic : branches are given off from a central point ; these are 

 variously bent and give off numerous smaller, wavy branches ; these colo- 

 nies extend only upon the surface and may have a diameter of two to three 

 centimetres ; under a low power they are seen as very thin, finely granular, 

 yellowish layers with club-shaped branches. Upon potato forms a dirty- 

 white layer. 



FIG. 216. Bacterium Zopfli ; a, long filament with commencement of "ball formation"; b 

 shows the breaking up into short rods; c, further breaking up into spherical elements ; e,f, spirilla- 

 like filaments, x 740. (Kurth.) 



329. BACILLUS VENTRICULI (Raczynssky). 



Found in the stomach of dogs fed exclusively on meat. 



Morphology Bacilli from 1.5 to 3 /* long and 1 n thick; united in pairs 

 or in chains of four. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying, motile bacillus. Does not form spores. Grows slowly at the 

 room temperature. Upon gelatin plates forms round colonies, which are 

 opaque at the centre and become more transparent toward the margin, which 

 is surrounded by a dark contour. In gelatin stick cultures small, white, 

 punctiform colonies are developed along the line of puncture. Upon agar 

 a whitish layer is formed. This bacillus is said to cause the peptonization of 

 albuminous substances when the reaction is acid or neutral. 



