IX. 



NON-PATHOGENIC BACILLI. 

 A. Chroinogenic, Non-Liquefying Bacilli. 



237. BACTERIUM LUTEUM (List). 



Found in water. 



Morphology. Elliptical cells from 1.1 to 1.3 // long. 



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

 mogenic bacillus. Produces an orange-yellow pigment soluble in water, 

 alcohol, and ether; not changed by alkalies, but at once destroyed by acids. 

 Grows at the room temperature in the usual culture media. Upon gelatin 

 plates forms irregular colonies upon the surface, of slimy consistence and 

 orange-yellow in color ; under a low power these are seen to consist of many 

 club-shaped, coarsely granular, zpoglcea masses, each one of which is made 

 up of several segments. In gelatin stick cultures development occurs slowly 

 along the line of puncture and an orange-yellow layer forms on the surface. 

 In milk, at 30 C., a layer forms upon the surface in from twenty-four to 

 thirty hours, and the milk below has a pale-yellow color ; later coagulation 

 of the casein occurs. 



238. BACILLUS AURANTIACUS (Frankland). ' 



Found in well water. 



Morphology. Short, thick bacilli which vary greatly in their dimensions ; 

 sometimes associated in pairs ; often grow out into long filaments. 



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

 chromogenic bacillus. Forms an orange-colored pigment. Grows at the 

 room temperature in the usual culture media. Upon gelatin plates the super- 

 ficial colonies are homogeneous, opaque, elevated masses of a pale-orange 

 color ; the deep colonies spherical and granular. In gelatin stick cultures 

 scarcely any development occurs along the line of puncture ; upon the sur- 

 face a shining, orange-colored layer is formed. Upon agar a similar devel- 

 opment occurs. Upon potato the growth is limited to the line of inoculation 

 and is of shining, oimtge-red color. 



239. BACILLUS BRUNNEUS (Adametz). 



Found in water. 



Morphology. Small, slender bacilli. 



Biological Characters. An. aerobic and facultative anaerobic, non- 

 liquefying, non-motile bacillus. Forms a brown pigment. Forms spores. 

 Grows in the usual culture media at the room temperature. Upon gelatin 

 plates the superficial colonies appear as little drops of slimy consistence, but 

 not viscid ; under a low power they are at first white and opaque, with circu- 

 lar contour ; later, in ten to fourteen days, they are gray, and a brown color 

 is given off from the lower surface. In gelatin stick cultures development 



