24O BACTERIOLOGY. 



soluble in water, insoluble in ether and alcohol, un- 

 changed by alkalies, decolorised by acids. It is 

 similar to yellow aniline colours both spectro- 

 scopically and in ordinary reactions. 



Bacterium indicum (Micrococcus indicus, Koch. 

 Bacillus indicus, Fliigge). Very short rods with 

 rounded ends. In plate-cultivations on nutrient 

 agar-agar, the colonies have a scarlet tint. They 

 are round, ovoid, or spindle-shaped, and have 

 characteristic granular margins (Fig. 82). Grown 



i 



FIG. 82. BACTERIUM INDICUM ; COLONIES ON NUTRIENT 

 AGAR-AGAR, x 60. 



upon nutrient agar-agar in a test-tube, the appear- 

 ances are very characteristic. In a pure cultivation 

 a brilliant, vermilion-coloured reticulated pellicle 

 develops on the surface (Plate II., Fig. i). In the 

 track of the needle beneath the surface no pig- 

 ment is formed (Plate XIII., Fig. 2). Cultivated 

 in nutrient gelatine they liquefy the medium, and 

 colour it crimson. The growth, of a darker 

 crimson hue, subsides to the bottom of the tube. 

 Upon sterilised potato they form a vermilion layer 

 (Plate XV., Fig. 2). 



