BACILLUS MEMBBAXACEUS AMETHYSTINUS 137 



in thrust-cultures. The fourth form does not grow on 

 potato. 



Bacillus aquatilis radiatus. — Zimmermann found this 

 bacillus in the water of the Chemnitz water-works. The 

 rods are motile and form irregular colonies on the gelatine 

 plate, with root-like processes arranged in a radiating 

 manner. The gelatine is liquefied with tolerable rapidity, 

 and the mass of bacteria is collected in the centre of the 

 fluid colony, while all round it extends a yellowish-coloured 

 ring which is environed by a cloudy yellowish mass. Thrust- 

 cultures show a circular pellicle on the surface when lique- 

 faction has taken place. A layer forms on agar which 

 appears bluish by direct, yellowish by transmitted light. 



Bacterium Ziirnianum, described by Adametz, displays 

 short, immotile rods. The colonies, which do not liquefy 

 gelatine, form masses like clusters of grapes, and the surface 

 of thrust-cultures has also a similar appearance. It grows 

 on potatoes at 25° to 30° C. 



Bacillus membranaceus amethystinus. — Eisenberg and 

 Jolles have discovered this bacillus in the sjDring-water of 

 Spalato. It has the power of liquefying gelatine with de- 

 velopment of a dark violet pigment, and its rods are short 

 and immotile. Small, dark violet colonies develop on 

 gelatine plates and liquefy slowly, while a violet pellicle 

 appears on the surface of the liquefied mass, resembling a 

 membrane stained with gentian violet. A deposit with 

 serrated edges develops on thrust-cultures and acquires a 

 violet colour in about a fortnight, slowly liquefying the 

 gelatine. The liquid mass is covered with a violet pellicle 

 in this case also. A whitish layer, which later becomes 

 violet, forms upon agar ; the deposit on potato is of a 

 dirty oHve-green, while a violet sediment and a violet pellicle 

 develop in bouillon. 



Bacillus indigoferus. — The bacillus of this name, detected 



