46 BACTERIOLOGICAL EXAMINATION OF WATER. 



Microscopical Appearance. Short and long bacilli observed ; 

 the short forms are motile but the long ones are stationary. 

 Unstained spots appear in the rod, but they are probably not 

 spores. It grows best at room-temperature, and produces a 

 greyish-yellow pigment. A culture of this organism from 

 Krai's laboratory produced colonies closely resembling the 

 B. fluorescens non-liquefaciens. Its cultural reactions in the 

 various media also were identical with those of the latter 

 organism. The colour of the media, however, was more 

 yellowish in the case of the longus. The bacilli stained with 

 Gram. 



B. Fluorescens Tennis. 



This micro-organism was isolated by Zimmermann from 

 the Chemnitz water supply. It has the following biological 

 characteristics. 



Colonies on Gelatine Plates. The surface colonies are thin, 

 irregularly round with a denticulated edge ; the surrounding 

 gelatine acquires a green colour, and is not liquefied. 



Gelatine-stab. A thin greyish-white expansion appears on 

 the surface, which in about four days reaches the margin of 

 the tube. The stab is clearly defined, but no further growth 

 takes place. 



Gelatine-streak. After three days a leaf-like expansion is 

 produced. 



Agar-slope. A greyish growth is produced; the agar assumes 

 a green colour. 



Potato. A thin, greyish-yellow, smooth layer is produced, 

 which only after some time grows out from the line of inocu- 

 lation. Later, the colour of the growth becomes reddish- 

 brown. 



Gas-production. Not observed. 



Microscopical Appearance. Short thick bacilli with rounded 

 ends, often arranged in groups ; in old cultures the rod consists 

 of five or six links. It has only rotatory movement and is de- 

 colorised by Gramas method. 



A culture from Krai's laboratory produced very characteristic 

 colonies, which had the denticulated edge well marked. The 

 appearance of a surface colony strongly resembled a small shell. 



