QUALITATIVE BACTERIOLOGICAL ANALYSIS. 73 



brown in colour ; along the line of inoculation there is also a 

 brown growth. 



B. Fuscus. 



Found by Zimmermann in the Chemnitz water supply. It 

 is a thin non-motile bacillus which varies considerably in length. 

 Sometimes the rods are bent ; no spore formation has been 

 observed. It is aerobic and grows best at 30 C. In gelatine 

 plates the deep colonies appear as small brown granular dots ; 

 on the surface the colonies form pin-heads, which later become 

 surrounded by a thinner margin, which is often thrown into 

 folds. The centre of the colony has a dark brown colour ; the 

 gelatine is not liquefied. In gelatine-stab it produces a project- 

 ing growth, which later expands and acquires a chrome-yellow 

 colour. On agar and potato the same chrome-yellow growth is 

 produced. 



B. Fuscus Limbatus. 



Isolated by Scheibenzuber from bad eggs ; also found by 

 Tataroff in water. It is a short motile bacillus, which often 

 forms threads. The colonies in gelatine are brownish lumps ; 

 some of them are surrounded by a lighter zone, two or three 

 times as wide as the original colony; the gelatine is not 

 liquefied. 



In gelatine-stab there is very little growth on the surface ; 

 along the line of inoculation there is a growth from which buds 

 spread out horizontally; the gelatine in the neighbourhood is 

 coloured brown. On agar there is a superficial expansion, and 

 the medium becomes coloured brown. On potato it produces a 

 brown growth. 



B. Hydrophilus Fuscus. 



This organism was discovered by Sanarelli in a well-water of 

 the University of Siena. It is pathogenic for frogs and other 

 animals. It is a thin, very motile bacillus of variable length. 

 It does not form spores and is not stained by Gram ; grow r s best 

 at 37 C. In gelatine plates the colonies are round and 

 transparent ; the gelatine is rapidly liquefied. In gelatine-stab 

 the gelatine is rapidly liquefied in the form of a funnel ; in a 

 very short time the whole of the tube is liquefied, and there is 



