QUALITATIVE BACTERIOLOGICAL ANALYSIS. 55 



Stab-gelatine. The gelatine is rapidly liquefied in the form of 

 a funnel. 



Glucose-gelatine. There is no gas formation. 



Milk. Remains unchanged. 



Broth. There is a diffuse growth, and an abundant deposit at 

 the bottom of the tube. 



Nitrate-broth. Nitrates are reduced to nitrites and ammonia. 



Potato. The growth on potato varies ; sometimes it has a 

 light yellow colour, at other times it has a flesh-coloured tint 

 changing to reddish-brown. 



Peptone-water. No indol reaction is obtained. 



Agar -slope. A white expansion. 



Microscopical Appearance. A short motile bacillus, often in 

 pairs. It does not form spores. It does not grow well at 37 C. 



The B. liquefaciens of Eisenberg corresponds to the above 

 type, but does not grow at 37 C. The B. liquidus, described by 

 the Franklands, forms large cup-shaped depressions, and pro- 

 duces a thick, moist, flesh-coloured growth on potato. 



The B. punctatus of Zimmermann forms cup-shaped liquefying 

 colonies ; in the bluish-grey liquid whitish dotted groups of 

 bacteria occur, which frequently appear joined to one another by 

 white streaks. In stab-gelatine the gelatine is liquefied in the 

 form of a stocking. On potato there is a brownish flesh-coloured 

 expansion. It grows better at 30 C. than at the ordinary 

 temperature. 



The B. aquatilis communis is said by Fliigge to be one of the 

 commonest organisms in river- water and well-water, and probably 

 identical with the B. punctatus and B. liquidus. It is a plump, 

 medium sized very motile bacillus. It does not form spores and 

 it is not stained by Gram's method. It liquefies gelatine very 

 rapidly, and in forty-eight hours a stocking-shaped liquefaction 

 is produced. The colonies in the depth are round plates, and 

 on the surface form round cups which are filled with masses of 

 bacteria without any special arrangement ; the margin is finely 

 granular but not rayed. On agar at 37 C. it produces a trans- 

 parent grey expansion. On potato it produces a yellowish- 

 brown or reddish growth. The B. liquefaciens communis of 

 Sternberg is found in faeces ; it resembles the B. aquatilis com- 

 munis both morphologically and in cultures. 



