BY R. GREIG SMITH. 445 



oon becomes shallow crateriform. There is practically no growth 

 in the depth of the medium, and a primrose-coloured film lies on 

 the liquefied gelatine. There is no gas developed from glucose, 

 and milk is coagulated, the reaction being neutral. On potato 

 the growth is canary-coloured, but changes to a pale yellow; it is 

 raised and irregularly spread. Nitrates are not reduced. In 

 bouillon a turbidity is formed; there is a precipitate, but no film. 

 A strong indol reaction was obtained. 



Bacterium arrorescens. 



Bacillus arborescens, Frankland. 



On gelatine the colonies are pale yellow and circular, with a 

 slight mycelioid appearance. The medium is liquefied round the 

 colony. When magnified the deep colonies are seen to have an 

 irregular centre, from which root-like fibres extend ; these are 

 closely packed together and yellowish. The surface colonies have 

 an indefinite centre, from which loosely twisted and sharply bent 

 comparatively wide strands apparently anastomose. The stab in 

 gelatine is filiform, with a smooth, moist glistening, deep yellow 

 nail-head. The gelatine is slowly liquefied in a crateriform 

 manner, and just below the liquefied medium the filiform stab 

 becomes expanded and diffuse. The colonies on agar are circular, 

 raised, moist glistening and of a translucent pale buff colour. 

 When magnified they are seen to have a granular centre, with a 

 transparent irregular margin, beset with short irregular processes. 

 The deep colonies are rounded, oval or lenticular and rough. 

 The agar stroke is moist glistening, raised and spreading. The 

 colour is a deep yellow which changes, especially in the centre of 

 the growth, to old-gold. No gas is formed in glucose-gelatine, 

 and nitrate is not reduced. Bouillon becomes turbid, and there 

 is a filamentous precipitate, but no film. A slight indol reaction 

 was obtained. Milk is not coagulated. On potato the growth 

 is flat, spreading, glistening and deep yellow in colour. The 

 organisms are rods with rounded ends, and may be long or short; 

 the average size is 0*3 : 2 p. 



