BY R. GKEIG SMITH. 



459 



separates it from the coli type of Bac. aureus and Bac. subflavus, 

 Zimmermann. Its nearest ally appears to be Zimmermann's 

 organism, of which it is probably a variety. 



Bacterium arborescens amethystinum, n.subsp. 



Shape, etc. — It is a very thin rod with rounded ends, and 

 measures 0-2-0-3 : 1-5-23 /u. It is not motile and is not stained 

 by Gram's method. Threads are formed in bouillon. No spores 

 were observed. It grows best at 22° and 30°; there is little 

 growth at 37°. 



Agar plate. — The colonies are thin and diffused, of a blue white 

 colour and translucent. When magnified sixty-fold, the centre 

 is seen to be granular and the margin indefinite with watery 

 transparent processes extending outwards. The deep colonies are 

 rounded or oval, and slightly moruloid. 



Agar slope. — A translucent, moist glistening, white growth, 

 with a decided violet tinge. The margin is indefinite and sends 

 off watery irregular processes which have a greenish colour. The 

 growth is luxuriant and soon spreads to the sides of the tube. 

 The condensed water becomes pinkish-cream coloured. 



Gelatine plate. — -The colonies appear like delicate moulds. 

 When magnified the structure is seen to be mycelioid or root-like. 

 There are prominent thick main trunks, and between these 

 delicate radial threads fill up the spaces and give the colonies a 

 circular shape. 



Gelatine stab. — The growth is fusiform and a cloudiness radiates 

 from the top of the canal into the medium; when magnified 10 

 times, delicate hairs are suggested. The cloudiness hangs down- 

 wards as a veil from the margin of the buff-coloured sunken 

 nail-head. Liquefaction slowly takes place at first in a strati- 

 form, then a funicular manner. There is formed an orange- 

 coloured film and a precipitate which changes from white to 

 orange. 



Glucose-gelatine. — There is no gas produced. 



Bouillon. — The medium becomes uniformly turbid and there is 

 formed a whitish precipitate. The indol reaction is decided. 



