BACILLI 473 



1 



BACILLUS BEROLINENSIS INDICUS ( ' Indigoblauer 



Bacillus ' ) 



Authority. Claessen, ' Ueber einen indigoblauen Farbstoff erzeugenden 

 Bacillus aus Wasser,' Centralblatt f. Bakteriologie, vol. vii., 1890, p. 13. 



"Where Found. Unfiltered river Spree water. 



Microscopic Appearance. Fine slender bacillus with rounded ends, much 

 resembling in its dimensions the typhoid bacillus. It occurs mostly singly, but 

 also in pairs and threes, and is sometimes found, especially in fresh cultures^ 

 lying together lengthwise in packets. The bacillus is surrounded by a delicate 

 -envelope of protoplasm, which is easily seen when it is mordanted and subse- 

 quently stained. It is very motile. No spore formation observed, although 

 bright and shining granules were noted in broth and potato cultures, but it was 

 not possible to stain them. 



Cultures. 



GELATINE PLATES. Forms pin-head colonies at first greyish white, but on 

 the fourth day the centre becomes indigo in colour. The colourless edge of the 

 surface colonies becomes irregular and recalls the appearance of typhoid colonies. 

 In the depth the rim of the colony first becomes tinted, whilst the centre 

 remains mostly greyish yellow in colour. No liquefaction takes place. 



GELATINE TUBES. At the point of inoculation after twenty-four hours a 

 spot of deep indigo blue is seen, which increases in size, spreading gradually 

 with irregular contour over the surface. The colour does not penetrate into the 

 gelatine. 



AGAR-AGAK. Produces a thick moist and shining expansion of a deep indigo 

 blue. 



POTATOES. On acid potatoes it produces a deep blue expansion, on alkaline 

 potatoes it gives rise to a thin moist and shining dirty green growth. 



BROTH. Renders it turbid, and flocculent particles pervade the liquid. No 

 colour is produced. 



DISTILLED WATER. Culture material containing the bacillus when inoculated 

 into 1 c.c. of sterilised distilled water induced in the latter a distinctly milky 

 turbidity in twenty-four hours. 



Remarks. It is strictly aerobic. The production of pigment takes place also 

 when the cultures are kept in the dark. It flourishes better at about 15 C. than at 

 higher temperatures. 



