QUALITATIVE BACTERIOLOGICAL ANALYSIS. 59 



B. Ruber Berolinensis. 



The red water bacillus of C. Friinkel is probably a modifica- 

 tion of the above, which it closely resembles in morphology and 

 cultures. The colour in gelatine is yellowish-red, on agar 

 yellow, and on potato rust-red or orange-yellow. 



B. Ruber Aquatilis. 



The red water bacillus of Lustig is a small motile bacillus, 

 two or three times as long as broad. It does not form spores, 

 but it is not killed by heating to 60 C. for twenty-four hours. 

 In the body of the rods fuchsia-red pigment granules are seen. It 

 forms colonies with a serrated margin ; the centre of each colony 

 has a raspberry-red colour. The gelatine is quickly liquefied and 

 the red colour extends in all directions. In gelatine-stab there is 

 a funnel-shaped liquefaction at the surface, in the centre of which 

 pigment is found. In the depth of the stab there is a growth 

 but no pigment formation. On agar, potato, and in broth 

 there is a growth and formation of a raspberry-red colour at 

 ordinary temperatures, but at 37 C. there is no pigment 

 formation. 



B. Carneus. 



This bacillus was isolated by Tils from the Freiburg water 

 supply. It is a slender, very motile bacillus and does not form 

 spores. On gelatine it forms white colonies which liquefy the 

 gelatine producing cup-shaped depressions. In gelatine-stab it 

 causes a funnel-shaped liquefaction, the lower part of which 

 becomes filled with pink-coloured masses. On potato it grows 

 slowly producing a dark flesh-coloured expansion. The same 

 organism is described by Zimmermann as the B. carnosus. 



B. Lactis Erythrogenes. 



Found by Hueppe in red-coloured milk and probably identical 

 with the B. rosa fluorescens, isolated by Tataroff from the 

 Dorpat water. It is a small bacillus which is not motile, and 

 does not form spores. Its colonies are round, greyish-yellow in 

 colour, and slowly liquefy the gelatine which round the colonies 

 acquires a reddish colour. In gelatine-stab it grows slowly, and 



