QUALITATIVE BACTERIOLOGICAL ANALYSIS. 79 



granular growth along the stab. On agar and potato the same 

 yellow-ochre growth appears. 



The Vibrio flavus described by Weibel, only differs from the 

 above in that the colour produced is pale yellow instead of 

 yellow-ochre. The Vibrio flavescens, also described by Weibel, 

 is a variety of the Vibrio aureus ; the colour of the colonies is 

 dirty greenish-yellow. 



Spirillum Rubrum. 



Isolated by Esmarch, and also found in water by Adametz. It 

 is about twice as thick as Koch's Vibrio and in most cultures 

 forms from one to three spirals ; in broth, however, it may form 

 twenty to fifty spiral turns. Spore formation is doubtful. 



In gelatine plates the colonies grow extremely slowly ; in about 

 eight days small red centres are seen, which, under a low power, 

 appear granular with a smooth margin ; gradually the colonies 

 assume a wine-red tint ; the gelatine is not liquefied. In gelatine- 

 stab there is a growth along the stab consisting of wine-red 

 colonies ; on the surface there is no colour produced. On agar it 

 produces a greyish-white growth, which is red in the thickest 

 part of the growth. On potato it forms small, deep red colonies. 

 It renders broth slightly turbid, and a red, deposit appears at the 

 bottom of the tube. 



Spirillum Rugula. 



Found by Miiller in the buccal cavity; also isolated from 

 stagnant water and faeces. It is often found with the B. butyricus 

 and is probably anaerobic. It forms long rods, which are some- 

 times thin and sometimes very thick ; it may be simply bent or 

 form flat spiral turns ; at times it forms long chains. It has a 

 lively rotatory movement on its long axis. It forms spores at 

 one end of the bacillus and just before the appearance of the 

 spore a swelling is formed, giving the bacillus a comma-like 

 form. In gelatine plates, under anaerobic conditions, it forms 

 yellowish-white, ball-shaped discs ; the gelatine is liquefied. In 

 gelatine-stab it forms a pin-head growth. On agar at 37 C. it 

 forms a white, slightly-folded growth. On potato at 37 C. it 

 forms a wrinkled growth, which later becomes yellow in colour. 



