QUALITATIVE BACTERIOLOGICAL ANALYSIS. 148 



Gelatine Plates. Minute colonies become visible in twenty- 

 four hours. In two days the surface colonies begin to liquefy, 

 and are circular, 2 to 2-|- mm. in diameter, and under the micro- 

 scope are seen to have a very delicate, transparent, irregular, 

 spreading margin not yet liquefied . The circular liquefied portion 

 is turbid, with a granular deposit in the centre, and shows slight 

 but distinct greenish fluorescence. On the third day the colonies 

 are 5 to 6 mm. in diameter, and partly fused with one 

 another; the whole plate being largely liquefied with bright 

 yellowish-green fluorescence, and having a sour, unpleasant smell. 



Gelatine-stab. Growth chiefly on the surface ; hardly any to 

 be seen along the depth of the track. Liquefaction begins at 

 the surface on the second day in a cone, extending some way 

 along the needle tract. It gradually spreads, chiefly at the 

 surface, till it reaches the wall of the tube in seven days. In 

 fourteen days the gelatine is liquefied from 10 to 12 mm. from 

 the surface, and spreads downwards in a horizontal plane. The 

 liquefied portion has a yellowish-green fluorescence. 



Agar. No growth at 37 C. At 20 C. whitish, semi-opaque 

 growth, with an irregular edge. The agar has a brilliant 

 yellowish-green fluorescence. 



Potato. A dirty brown layer, spreading from the line of 

 inoculation. 



Broth. Rapid growth causing dense turbidity. A thin 

 film forms on the surface, and the top layer of the broth 

 acquires a marked greenish fluorescence. 



Milk. No coagulation, but after four days the upper layer 

 becomes slightly yellowish and less opaque, owing to gradual 

 digestion. 



Gas-production. Not observed. Growth scanty away from 

 the surface. Oxygen seems necessary for the production of the 

 fluorescent pigment. 



Bacillus Pluorescens Stercoralis. 



Source. Homerton and Barking sewage. 



Form and Arrangement. Motile rods, almost twice as long 

 as broad, but of variable length. The breadth varies from 

 0*5 fj. to 0*7 jU, and the length from 0*8 to 1*6 fj. ; longer forms 

 rarely occur. Actively motile. 



