QUALITATIVE BACTERIOLOGICAL ANALYSIS. 131 



margin, and often there is a slight knob in the centre of the 

 colony. Under a low power they appear round, finely granular, 

 with a dark centre ; the colour is yellow in the centre, and 

 clear grey at the margin. The gelatine around the colonies 

 acquires a green colour. 



Gelatine-stab. Surface growth is white and opaque ; along 

 the stab there is also a delicate white growth. The gelatine 

 assumes a bright green colour. 



Agar. A thick white growth; the agar acquires a green 

 colour. 



Glucose-gelatine (shake). No gas formation. 

 Peptone and Salt Solution. No indol reaction obtained. 

 Broth. Diffuse growth ; after several days a pellicle appears 

 on the surface. The broth acquires a green colour. 

 Nitrate-broth. No reduction of nitrates. 



Potato. At first there is a greenish-yellow growth, which 

 later forms a brownish, slimy expansion. 

 Milk. Unchanged. 



Microscopical Appearance. A small motile bacillus with 

 rounded ends, often in pairs. It grows best at room temperature, 

 and does not form spores. 



In my experience this organism is often found in polluted 

 waters. Some of the varieties isolated, when sub-cultured in 

 broth, produced pathogenic effects when 1 c.c. was injected 

 sub-cutaneously into guinea-pigs. Lepierre isolated a similar 

 organism from a cistern at Coimbra, but the bacillus was not 

 motile. 



Bacillus Erythrosporus. 



This micro-organism was isolated from putrefying liquids 

 by Eidam ; it has also been found in water by Bolton and 

 Migula. 



Gelatine Plates. The surface colonies form white centres, 

 with a slightly irregular margin. Under a low power the centre 

 is dark brown in colour ; the margin shows radial streation, 

 and has a yellowish-green colour. The gelatine is not liquefied, 

 and around each colony acquires a green fluorescence. 



Gelatine-stab. There is a white growth along the stab and on 

 the surface ; the gelatine acquires a green colour. 



