QUALITATIVE BACTERIOLOGICAL ANALYSIS. 97 



shape. Gelatine-stab culture shows on the surface a moist 

 shining convex growth, and along the line of inoculation a 

 yellowish-white thick band, with closely packed, small, round 

 extensions having thick button-shaped ends. On potato it 

 forms a thick, yellowish expansion, and on one occasion bubbles 

 of gas were seen in a culture four days old. It does riot 

 liquefy gelatine, and microscopically it appears as a short rod 

 with rounded ends. 



B. Neapolitanus. This organism was discovered by 

 Emmerich in the blood and organs of cholera patients in 

 Naples. Weisser found it in the normal stools of human 

 beings and in air. On the surface it forms thin round colonies, 

 yellow in the centre but whiter at the margin ; in the depth 

 the colonies are whetstone in shape, and have a yellowish- 

 brown colour. It does not liquefy gelatine. In gelatine-stab 

 culture it grows like B. typhosus. On potato it forms a 

 slimy, yellowish-brown layer. Gas production has not been 

 observed. Microscopically it is about the same size as 

 B. typhosus, but it is not motile. It does not form spores, 

 and is decolorised by Gram. 



Deeleman has described four coliform organisms, isolated from 

 urine and faeces, which are important from a diagnostic point 

 of view. The chief reactions of these organisms are as follows : 



B. Coloides Virescens. In gelatine plates the colonies, 

 under a low power, show a leaf-like picture, with irregular, 

 well-defined edges. On gelatine-streak there is a greyish-white 

 growth, which has a greenish iridescence ; the gelatine is not 

 liquefied. On agar plates there is a diffuse veil-like growth 

 without any markings, which later shows a feeble greenish 

 iridescence. On potato there is a yellow, slightly raised 

 growth, limited to the line of inoculation. In broth there is a 

 diffused growth with formation of a greenish iridescent 

 pellicle and a moderate deposit. It ferments grape-sugar, 

 cane-sugar, and milk-sugar. Milk is coagulated in twenty-four 

 hours. In 10 c.c. of litmus-whey, after ten days at 37 C., it 

 produces from 13'6 to 14*3 c.c. of N acid. It gives no indol 

 reaction. It is pathogenic for mice and guinea-pigs. It is not 

 stained by Gram's method, and microscopically appears as a 

 small motile bacillus. 



