430 CHOLERA. 



ances, though it is rather thinner and smaller. Its growth 

 in gelatine is also somewhat similar, but liquefaction pro- 

 ceeds more rapidly, and the bell-shaped depression on the 

 surface is larger and shallower, whilst the growth has a 

 more distinctly yellowish tint. The colonies in plates also 

 show points of resemblance, though the youngest colonies 

 are rather smoother and more regular on the surface, and 

 liquefaction occurs more rapidly than in the case of the 

 cholera organism. The colonies have, on naked-eye ex- 

 amination, a distinctly yellowish colour. The organism 

 does not give the cholera-red reaction, and on potato it 

 forms a thin yellowish layer when incubated above 30 C. 

 When tested by intraperitoneal injection and by other 

 methods it is found to possess very feeble, or almost no, 

 pathogenic properties. Koch found that this organism, 

 when administered through the stomach in the same way 

 as the cholera organism, produced a fatal result in three 

 cases out of fifteen. Deneke's spirillum is usually regarded 

 as a comparatively harmless saprophyte. 



