BACTERIA IN DIPHTHERIA. 369 



Biological Characters. An aerobic, non-liquefying (non-motile ?) ba- 

 cillus. Upon gelatin plates semi-transparent, grayish colonies are formed, 

 which later have a brownish color; the surface of these is finely granular 

 and of a pearly lustre. In stick cultures in nutrient gelatin the growth 

 along the line of puncture is very scanty. On potato a flat, whitish layer is 

 formed, which extends slowty over the surface. Grows best at a temperature 

 of 30 to 35 C. 



Pathogenesis. Pure cultures injected into the peritoneal cavity or sub- 

 cutaneously in rabbits caused the death of these animals in from three to 

 fourteen days, according to the quantity injected. At the autopsy necrotic 

 foci are found in the liver and spleen, and the mesenteric glands are en- 

 larged, but the intestine presents a healthy appearance. But when cultures 

 are introduced into the alimentary canal the characteristic diphtheritic in- 

 flammation of the mucous membrane of the intestine is induced. This re- 

 sult was obtained both by direct injection into the lumen of the intestine 

 and by injecting cultures into the mouth. 



