476 INFECTION AND IMMUNITY. 



intestinal epithelium, as a consequence of which 

 rapid absorption of the toxin from the intestinal 

 canal takes place through the denuded surface. 

 This theory supposes that the toxin is not readily 

 absorbed through the intact epithelium. The liv- 

 ing vibrio has never been cultivated from the 

 blood. 



The changes in the intestines depend on the 

 duration of the infection. In cases which prove 

 fatal within a few hours the mucosa shows only 

 moderate general reddening, which is intensified 

 at the borders of Peyer's patches and the solitary 

 follicles. The intestinal contents are of a rather 

 clear fluid nature in which are suspended flakes of 

 mucus and epithelium; the fluid may be tinged 

 with blood. With a longer duration the destructive 

 processes in the mucosa become more intense, and 

 consist largely of desquamation of the superficial 

 epithelium and intense congestion of the denuded 

 submucosa. In the more prolonged cases, "chol- 

 era-typhoid," the mucosa, especially above the ileo- 

 cecal valve, may show diphtheritic necrosis. The 

 serous surface of the intestines is injected. 

 Prophylaxis. The rational prophylaxis founded by Koch, on 

 a knowledge of the biologic characteristics of the 

 comma bacillus, has proved of great efficiency. 

 The essential points are the following: 1. Imme- 

 diate bacteriologic examination of the stools in 

 suspicious cases. 2. Absolute isolation of patients, 

 in a hospital whenever possible. 3. Thorough dis- 

 infection of the stools, linen, room and all articles 

 with which the patient has been in contact, includ- 

 ing water-closets and privies. 4. Continued iso- 

 lation during convalescence until the stools are 

 free from vibrios. 5. Eepeated bacteriologic ex- 



