VIBRIO OR CHOLERA SPIRILLUM GROUP 371 



guinea-pig results fatally. Ingest ion of the organisms by young 

 rabbits may result in the development of the symptoms and lesions 

 of typical cholera as they are observed in man. 



Character of Disease and Lesions in Man. Asiatic cholera is 

 characterized by a severe diarrhea. The intestinal epithelium 

 is desquamated, and gives rise to the appearance known as " rice- 

 water " stools. The intestinal tract shows congestion and some- 

 times extensive, even diphtheritic, necrosis. The loss of water 

 from the blood results in a considerable, frequently fatal, diminu- 

 tion in blood-pressure. 



Immunity. True toxins have been demonstrated for the 

 cholera spirillum. They are produced under peculiar cultural 

 conditions. Antitoxin has also been produced. Agglutinins and 

 precipitins are found in immune blood, and frequently in the blood 

 of patients. Bacteriolysins may be readily demonstrated; in 

 fact, it is with this organism that the classic demonstration of 

 Pfeiffer's phenomenon was carried out. 



Active immunization against Asiatic cholera has been exten- 

 sively practised. The vaccine consists either of cultures killed 

 at 58 or of cultures attenuated by growth at 39. 



Bacteriological Diagnosis. This may be accomplished by 

 an examination of a stained mount from the rice-water discharges, 

 by isolation of the organism, or by the agglutination test. 



Transmission. The disease is transmitted through impure 

 water and food, particularly vegetables, contaminated with the 

 excretions of cholera patients. 



Non-pathogenic Spirilla 



Many species of spirilla closely resembling the preceding in 

 morphology and cultural characters, but lacking in pathogenicity, 

 have been isolated from a variety of sources. Such are the 

 Vibrio proteus or Spirillum of Finkler and Prior, isolated from the 

 stools in a case of cholera nostras, Spirillum tyrogenum, or Deneke's 

 spirillum from cheese, Spirillum phosphorescens, isolated from 

 water, and many others. 



