PATHOGENIC BACTERIA. 32 1 



nomenon, and is the underlying principle of aU agglutination 

 reactions, such as the Gruber-Widal typhoid test. 



It seems probable, from the results so far obtained, that it is practicable to 

 use injections of attenuated cultures upon human beings with safety, and in 

 this way to protect healthy persons from cholera during an epidemic* 



Although a positive demonstration that the spirillum of 

 Koch is the cause of cholera is lacking, as far as the exact 

 reproduction of the disease in animals is concerned, the neces- 

 sary proof has been suppHed by the accidental or intentional 

 infection of laboratory investigators who were working with 

 cholera, which has happened on several occasions. 



Bacteriological investigations have shown that the spirilla of 

 cholera are present in very large numbers in the watery contents 

 of the intestine, especially early in the disease. They appear 

 in the lumina of the glands, and they may be seen underneath 

 the epithelial cells. They may occur in the matters vomited. 

 They usually are not found widely spread through the organs 

 of the body. It is probable that the symptords of the disease 

 result from poisonous substances produced by the spirilla or 

 contained in them. 



The portal of entry in cholera is probably always the aU- 

 mentary tract, and the infectious agent is usually, though not 

 always, transmitted through drinking-water, and numerous 

 epidemics have been traced to this source. In some cases the 

 origin of the contamination of the water with cholera dejecta 

 has been demonstrated. The organism may, however, be 

 introduced into the alimentary tract upon any and every article 

 of food. It may be conveyed from place to place upon soiled 

 clothing and bedding, and then be brought in contact with 

 food. FHes also probably convey the organisms from cholera 

 stools to articles of food. In order to combat the spread of 

 the disease the excreta and bedding should be thoroughly 



* Strong. American Medicine. August 15, 1903. 



