126 THE ACUTE SELF-LIMITED INFECTIONS 



mucous membrane of the lower part of the small 

 intestine. This they penetrate only as far as the 

 deeper layers of the innermost coat of the tube, and 

 by their growth cause a shedding of the coat. The 

 shreds of the desquamated mucous membrane pass off 

 with the watery discharges, and cause the characteristic 

 "rice water" stools. The bared and congested surface 

 permits absorption of the poisons of the spirillum, the 

 body of which does not itself enter the blood stream. 

 The poison quite frequently has a depressing action 

 upon the heart muscle. It is not quite certain whether 

 or not this is a wholly extracellular toxin or combined 

 closely with the bacterial bodies. It is probably mostly 

 of the latter character, an endotoxin separated upon 

 the disintegration of the germ cells. 



Cholera is a disease transmitted almost exclusively 

 by polluted water, although food infected with bacteria 

 may, of course, transmit it. Water is contaminated by 

 dejecta of cholera patients, and the vibrio leaves the 

 patient in no way but with feces (or vomiting of intes- 

 tinal contents, a rare occurrence). Large numbers of 

 vibrios are present in the feces early in the attack. Later 

 they rapidly decrease, but do not disappear from the 

 gut and feces, and may continue to come away in small 

 numbers for many months. In such cases they natur- 

 ally pollute anything with which the dejecta come in 

 contact. They do not live long in nature, however, and 

 regulations can be made to kill them. Flies having 

 soiled themselves upon cholera excreta may carry the 

 germs. Vegetables may be soiled from water. Personal 

 contact and handling of clothes from patients have the 

 same value in transmission of cholera as for typhoid 



