BACILLI OF THE COLON. 65 



bowel do occur because; hemorrhage sometimes occurs 

 in paratyphoid fever. 



Immunity follows an attack of paratyphoid fever 

 just as in true typhoid, but the protection is only 

 against the type of paratyphoid bacillus causing the 

 infection. A case illustrating this point came under 

 the writer's observation in the summer of 1913, in 

 which the patient developed typhoid-like symptoms 

 and fever, although he had had a severe typhoid in- 

 fection only a few years before. The infection proved 

 to be a paratyphoid type B. 



In the immunization against typhoid with killed 

 cultures it is now customary to use the killed bacilli 

 of both typhoid and paratyphoid in order to> confer 

 immunity to all types of typhoid-like organisms. 



THE BACILLI OF THE DYSENTERY GROUP. 



The first member of this group was discovered by 

 Shiga, a Japanese, in 1897. In its size and shape it 

 is very much like the colon bacillus, but does not fer- 

 ment sugars like the colon bacillus does. It can be 

 grown from the surface of the large bowel or from 

 the stools of dysenteric patients, and cultures when 

 fed to dogs cause dysentery. 



In man the dysentery bacilli will give rise to 

 severe diarrhea, accompanied with cramps, tenesmus, 

 and fever. The stools are streaked with blood and 

 contain mucus. The disease spreads rapidly, some- 

 times through infected water, sometimes from direct 



