70 
BACTERIOLOGY. 
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 
contact. It lasts from seven to ten days, and fre¬ 
quently is attended with a death rate of from 5 to 20 
in 100. 
Numerous epidemics have been reported in the 
United States; among them an epidemic of 350 cases in 
the village of Tuckahoe, N. Y., which was studied by 
the writer, together with Dr. Wm. H. Park. The 
cause of the epidemic was found to be due to an organ¬ 
ism almost identical with the one described by Shiga. 
From a study of the dysentery bacilli found in this and 
