62 
BACTERIOLOGY. 
The way 
infection 
takes 
place 
of the organs and tissues of the body. In the bile, 
urine, and stools the bacilli may persist for months and 
years after the acute infection has passed. It is for 
this reason that complications and sequelae so fre¬ 
quently occur. The persistence of the typhoid bacilli 
in the bile is an important factor in the production of 
gall-stones; the bacilli have been found in the centers 
of stones from ten to fifteen years after the infection. 
The typhoid bacillus is a short, rod-shaped organ¬ 
ism with twelve or more flagella, and actively motile. 
It grows on all the ordinary culture media in the pres¬ 
ence or absence of oxygen. The colonies on agar re¬ 
semble grape-vine leaves. It is Gram negative. 
Infection with typhoid bacilli always occurs by 
way of the alimentary tract, by infected water or food. 
Added to the cause of infection there is usually a 
lowered resistance on the part of the individual. 
The infection reaches the alimentary tract, most 
often through infected water. As we have seen, ty¬ 
phoid bacilli will live for months in the soil; so that 
the discharges from typhoid patients that have not 
been disinfected and are deposited in or on the ground 
may lead to the infection of nearby wells and streams 
particularly during periods of heavy rain. Water in¬ 
fected in this way may give rise to local epidemics in 
the case of wells, or to epidemics miles away in the 
case of streams. The epidemic of typhoid fever in 
Ithaca, N. Y., in 1903 was caused by the infection of 
the city water supply by a case of typhoid in a laborer’s 
camp situated on the banks of the stream that 
