58 BACTERIOLOGY. 



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 

 frequently occur. The persistence of the typhoid 

 bacilli in the bile is an important factor in the produc- 

 tion 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 

 organism with twelve or more flagella, and actively 

 motile. It grows on all the ordinary culture media in 

 the presence or absence of oxygen. 



infectkm Infection with typhoid bacilli always occurs by 



place wav f tne 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, 

 typhoid 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 

 infected 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 

 laborers' camp situated on the banks of the stream that 



