112 BACTERIOLOGY FOR NURSES 



be attributed to the bacillus of typhoid. Mixed 

 infections also are not uncommon, the pus cocci and 

 the pneumococci frequently causing serious or fatal 

 complications. 



Modes of Dissemination. — Typhoid fever may be 

 disseminated by polluted water, food, and soil, each 

 factor carrying the bacilH in an infinite number of 

 ways, which are often so circuitous that to the igno- 

 rant they seem to be very "far-fetched." Air-borne 

 infection is rare. 



Water pollution in cities and towns is always the 

 result of a close relation between the water supply 

 and the disposal of sewage; the same statement 

 holds good in villages and farms where the water 

 comes from shallow wells in close proximity to privy 

 vaults. For twenty years, ending about 1893, 

 typhoid fever prevailed to an alarming extent in 

 Chicago, where the city sewage was discharged into 

 Lake Michigan and the city water was drawn from 

 the same source from intakes at one half and one 

 mile from shore. The prevalence culminated in a 

 severe epidemic in 1892, when in Cook County Hospi- 

 tal alone there were two hundred and forty typhoid- 

 fever patients on August 1. 



During the following year a new three-mile intake 

 was opened, and soon after the drainage canal which 



