BACILLI OF THE COLON. 
63 
fed the city reservoir; 1500 cases of typhoid occurred 
in a remarkably short time. 
Wells are sometimes infected from privies, cis¬ 
terns, and open cesspools when they are placed near a 
well, or when the natural drainage of the soil-water is 
in the direction o-f the well. Defective walls or cover¬ 
ing that admit surface-water render the infection of 
wells in this way more likely. 
Milk is -an excellent culture medium, and typhoid 
bacilli will grow readily in it. They gain entrance to 
the milk by washing the milk cans or pails in infected 
water, or from the hands of persons sick or but 
recently recovered from the disease. Flies may also 
carry the infection to milk. There have been some 
185 epidemics of typhoid traced to milk. In 1903 a 
milkman in Boston sick with typhoid spread the dis¬ 
ease through the milk, causing an epidemic of. over 
400 cases. 
The infection may be spread by eating uncooked 
vegetables that have been washed in infected water. 
Oysters and clams, when they have been grown in 
water contaminated with sewage, have been known to 
carry the infection. Along the seaboard laws are now 
in force that prohibit the cultivation of oysters in 
water near the outlet of sewers. The importance of 
flies in the spread of typhoid has been recognized only 
in the last ten years. When they come in contact with 
typhoid patients, or with infected discharges, they 
carry the bacilli on their bodies and deposit them on 
foodstuffs. 
