SEVENTH ANNUAL MEETING 97 



have survived its period of usefulness before it is ever em- 

 ployed. 



The City of Evanston believes she has solved her water sup- 

 ply problem, with the completion in June of the new $225,000 

 filtration plant. Meantime, the city water is rendered safe by 

 chemical sterilization. The steps that have led to these results 

 may not be without interest and a certain moral. 



It has been obvious to many for a number of years that the 

 local water supply carries sewage contamination. A mere 

 physical survey of the situation makes this probable. From 

 the south line of the City of Evanston to the north line of the 

 City of Glencoe, thirteen main sewers pour the drainage of a 

 population of 40,000 into Lake Michigan. The Evanston 

 intake lies in 35 feet of water one and a sixteenth miles from 

 the shore. Knowing that typhoid bacilli can live from one day 

 to a week in lake water and with capricious currents at play, a 

 vicious circle is most possible. Chemical and bacteriological 

 tests repeatedly confirm this. Furthermore, before the chem- 

 ical sterilization of the water, Evanston, with about the same 

 sources of food and milk supply as Chicago, with superior 

 sanitary advantages and a select population, maintained for a 

 number of years a typhoid death rate from two to three times 

 that of Chicago. 



COMPARISON OF DEATH RATES FROM TYPHOID PER 100,000 IN 

 EVANSTON AND CHICAGO 



An investigation of a hundred Evanston cases in 1911 

 showed that 90 per cent of the victims were users of raw city 

 water. The distribution of these cases by months showed a 

 larger number of cases in the winter months. In sanitary sci- 

 ence, this is a recognized index of water-borne typhoid. The 

 situation became acute when in November and December, 

 1911, Evanston, with a population of 30,000, was averaging 

 over a case a day. 



At a cost of $750.00, and on short notice, a "Hypo" steril- 

 ization plant was installed, December 25th, 1911, at the Pump- 

 ing Station, and within two weeks, the mild epidemic was 

 checked. Since that time the rate has been maintained near 



