Even with the deflection of the Chicago River, causing it to flow into the Mississippi instead of Lake Michigan, the Chicago water is not entirely safe. Especially is it found that after heavy storms the deposits which have settled for many years on the bottom of the lake are stirred and the water becomes turbid and impure. The Board of Trustees of the sanitary district of Chicago recently summarized the condition of the water as follows:

"The general quality of the Chicago city water supply during

1 Lancet, 1908, Volume 174, page 1024 the last few months of 1913 was good. Only storms of unusual severity agitated the bottom of the lake sufficiently to cause the water to appear turbid. The slight increase of the Chicago death rate of 1913 over that of 1912 was not due to the water supply." In a statement made to me by the Department of Health of the city of Chicago, on January 8th, 1916, the following information is given as to the methods of purifying the Chicago drinking water, and also the quantity thereof consumed:

The water supply of Chicago is obtained from Lake Michigan by means of six crib intakes located from two to four miles from shore, along the water front. Two of these crib intakes, e.g., the extreme north and south cribs, which have in the past shown a slight amount of contamination, are being treated by means of chlorid of lime in a dosage of two-tenths part available chlorin per million. The water from the harbor intake, two mile crib, is now being treated by means of liquid chlorin in a dosage of two-tenths part per million.

The total pumpage during the year 1915, as given by the Department of Public Works, is 221,654,000,000 gallons. During the year 1916, to date, the average pumpage has been 630,000,000 gallons daily.