98 ILLINOIS ACADEMY OF SCIENCE 



the normal residual typhoid rate for this district. Moreover, 

 our cases now occur mostly in the summer and autumn, the 

 period when vacation typhoid, finger and fly typhoid, etc., are 

 operative. This is borne out by the following chart : 



TYPHOID CASES BY THE MONTH EVANSTON 



Total Total 



Year Jan. Feb. Mch. Apr. May June July Aug. Sept Oct. Nov, Dec. Cases Deaths 



1910 .7 8 19 454453320 69 6 



1911 41 1030424 9 22 49 99 7 



1912 12 9 2412105 17 7 4 64 4 



1913 0111342168 3 30 4 



Year Cases per 100,000 Deaths per 100,000 



1910 276 24 



1911 396 28 



1912 224 13.8 



1913 100 13.3 



Enteritis is recognized as a disease rather closely associated 

 with a contaminated water supply. The following table sum- 

 marizes the deaths from this cause for the past seven years. 



EVANSTON DEATH RATE PER 100,000 



Disease 1907 1908 1909 1910 1911 1912 1913 



Enteritis 45 20 52 48 32 12 37 



While there is a notable falling off in 1912, there is a return 

 to near former rate from this disease in 1913. This is possibly 

 explained by the fact of a higher mortality rate, especially 

 among infants during the unusually hot summer of 1913. A 

 higher rate with a greater percentage of cases among young 

 children would in itself rather point to food supply as a source 

 of the infection. 



It is fully recognized that too much reliance cannot be 

 placed upon statistics gathered from a population of 30,000 

 people, yet a fair examination of all the data seems to confirm 

 the experience of many large cities in respect to water borne 

 diseases before and after improvement in the water supply. 



If Hazen's theorem is correct, namely, that for every death 

 from water borne typhoid, there are three or four deaths from 

 other diseases attributable also to contaminated water, the 

 above improvement in the typhoid rate has still greater sig- 

 nificance to the community. 



Recognizing the conclusive evidence of sewage contamina- 

 tion of the city water, a bond issue for $200,000 was voted by a 

 large poll in the fall of 1912. 



This plant, now near completion, is of the mechanical grav- 

 ity type equipped with mixing tank, settling basins, six inde- 

 pendent two million gallon filter units and two \% million 



