EXERCISE 61 

 WHAT IS THE RELATION BETWEEN WATER SUPPLY AND DISEASE? 



Materials. Data given in Figs. 79, 81, and 82 in the " Elements of General Science " ; any 

 additional similar data which are available. 



Directions. The above question may be answered by study of the death rate from typhoid fever 

 in relation to the character of water supply. 



Examine Figs. 79, 81, and 82 in the textbook. Explain in full to what extent typhoid appears 

 to be a controllable disease and how far proper water supply may assist in controlling it. Give the 

 facts on which you base your opinion. 



Additional problems. How do the leading American and European cities compare relative to propor- 

 tionate deaths from typhoid ? How may any difference be explained ? 

 Are rivers likely to be the best sources of water supply? 



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