THE INFLUENCE OF URBAN AND RURAL ENVIRONMENT 367 



1900-1908 averaged 133 per 100,000 population. In the 

 period 1911-1915 the average rage was 15.9. For comparison, 

 Boston showed rates of 16.0 and 8.0 for the five year periods 

 before and after 19 10 without change in its fairly satis- 

 factory water supply. 



At Columbus, Ohio, the typhoid fever death rate had 

 averaged over 'ji^ and had frequently been in excess of 100. 

 The filtration plant was completed in the fall of 1908. 

 The two years following showed rates of 20 and 18, and 

 during the next five years, the rates averaged 15.8. Similar 

 instances could be multiplied to almost any extent, for 

 in the whole field of sanitary science there is no clearer 

 proof of the adequacy of any measure taken for the pro- 

 tection of the public health than is to be found in the reduc- 

 tion of typhoid fever through water purification. 



As a general thing the water supphes of cities are of satis- 

 factory quahty. This is one advantage enjoyed by a large, 

 congested population over a smaller one. New York City, 

 for example, has been compelled by the gradually increasing 

 density of population in its environs to extend its water 

 supply catchment further and further afield, until today it 

 reaches into the Catskills and appropriates water at a 

 distance of 135 miles from the city. The sources of this 

 water are carefully protected and controlled; it is submitted 

 to the purifying action of storage in great reservoirs, and is 

 protected against any small remaining chance of pollution 

 by chlorination at several points in the system. The result 

 is a water supply that in point of view of safety and general 

 desirability is all that can be asked for and is excelled by 

 few if any large city supplies. 



The reason this amount of effort can be expanded to 

 procure a satisfactory water supply is the astonishingly low 

 per capita cost to the city dwellers. The cost of collecting, 

 storing, protecting, purifying and conveying from the moun- 

 tains and delivering to the people of the city their individual 

 daily allowance of a hundred and thirty gallons of a safe, 

 attractive, palatable water is about three-quarters of a 

 cent a day in New York City. 



The smaller town supplies are proportionately more 

 expensive, and cannot afford the same degree of protection. 



