THE LENGTHENING SPAN OF LIFE 



Each child born in a civilized community today starts out with a much better chance 

 of getting past his tenth, twentieth or fortieth year than had his parents or grand- 

 parents and their contemporaries. He is not so likely to succumb to diphtheria, small- 

 pox, typhoid, malaria, scarlet fever, or other communicable disease. He has an even 

 chance of attaining seventy years 



officials inform physicians and private citizens about improved or standard 

 tests, serums, and other special materials and procedures for curing or pre- 

 venting disease. Later it is found to be more effective and more economical 

 to supply materials, tests, immunizations, inspections, and other services 

 directly through a central agency. 



Water Supply and Sewage Disposal As population becomes more 

 dense, surface wells become less adequate, and they are in increasing danger of 

 pollution. Deep wells are, as a rule, quite satisfactory for small towns, but 

 cannot supply large cities. Cities usually depend upon lakes, streams and 

 reservoirs that collect the runoff from a vast watershed. The entire water- 

 shed, as well as the reservoir, must be protected against pollution by excreta 

 and industrial wastes. Suspended matter and harmful germs are removed by 

 means of storage, chemical treatment, settling basins, filtration, or some com- 

 bination of these methods, depending upon the circumstances. Bacteria in 

 the water are destroyed by very small amounts of chlorine. 



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