THE VALUE OF PURE WATER 



59 



TABLE 2. 



EFFECT OF FILTRATION ON DEATH-RATES AT ALBANY, N. Y., AND A COMPARISON WITH TROY, N. Y., 

 WHERE THE WATER WAS NOT FILTERED. 



Remark: Filtered water was introduced into Albany in 1899. The water supply 

 of Troy has remained practically unchanged. 



Typhoid fever is by no means the only disease transmitted by 

 contaminated water. Dysentery and various other diarrheal diseases 

 precede it or follow in its train, and in most instances these are prob- 

 ably due to the same general sources of contamination as those which 

 caused the typhoid fever, although, of course, to different specific 

 infections. The reduction of the typhoid fever death-rate following 

 the substitution of a pure water for a contaminated water is often 

 accompanied by a drop in the death-rate from other diseases. Thus, 

 if the five years before and after filtered water was introduced into 

 Albany, N. Y., are compared, it will be seen that the reductions in 

 deaths from general diarrheal diseases and the deaths of children 

 under five years of age were much greater than in the case of typhoid 

 fever. There was also a reduction in malaria, but this probably 

 represents faulty diagnosis of typhoid fever cases before the introduc- 

 tion of the filters, rather than a real reduction of malaria. That the 

 reduction of infant mortality and deaths from diarrheal diseases was 

 not due to other conditions seems probable from the fact that in the 

 neighboring city of Troy, where the water supply was not changed, 

 there was no such diminution during the same period. (See Table 2.) 



Hazen, in his paper on " Purification of Water in America," read 



