92 ELEMENTS OF GENERAL SCIENCE 



102. Results of improved hygienic conditions. There are 

 many unquestioned instances of lowering the hu man death 

 rate through improvement of hygienic conditions (fig. 49). In 

 the city of Chicago prior to 1908 less than 2 per cent of the 

 milk was pasteurized, and the average death rate from typhoid 

 per 100,000 population was 24.8. In the years 1909, 1910, 



GERM DISEASES ALL OTHER DISEASES 



1870-79 ^ ^^^^^ ^^^^ ^ 1 14.60 ^^ ^ 0.58 



^^ ^ 13.82 i^ ^_^__ 7.G3 



1890-99 ^^^^^11.07 ^^ _ 



190009 ^^^^ 7.27 __^^_7.0S 



FIG. 49. A comparison of death rates 



The diagram shows th 1 ? number of deaths, per 1000 population, from germ 



diseases and from all other diseases, in one of the largest American cities. As 



knowledge and care have increased, the number of deaths from preventable 



diseases has decreased 



and 1911 between 50 per cent and 75 per cent of the milk 

 was pasteurized, and the average death rate per year from 

 typhoid per 100,000 population was 12.4. 



In the city of Boston a better milk and water supply was 

 introduced during the closing decade of the last century and 

 the first decade of this century. In 1910 it was claimed that 

 about one half of the milk used in Boston was pasteurized. 

 In the light of these facts the following table, showing the 

 Boston annual death rate from typhoid, is instructive : 



REDUCTION OF TYPHOID IN BOSTON* 



Typhoid deaths 

 Year per 100,000 population 



1891-1895 .............. 31.1 



1896-1900 .............. 30.6 



1901-1905 .............. 22.4 



1906-1910 .............. 16.0 



1911 ................ 9.0 



The average for 1909, 1910, and 1911 was 11.5 per 100,000 

 population. 



1 Jordan, General Bacteriology. W. B. Saunders Company, 1911. 



