HEALTH AND DISEASE 



429 



we consider the specific case of the disease known as smallpox. In 

 the eighteenth century 5,000,000 people are said to have died from 

 it; one hundred years ago it was exceedingly common in all large 

 cities in this country. To-day an epidemic of smallpox is impos- 

 sible, thanks to the discovery of vaccination and prompt action by 

 the health department. Tuberculosis at the present time kills more 

 people annually than any other disease, and yet it is believed by 

 sanitary hving we will stamp out the disease within fifty years if 



Deaths from tuberculosis contrasted with the other contagious diseases in 

 the center of New York in 1908. 



we go on at the present rate. Public hygiene is largely responsible 

 for the lessening of deaths from typhoid fever and other diseases 

 which are transmitted through the milk or water supply. It is 

 estimated that piu-e milk, pure water, and pure air supplied to all 

 would lengthen the average human hfe in the United States eight 

 years. At the present rate human life is being lengthened about 

 14 years every century in Massachusetts, 17 in Europe, and 27 

 per century in Prussia.' In India, on the other hand, where little 

 hygiene is kno\vn or practiced among the masses of people, the 

 length of life is stationary. 



' This result ia obtained by the saving of the lives of thousands of young children , 

 who now grow to become adults. 



