Page:Popular Science Monthly Volume 84.djvu/417

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THE PROGRESS OF SCIENCE
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put a merely commercial valuation on the lives saved, it amounts to a billion dollars a year. It would surely be reasonable to spend the amount thus saved by better living conditions, improved hygiene and more efficient medical service to promote further advances in the same direction.

The death rate has declined in all the great nations, with the possible exception of Russia and Japan. Thus since 1886 the decrease in England has been about 6, in Germany about 9, in France about 3. These great differences for different nations are in large measure due to the age constitution of their populations. Thus England has doubled its population by natural increase in sixty years and Prussia in fifty years, but now the birth rate is rapidly declining. There is thus in their populations a small proportion of old people and a decreasing proportion of young children, which in large measure explains why the death rate is lower than in France where the population has been nearly stationary and there are nearly twice as many old people. The death rate for New York City in 1912 was 14.5, and for the entire state 15, but this does not mean that conditions are more favorable to health and to long