Page:Popular Science Monthly Volume 86.djvu/317



HE trend of American vitality could best be determined by comparing a series of life tables for the last three or four decades. These would tell us whether the expectation of life at each age had increased or decreased during this period; but, unfortunately, no such tables are at hand. We are only now beginning to realize the value of such statistical devices for measuring our vital resources. The Federal Bureau of the Census is for the first time engaged in preparing comprehensive life tables. These will, we hope, give us fundamental data on American life expectancy in the registration area. For the country as a whole, nothing worthy of consideration will be available until our vital statistics have been much improved and the registration area extended to include all the states.

Our analysis will, therefore, be at best inadequate and incomplete. We have, in the first place, a few life tables for some cities and states which tend to show the trend of vitality in these places. The New York City tables for the period 1909 to 1911, for example, indicate that the probable span of life for children under five has been extended by about ten years since the earlier tables for the period 1879 to 1881 were prepared. The improvement in life expectancy continues until about age 35. From this age onward the expectation becomes reduced. In Massachusetts, the reduction in the expectation of life has occurred at an even earlier age. Life tables for a few other states show similar