Note 17 — Chapter XIII

In the decade 1850-59 the death rate in New York City was 35.6 per cent., in the period 1900-13 only 15.3 per cent.; in Massachusetts, in the same periods, the death rate was 18.0 and 15.5 per cent. respectively. The diminution was due, partly to a change in the age-constitution of the population and partly to a progressive control of diseases.—Walter F. Willcox, "The Nature and Significance of the Changes in the Birth and Death Rates in Recent Years." American Statistical Association Quarterly, March, 1916, p. 2.