Since 1915, when the United States Census Bureau designated the birth registration area, making available accurate figures on infant mortality, a stratification of the infant mortality rates of the cities of this country has been apparent annually. The high infant mortality rates of southern cities, the low rates of the Pacific coast cities and the rates of the cities of the middle Atlantic states, occupying an intermediate position, are phenomena well known to all observers of this important health index.
Infant mortality rates have declined annually since 1915, but the decline has not altered the manner of variation. In 1915, in a group of five cities, including Richmond, Buffalo, New Haven, St. Paul and Seattle, the infant mortality rates were arranged in that order, Richmond having the highest rate and Seattle, the lowest. In 1927, the infant mortality rates of all of these cities had declined markedly, but the order