Survey of Deaths of Infants Under 30 Days of Age. — In order to determine ways of further decreasing infant mortality in Chicago during 1935, the Board of Health made an intensive field investigation of the deaths of every infant aged 30 days or less. A questionnaire was devised covering sixty-eight items relating to the prenatal period, the process of delivery, and postnatal care. This questionnaire served as a framework on which the whole structure of the inquiry was built and developed. Table 1 presents the details concerning the birth rates, stillbirth rates, and infant mortality rates in Chicago for the period from 1925 to 1935 inclusive, showing especially the rates for deaths under 1 month and from 1 month to 12 months. The accuracy of calculation of infant mortality rates on the basis ofthe number of reported deaths under 1 year per thousand live births is dependent, among