Special studies have shown that at least 5 per cent of all infants born alive are born prematurely.1 This means that more than 114,000 infants were born prematurely in 1938. In the same year more than 31,000 neonatal deaths were reported by the United States Bureau of the Census as directly due to premature birth. The neonatal mortality rate from this cause in 1938 was 13.8 per thousand live births. These figures indicate the importance of the problem at the present time.
The earliest recognition in this country of the role that premature birth plays in infant mortality appears to have been an address on infant mortality given before the American Medical Association in 1857 by Reese.2 He stated: "... we include among the infant mortality all those recorded interments marked as stillborn and premature births, the extent of which, and especially their amazing increase, constitutes one of the