Spitz examined one hundred forty-five newborn infants and describes a reflex which until now has not been specifically mentioned in the literature. If one gently strokes the dorsal surface of the end phalanx of the four fingers, dorsal extension can be elicited. This reaction is most consistent during the first days of life and already begins to recede noticeably between the

second and third week. Within the first week this reflex is much more reliably obtained than the sucking, cremasteric or Moro reflex.