Long before serum bilirubin levels were measured, astute clinicians observed differences in neonates with progressive icterus. Such descriptive terms as benign, infective, toxic, and obstructive jaundice were introduced in an effort to better understand the problem. It was not until the mid 1930s, when Evelyn and Malloy popularized their method of microbilirubin determination, that serial bilirubin measurements became feasible. Since the classical paper by Davidson et al in 1941,1 many investigators have made contributions toward a better understanding of hyperbilirubinemia and its effects on the neonate. However, many basic questions remain unanswered.
In a current issue of the American Journal of Diseases of Children a clinical method for evaluating the progression of jaundice in newborns is described.2 In infants with progressive hyperbilirubinemia, the jaundice begins on the face and proceeds to the trunk, the extremities, and finally to the palms and soles. It is suggested that inspection of