Physiology and pathology approach each other so closely in obstetrics that it is often difficult to distinguish the one from the other. In fact, there are two groups of obstetricians, the one typified by Eden,1 who considers pregnancy and parturition essentially physiologic; the other, by DeLee,2 who considers all labor abnormal. Between these extremes, there is a large group that considers the pregnant woman to be just on the dividing line between the normal and the abnormal, usually on the normal side, but often, with the least provocation, getting over the line into the abnormal.
This condition of affairs is equally true of the new born, as one readily realizes in studying the causes of death of infants at birth and shortly thereafter. In Williams' classic study of infant deaths,3 the next to the largest class of etiologic factors was the unknown (18 per cent.). If to