The results of a statistical analysis of the relation of various lesions in the lungs of newborn infants to each other, and to the age and sex of the babies, are presented. The pulmonary lesions studied were: atelectasis, emphysema, interstitial emphysema, hemorrhage, acute pneumonia, edema, presence of squamous cells in alveoli, hyaline membranes, and immaturity. Of 45 possible relations analyzed (e.g., atelectasis and hyaline membranes, immaturity and acute pneumonia, etc.), 14 gave results significantly different from those due to chance. Of particular note, in view of current opinion on the genesis of neonatal pulmonary hyaline membranes, was the failure to demonstrate a significant relation of pulmonary edema to any of the other pulmonary lesions studied.