RT Journal A1 AVERY M, MEAD J T1 SUrface properties in relation to atelectasis and hyaline membrane disease JF A.M.A. Journal of Diseases of Children JO A.M.A. Journal of Diseases of Children YR 1959 FD May 1 VO 97 IS 5_PART_I SP 517 OP 523 DO 10.1001/archpedi.1959.02070010519001 UL http://dx.doi.org/10.1001/archpedi.1959.02070010519001 AB Recent observations suggest that a low surface tension may be an important attribute of the lining of the air passages of the lung.1-4 The purpose of this paper is to present evidence that the material responsible for such a low surface tension is absent in the lungs of infants under 1,100-1,200 gm. and in those dying with hyaline membrane disease. The role of this deficiency in the pathogenesis of the disease is considered.Surface tension operates so as to minimize the area of the surface. In the lungs, where the internal surface (the alveolar lining) is curved concave to the airway, the tendency of the surface to become smaller promotes collapse. Although the forces not only of surface tension but also of the elastic tissue tend to collapse the lungs, their behavior differs in one important respect. When the lung contains only a small volume of air, the elastic