Chemical Indentification of the Surface-active Material Isolated from Calf Lung

The surface-active material, obtained from the foam of calf lungs, contained a high concentration of phospholipids, of which dipalmitoyl-alpha-lecithin being predominant. The phosphatidylethanolamine of the surface-active material con-tained highly unsaturated fatty acids. Both the composition and fatty acid patterns of the total phospholipid as well as lecithin which were isolated from the surface-active lung foam were found to be similar to those from the lung tissue. This finding indicates that the surface-active material has its origin in the lung parenchyma, most likely in the alveolar epithelium.