COSMETIC FILMS ON THE SKIN 159 in the foregoing experiments, human sebum forms a porous film on the skin surface. This porous film of sebum allows the skin to exchange moisture, carbon dioxide, and oxygen with the environment. Conse- quently the use of occlusive films as cosmetic products on the surface of the skin to prevent moisture loss appears to be a nonphysiological treatment because it potentially interferes with natural functions of the skin. In spite of its porosity, the sebum film serves as a protective cover for the skin. It protects the skin, among other things, against removal from the skin of NMF by excessive contact with water during swimming or bathing. The experimental results presented here strongly suggest that'syn- thetic NMF (based on the analysis of natural NMF) may be considered an effective moisture control. Since effective moisture regulation of the epidermis through use of a synthetic NMF seems feasible, the question of applying occlusive films to the skin surface appears less desirable. SUMMARY It has been shown that the natural moisturizing factor of the human skin can be duplicated synthetically. Experiments have shown that this synthetic NMF is as effective as the natural moisturizing factor of the human skin. The use of synthetic NMF makes unnecessary use of occlusive films on the skin surface to prevent moisture loss. It has been shown that the human sebum forms porous films on the skin surface and that this property depends on the content of branched- chain compounds in human sebum. The addition of aliphatic branched- chain compounds to cosmetic bases makes possible formulation of prod- ucts forming porous films similar to those of human sebum on the skin. (Received August 8, 1966) REFERENCES (1) Jacobi, 0., Kolloid Z., 114, 2 (1949). (2) Schneider, W., and Schuleit, H., Arch. Dermatol. Syphilol., 195,434 (1951). (3) Blank, J. H., J. Invest. Dermatol., 18, 6 (1952). (4) Spiel H. W., and Pascher, G., Hautarzt, 7, 2 (1956) Acta Dermato-Venereol. Proc., 2, 14 (1957). (5) Szakall, A., and Stripel, H., Die W•rkung yon Waschmitteln auf die Haut, Hfithig He_ide[- berg, 1957. (6) Flesch, P., J. Invest. Dermatol., 1,63 (1958). (7) Flesch, P., and Esoda, E. C. Jackson, J. Invest. Dermatol., 28, 5 (1957), (8) Gartmann, H., Deut. Med. Wochenschrift, 83, 9 (1958).

160 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) Peck, S. M., and Glick, A. W., Y. Soc. Cosmetic Chem., 7,530 (1956). Shelmire, J. R., J. Invest. Dermatol., 26,105 (1956). Laden, K., J. Soc. Cosmetic Chem., 13,455 (1962). Fox, C., et al., J. Soc. Cosmetic Chem., 13,263 (1962). Blank, J. H., Proc. Scl. Sect. Toilet Goods Assoc., 23, 19 (1955). Blank, J. H., J. Am. Med. Assoc., 164,412 (May, 1957). Flesch, P., Am. Perfumer &' Cosmetics, 77, 77 (October, 1962). Weitzel, G., Hoppe-Seylers Z. Physiol. Chem., 285, 220, 230 (1950) 287, 66, 254 (1951) 288, 174, 189,200, 251,266 (1951) :]01, 17, 26 (1955) Fette Seifen Anstrichmittel, 63,171 (1961). Jacobi, 0., Perfumery Essent. Oil Record, :]4, 35 (1963). Gregory, H., Shirley Inst. Mere., 20,163 (1946). Reinertson, R. P., and Wheatley, V. R., J. Invest. Dermatol., :]2, 49 (1959). Nicolaides, N., and Kellum, R. E., J. Am. Oil Chemists' Soc., 42, 8 (1965).