484 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ACKNOWLEDGMENT The authors thank Lever Brothers Company for permission to publish this paper. REFERENCES (1) E. R. Cooper and B. F. Van Duzee, Diffusion theory analysis oftransepidermal water loss through occlu- sive films, J. Soc. Cosmet. Chem., 27, 555 (1976). (2) A. F. E1-Shimi and H. M. Princen, Diffusion characteristics of water vapor in some keratins, Colloid Polym. Sci. (in press). (3) K. Grice, H. Sattar, and H. Baker, The effect of ambient humidity on transepidermal water loss, J. In- vest. Dermatol., 58, 343 (1972). (4) A. B. Goodman and A. V. Wolf, Insensible water loss from human skin as a function of ambient vapour concentration, J. Appl. Physiol., 26, 203 (1969). (5) M. M. Rieger and D. E. Deem, Skin moisturizers. I. Methods for measuring water regain, mechanical properties, and transepidermal moisture loss of stratum corneum, J. Soc. Cosmet. Chem., 25, 239 (1974). (6) L.J. Vinson, E. J. Singer, W. R. Koehler, M.D. Lehman, and T. Masurat, The nature of the epidermal barrier and some factors influencing skin permeability, Toxicol. Appl. Pharmacol., 7, 7 (1965).