154 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS REFERENCES (1) C. R. Robbins, Chemical and Physical Behavior afHuman Hair (Springer Verlag, New York, 1988). (2) C. Zviak, The Science of Hair Care (Marcel Dekker Inc., New York, 1986). (3) The DE instrument was constructed by Norman Den Beste, of Den Beste Associates, Arlington Heights, IL. (4) L. J. Wolfram and D. L. Underwood, The equilibrium between the disulfide linkage in hair keratin and sulfite or mercaptan, Textile Res. J., 36, 947 (1966). (5) R. R. Wickett, Kinetics of hair reduction using a single fiber technique, J. Sac. Cosmet. Chem., 34, 301 (1983). 6. A. Shansky, The osmotic behavior of hair during the permanent waving process as explained by swelling measurements, J. Sac. Cosmet. Chem., 14, 427 (1963).