300 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS water. The exocuticle, because of its high cross-link density, is unlikely to swell appreciably, but the relative absence of cross-links and the presence of ionic groups in the endocuticle will mean that it will absorb fairly large quantities of water (17). The resultant swelling may even be high enough to convert some of the endocuticular components into a gel. This could have interesting implications on the behaviour of the hair cuticle in the wet state and could perhaps contribute to the directional frictional properties of wet hair where there is a strong tendency towards felting. ACKNOWLEDGMENT We are grateful to Mr F. J. Bailey of Unilever Research Laboratory, Colworth House for undertaking amino acid analyses for us. (Received: loth April 1975) REFERENCES (1) Swift, J. A. and Bews, B. The chemistry of human hair cuticle--I: A new method for physical isolation of cuticle. J. Soc. Cosmet. Chem. 25 13 (1974). (2) Swift, J. A. and Bews, B. The chemistry of human hair cuticle--II: The isolation and amino acid analysis of the cell membranes and A-layer. J. Soc. Cosmet. Chem. 25 355 (1974). (3) Bradbury, J. H. and Ley, K. F. Separation and analysis of exocuticle and endocuticle. Aust. J. Biol. Sci. 25 1235 (1972). (4) Swift, J. A. The electron histochemistry of cystine-containing proteins in thin transverse sections of human hair. Jl R. Micros. Soc. 88 449 (1967). (5) Dobb, M. G., Murray, R. and Sikorski, J. Specific labelling of thiol groups in mammalian keratin suitable for electron microscope studies. J. Microsc. 96 285 (1972). (6) Kassenbeck, K.--private communication. (7) Stellwagen, R. H. and Cole, R. D. Chromosomal proteins. Ann. Rev. Blochem. 38 951 (1969) (8) Garrard, W. T., Pearson, W. R., Wake, S. K. and Bonner, J. Stoichiometry of chromatin proteins. Biochem. Biophys. Res. Commttn. 58 50 (1974). (9) Bradbury, J. H. The structure and chemistry of keratin fibres. Advn. Protein Chem. 27 111 (1973). (10) Swift, J. A. Unpublished observations on the application to human hair of an electron histochemical procedure devised by P. A. Kendall and E. A. Barnard, Jl R. Microsc. $oc. 81 203 (1963). Orwin, D. F. G. A polysaccharide-containing coat on keratinising cells of the Romney wool follicle. Aust. J. biol. $ci. 23 623 (1970). Swift, J. A. and Brown, A. C. The critical determination of fine changes in the surface architecture of human hair due to cosmetic treatment. J. $oc. Cosmet. Chem. 23 695 (1972). Makinson, K. R. The integration of various observations on the mechanisms of 'degra- dative' anti-felting treatments. J. Textile Inst. 64 228 (1973). Asquith, R. S., Otterburn, M. S. and Sinclair, W. J. Isopeptide crosslinks--their occurrence and importance in protein structure. Angew. Chem. 13 514 (1974). Rogers, G. E. Structural and biochemical features of the hair follicle. In: The epidermis, eds W. Montagna and W. C. Lobitz, 179 (1964) (Academic Press, New York). Harding, H. W. J. and Rogers, G. E. The occurrence of the e- (¾-glutamyl)lysine crosslink in the medulla of hair and quill. Biochem. Biophys. Acta 257 37 (1972). Leeder, J. D. and Watt, I. C. The stoichiometry of water sorption by proteins. J. CoIL Interface $ci. 48 339 (1974). (11) (12) (13) (14) (15) (16) (17)