442 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (1957) Birbeck, M. S.C. and Mercer, E. H. The electron microscopy of the human hair follicle. I. Introduction and the hair cortex. J. Biophys. Blochem. Cytol. 3 203 (1957). (36) Fraser, R. D. B. and Rogers, G. E. Microscopic observations of the alkaline-thioglycolate extraction of wool. Blochim. Biophys. Acta 12 484 (1953) Fraser, R. D. B. and Rogers, G. E. Origin of segmentation of wool cortex. Blochim. Biophys. Acta. 13 297 (1954) Dusenbury, J. H. and Coe, A. B. Differential dyeing as an indication of bilateral structure in wool: new findings. Text. Res. J. 25 354 (1955) Dusenbury, J. H. and Menkart, J. The present state of the ortho and paraconcept. Proc. Int. Wool Text. Res. Conf., Australia F 142 (1955) Ahmad, N. and Lang, W. R. Ortho-para cortical differentiation in 'anomalous' Merino wool. Aust. J. Biol. Sci. 10 118 (1957) Thorsen, W. J. Estimation of cortical com- ponents in various wools. Text. Res. J. 28 185 (1958) Kassenbeck, P., Jacquemart, J. and Monrocq, R. Mbthodes de caractbrisation des fibres kbratiniques en microscopic optique. 3rdlnt. Wool Text. Res. Conf., Paris 1 209 (1956) Brown, T. D. and Onions, W. J. Anoma- iies in the microscopic structure of some wools. Nature (London) 186 93 (1960) Bon•s, R. M. and Sikorski, J. The histological structure of wool fibres and their plasticity. J. Text. Inst. 58 521 (1967). (37) Leveau, M., Cebe, N. and Parisot, A. Heterogeneity of the wool fibre and the Allwbrden reaction. Bull. Inst. Text. Fr. 42 7 (1953) Dusenbury, J. H., Mercer, E. H. and Wakelin, J. H. The influence of chemical treatment on the properties of wool. I. Alkali solubility as a measure of sulfuric acid degradation. Text. Res. J. 24 890 (1954) Dusenbury, J. H. Characterization of the cortical structures of keratin fibres by urea-bisulphite solubility. J. Text. Inst. 51 T756 (1960) Leach, S. J., Rogers, G. E. and Filshie, B. K. Selective extraction of wool keratin with dilute acid. I. Chemical and morphological changes. Arch. Blochem. Biophys. 105 270 (1964) Mercer, E. H. A note on the digestion of wool by clothes-moth larvae. Blochim. Biophys. Acta 15 293 (1954) Dobb, M. G. Electron-diffrac- tion studies of keratin cells. J. Text. Inst. 61 232 (1970) Mirb, P. and Erra, P. Action of sodium hydroxide on the morphological structure of wool. Bull. Inst. Text. Fr. 23 841 (1969). (38) Kassenbeck, P. Considbrations sur la localisation des liaisons cystiniques inter- et intra- chaines et sur les teneurs en soufre compar&s des fractions corticales 'ortho' et 'para'. 3rd Int. Wool Text. Res. Conf., Paris 1 367 (1965). (39) Kulkarni, V. G., Robson, R. M. and Robin, A. Studies on the orthocortex and paracortex of Merino wool. J. AppL Polym. Sci., Appl. Polym. Symp. 18 127 (1971). (40) Filshie, B. K. and Rogers, G. E. The fine structure of •-keratin. or. Mol. Biol. 3 784 (1961) Fraser, R. D. B., MacRae, T. P. and Rogers, G. E. Molecular organization in alpha- keratin. Nature (London) 193 1052 (1962). (41) Fraser, R. D. B., MacRae, T. P. and Millward, G. R. The structure of •-kerafin micro- fibrils. J. Text. Inst. 60 343 (1969). (42) Dobb, M. G. Protofibrils in ct-keratin. o r. Mol. Biol. 10 156 (1964) Rogers, G. E. and Clarke, R. M. Keratin protofilaments and ribosomes from hair follicles. Nature (London) 205 77 (1965) Dobb, M. G. and Rogers, G. E. Electron microscopy of fibrous keratins. Symposium on Fibrous Proteins, Australia 267 (1968) (Butterworths, Sydney). (43) Millward, G. R. Cellulose contamination: a possible source of error in the interpretation of previous experimental evidence for the a-keratin protofibril. J. Cell. Biol. 42 317 (1969) Fraser, R. D. B., MacRae, T. P. and Millward, G. R. Fact and artefact. J. Text. Inst. 60 498 (1969). (44) Johnson, D. J. and Sikorski, J. Molecular and fine structure of alpha-keratin (I). Nature (London) 194 31 (1962) Dobb, M. G., Johnson, D. J. and Sikorski, J. Molecular and fine structure of alpha-keratin (II). 5th Int. Conf. Electron Micro c., Philadelphia 2 T4 (1962) Johnson, D. J. and Sikorski, J. Molecular and fine structure of alpha-keratin (III). Proc. 3rd Eur. Reg. Conf. Electron Microsc., Prague B63 (1964) Johnson, D. T. and Sikorski, J. Molecular and fine structure of a-keratin (IV). Nature (London) 205 266 (1965) Johnson, D. J. and Sikorski, J. Fine and ultrafine structure of keratin (V). 3rd Int. Wool Text. Res. Conf., Paris 1 147 (1965) Dobb, M.G. and Sikorski, J. Fine and ultrafine structure of mammalian keratin. J. Text. Inst. 60 497 (1969). (45) Ryder, M. L. in Hearle, J. W. S. and Peters, R. H. Fibre Structure 547 (1963) (Butterworths, London). (46) Bradbury, J. H. and O'Shea, J. M. Keratin fibres. II. Separation and analysis of medullary cells. Aust. J. Biol. Sci. 22 1205 (1969). (47) Steinert, P.M., Harding, H. W. J. and Rogers, G. E. The characterization of protein-bond citrulline. Biochim. Biophys. Acta 175 1 (1969).

STRUCTURAL ASPECTS OF KERATIN FIBRES 443 (48) Harding, H. W. J. and Rogers, R. E. g-(¾-Glutamyl)lysine cross-linkage in citrulline- containing protein fractions from hair. Biochemistry 10 624 (1971) Harding, H. W. J. and Rogers, R. E. The occurrence of the ½-(•-glutamyl)lysine cross-link in the medulla of hair and quill. Biochim. Biophys. Acta 257 37 (1972). (49) Swift, J. A. Personal communication. (50) Baddid, C. B. Structure and reactions of human hair keratin: an analysis by infrared spectroscopy. J. Mol. Biol. 38 181 (1968). (51) Swift, J. A., Ph.D. Thesis, University of Leeds (1963). (52) Breuer, M. M. Personal communication. (53) Mason, H. S., Ingram, D. J. E. and Allen, B. Free radical property of melanins. Arch. Blochem. Biophys. 86 225 (1960). (54) Sacchi, S., Lanzi, G. and Zanotti, L. Electron spin resonance research on human hairs under varying physiological and experimental conditions, in Montagna, W. and Dobson, R.L. Advances in Biology of Skin, Vol. 9, Hair Growth (1969). (Pergamon, Oxford). (55) Swift, J. A. The electron histochemistry of cystinc-containing proteins in thin transverse section of human hair. J. Roy. Microsc. $oc. 88 449 (1968). (56) Holmes, A. W. Degradation of human hair by papain. II. Experiments in the isolation and identification of the protective substance. Text. Res. J. 34 777 (1964). (57) Leon, N.H. Unpublished data. (58) Holmes, A. W. Degradation of human hair by papain. I. The pattern of degradation. Text. Res. J. 34 706 (1964). (59) Swift, J. A. and Holmes, A. W. Degradation of human hair by papain. III. Some electron microscope observations. Text. Res. J. 35 1014 (1965). (60) Bradbury, J. H., Leeder, J. D. and Watt. I. C. The cell membranes of wool. J. Appl. Polym. $ci., Appl. Polym. $ymp. 18 227 (1971). 61) Sanger, F. The free amino groups of insulin. Blochem. J. 39 507 (1954). 62) Middlebrook, W. R. The chain weight of wool keratin. Blochim. Biophys. Acta. 4 547 (1951). (63) Thompson, E. O. P. Terminal amino groups in wool and S-carboxymethyl kerateine 2. Aust. J. Biol. $ci. 10 225 (1957). (64) Tibbs, J. Ph.D. Thesis, University of Leeds (1951) Speakman, J. B. Neue Forschungsar- beiten fiber die Chemic der Wolle. Melliand Textilber. 33 823 (1952). (65) Kerr, M. F. and Godin, C. N- and C-terminal end groups of hair keratin. Can. J. Chem. 37 11 (1959). (66) H'mreel, R. Comparative chemical studies of physiological and pathological keratins. I. Quantitative determination of N-terminal amino acids in calluses, psoriasis scales, nails and hair. Arch. Klin. Exp. Dermatol. 209 97 (1959). (67) Woodin, A.M. Structure and composition of soluble feather keratin. Blochem. J. 63 576 (1956). (68) Thompson, E. O. P. A method for the isolation of DNP-cysteic acid and its application to the determination of N-terminal half-cystine residues in wool. Aust. J. Biol. $ci. 12 303 (1959). (69) O'Donnell, I. J. and Thompson, E. O. P. Oxidized wool. VI. Interactions between high- and low-sulphur proteins and their significance in the purification of extracted wool proteins. Aust. J. Biol. $ci. 15 740 (1962). (70) Siepmann, E. and Zahn, H. Automatic analysis of water-soluble 2,4-dinitrophenyl amino acids by chromatography on nylon powder. 3rd Int. Wool Text. Res. Conf., Paris 1 303 (1965). (71) Asquith, R. S., Chan, D. and Otterburn, M. S. An electrophoretic method for the deter- mination of 'bound' e-aminolysine in proteins. J. Chromatogr. 43 382 (1969). (72) Fromageot, C., Jutisz, M., Meyer, D. M. and P6nasse, L. The characterization of terminal carboxyl groups of proteins. Application to insulin. Blochim. Biophys. Acta 6 283 (1950). (73) Speakman, J. B. Proc. Int. Wool Text. Res. Con(, Australia C 474 (1955). (74) Blackburn, S. and Lee, G. R. Terminal carboxyl groups of wool keratin. J. Text. Inst. 45 T487 (1954). (75) Akabori, S., Ohno, K. and Narita, K. HydrazJnolysis of proteins and peptides: method for the characterization of carboxyl-terminal amino acids in proteins. Bull. Chem. Soc. Japan 25 214 (1952) Braun, V. and Schroeder, W. A. A reinvestigation of the hydrazinolytic procedure for the determination of C-terminal amino acids. Arch. Blochem. Biophys. 118 241 (1967). (76) Bradbury, J. H. The hydrazinolysis of insulin, lysozyme, wool proteins and wool. Blochem. J. 68 482 (1958). (77) Alexander, P. and Earland, C.F. Structure of wool fibres. Isolation of an a- and 13-protein in wool. Nature (London) 166 396 (1950).