454 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS short, down hairs. The characteristic male facial, pubic, axillary and body hair develops i•x response to androgenic hormones. But women also develop axillary and the lower triangle of pubic hair, and this depends not on the presence of the ovaries but of the adrenals (27). Abnormally, but not perhaps infrequently, women tend to develop hirsutism of the male type. Sometimes this is associated with abnormally high excretion hence pro- duction-of low potency adrenal androgens (17-oxosteroids) sometimes it is not, but it seems that some of these cases of so called "idiopathic" hirsutism may be due to the production of the potent male hormone testosterone (28). There is no reason to suppose from these facts that different regions of the body respond to specific steroid hormones it is only necessary to postulate that they have different sensitivities to androgens. Follicles of the axillary and lower pubic regions are most sensitive, and will respond to the low potency androgens produced by the adrenal of the normal female. The upper pubic, body and facial hair need either the high potency testo- sterone, produced normally in the male and perhaps abnormally in the female, or high amounts of adrenal 17-oxosteroids. It is something of a paradox that the scalp follicles which require no hormonal stimulation to produce long hair, in some individuals change under the influence of androgens to produce only fine and cosmetically useless fluff. Follicles do not seem to be lost in the process of balding, they regress. Both the dermal papilla and the matrix become proportionally smaller (29) and the surrounding dermis appears to age with abnormal rapidity (30). It is now undisputed that the disposition to patterned bald- ness is hereditary but that, as first suggested by Hamilton (31), its mani- festation requires the presence of male hormone, as well as the ravages of time. Eunuchs do not go bald unless they are treated with testosterone but the follicular regression of baldness cannot, apparently, be reversed by castration even if one were prepared to make the sacrifice (32). Patchy baldness, or alopecia areata, like patterned baldness, does not involve complete cessation of follicular activity, but the hair bulbs remain in a phase of growth corresponding to that of early anagen and no clinically detectable hairs may be present (33). The whole follicle is very much smaller than normal. The papilla is reduced in size, but the matrix is proportionally smaller still and thus the proportions of the follicle are changed (29). A granular infiltrate has been observed in the dermis. The condition is reversible under treatment with adrenocortical steroids such as cortisone or prednisone. It may cure itself spontaneously, and it is claimed, on what seems rather inconclusive evidence, that cure can be aided by miscellaneous local treatments. (Received: $1st January 196•t.)

THE ACTIVITY OF THE HAIR FOLLICLE 455 REFERENCES (1) A.M. Kligman J. Invest. Dermatol. 33 307 (1959). (2) R. J. Myers and J. B. Hamilton Ann. N.Y. Acad. Sci. 53 562 (1951). (3) A.M. Kligman A.M. A. Arch. Dermatol. 83 175 (1961). (4) J. H. Kim, F. Herrmann and M. B. Sulzberger J. Invest. Dermatol. 38 351 (1962). (5) E. Johnson J. Endocrinol. 16 337 (1958). (6) F. J. Ebling and E. Johnson Symposia of the Zoological Society of London 12 79 (1964). (7) T. H. Bissonnette Anat. Record 63 159 (1935). (8) N. E. Harvey and W. V. Macfarlane Australian J. Biol. Sci. 11 187 (1958). (9) A. Watson Proc. Zoological Society of London 141 823 (1963). (10) F. J. Ebling and E. Johnson ]. Embryol. Exptl. Morphol. 7 417 (1959). (11) F. J. Ebling and E. Johnson ]. Embryol. Exptl. Morphol. 9 285 (1961). (12) E. Johnson and F. J. Ebling In press. (13) E. H. Mercer Keratin and Keratinisation (1961) (Pergamon Press, Oxford). (14) F. J. Ebling and G. R. Hervey ]. Embryol. Ezptl. Morphol. 12 In press (1964). (15) E. Johnson ]. Endocrinol. 16 351 (1958). (16) M.P. Mohn in W. Montagna "The Biology of Hair Growth" Chapter 15 (1958) (Academic Press Inc., New York). (17) B. L. Baker and W. L. Whitaker Anat. Record 102 333 (1948). (18) H. J. Whiteley, ]. Endocrinol. 17 167 (1958). (19) E. Johnson J. Endocrinol. 16 360 (1958). (20) F. J. Ebling and E. Johnson ]. Endocrinol. 29 193 (1964). (21) Y. L. Lynfield ]. Invest. Dermatol. 35 323 (1960). (22) J. B. Brown Recent Progress in the Endocrinology of Reproduction 335 (1959) (Academic Press, New York). (23) T. H. Bissonnette and E. Wilson Science 89 418 (1939). (24) T. H. Bissonnette and E. E. Bailey Ann. N.Y. Acad. Sci. 45 221 (1944). (25) N. T. M. Yeares Australian J. Agric. Research 6 891 (1955). (26) E.G. Rennels and W. P. Callahan Anat. Record 135 21 (1959). (27) P. Flesch in S. Rothman "Physiology and Biochemistry of Skin", Chapter 26 (1953) (University Press, Chicago). (28) B. W. L. Brooksbank Physiol. Revs. 41 623 (1961). (29) E. J. Van Scott and T. M. Ekel J. Invest. Dermatol. 31 281 (1958). (30) M. Singh and J. McKenzie J. Anat. 95 569 (1961). (31) J. B. Hamilton Am. J. Anat. 71 451 (1942). (32) J. B. Hamilton J. Clin. Endrocinol. and Metabolism 20 1309 (1960). (33) E. J. Van Scott J. Invest. Dermatol. 31 35 (1958). (34) E. H. Mercer and M. S.C. Birbeck J. Biophys. Biochem. Cytol. 3 203, 215, 223 (1957). DISCUSSION DR. J. BLAKE: Could you distinguish between roles played by hormones vs. intercellular contact (34) in cell differentiation in the growth of hair? TuE L•CTUR•R: I do not know about distinguishing between the roles played by hormones and intercellular contact. I make a clear distinction between the effect of hormones on the initiation of follicular activity and on the growing hair. The initiation of follicular activity is affected by a number of hormonal states, whereas the rate of hair growth was, in our experiments, only clearly affected by oestrogens, which reduce the rate of hair growth. I do not know how they act they may inhibit cell division, but by analogy