INFLUENCE OF TEMPERATURE AND RH ON STRATUM C:ORNEUM 243 layers remain intact. The cracking of the surface layer is seen as flaking of the skin surface and commonly occurs in areas subjected to flexing such as the finger webs. In more severe cases of chapping, complete rupture of the corneum occurs when extensibility of the entire comeurn is reduced to the extent where it cracks under tension. Any external factors, such as cold or drying winds, which increase the gradient of temperature or water content will lead to a greater degree of skin flaking or chapping. Factors which reduce the gradients, such as clothing, will reduce flaking and chapping. (Received: 12th January 1972) REFERENCES (1) Blank, I. H. Factors which influence the water content of the stratum corneum. J. Invest. Dermatol. 18 433 (1952). (2) Singer, E. J. and Vinson, L. J. The water binding properties of skin. Proe. Sei. Sect. Toilet Goods Ass. 46 29 (1966). (3) Middleton, J. D. The mechanism of water binding in stratum corncure. Brit. d. DermatoL 80 437 (968). (4) Wildnauer, R. H., Bothwell, J. W. and Douglass, A. B. Stratum corneum biomechanical properties. I. Influence of relative humidity on normal and extracted human stratum corneum. J. Invest. DermatoL 56 72 (1971). (5) Gaul, L. E. and Underwood, G. B. Relation of dew point and barometric pressure to chap- ping of normal skin. J. Invest. Dermatol. 19 9 (1952). (6) Middleton, J. D. The effect of temperature on extensiblity of isolated corneum and its relation to skin chapping. Brit. J. Dermatol. 81 717 (1969). (7) Middleton, J. D. The mechanism of action of surfactants on the water binding properties of isolated stratum corneum. J. $oe. Cosmet. Chem. 20 399 (1969). (8) Acheson, D. T. in Humidity and moisture measurement 3 521 (1965) (Reinhold, New York).

J. Soc. Cosmet. Chem. 24 245-258 (1973) (•) 1973 Society of Cosmetic Chemists of (7reat Britaln A critical evaluation of the methods available for measurement of antiperspirancy T. A. BAKIEWICZ* Presented on the 12th April 1972 in Oxford, at the Symposium on 'Skin--Environmental responses and protection', organized by the Society of Cosmetic Chemists of Great Britain. Synopsis---The different METHODS for the evaluation of ANTIPERSPIRANTS are reviewed. The difficulties in INTERPRETATION of the results obtained using these different METHODS are discussed. INTRODUCTION The expansion in sales of antiperspirants (1, 2) in recent years has resulted in the appearance on the market of many new products. The evaluation involved in the development of these products, as well as the research towards new actives, has resulted in a renewed interest in the methods for the evaluation of antiperspirants. The purpose of this com- munication is to discuss, critically, the methods available to the cosmetic scientist for the evaluation associated with the development of new products, and methods for providing technical support for marketed form.ulae. ECCRINE SWEATING The sweat glands can be divided into two types, eccrine and apocrine. The apocrine glands, in man, have a limited distribution on the body *Unilever Research, Laboratory, 455 London Road, Isleworth, Middlesex. 245