62 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS in the shoe materials should not be overlooked. There may well be a sequence of events, i.e. primary deterioration of a particular shoe material by sweat which renders it susceptible to further deterioration by saprophytic fungi. At either stage sensitizers might be created. Sensitivity to rubber is now rather less of a problem than 5 or 10 years ago since the widespread use of injection-moulded PVC soles on a wide range of men's and children's shoes. Rubbers are still used for special purpose footwear and in industrial and military boots but it has virtually disappeared from the ordinary every-day shoe. In connection with the possible dermatitic effect of vinyls, it is significant that there has been no obvious reaction to the extensive use of vinyl-coated fabrics in women's shoes. Footwear applications for polyurethane-coated fabrics are now growing rapidly and it will be important to watch for sensitivity especially because of the wide range of polymer structures which arise in polyurethane technology. In particular, possible unreacted isocyanates (toluylene di- isocyanate (TDI) and diphenylmethane di-isocyanate (MDI)) could present a real dermatitic hazard: however, the reactivity of these isocyanates with water suggests that any unreacted material would soon disappear, probably before the shoes reach the shops. Where dermatitic sensitivity occurs it is now usually possible to find an alternative material. Good examples are the availability of the permeable poromeric materials, e.g. Corfam, Porvair, which can be worn when leather uppers cause dermatitis, also the replacement of rubber toe-puffs some years ago by the nitrocellulose impregnated fabric composites, e.g. 'Celastik'. This paper has been somewhat of a mixture but the work on the modified PA test is being described for the first time, although a more detailed description of this work will be published elsewhere. A rather wide range of topics have been covered but the connecting thread has been the possible problem accompanying high levels of sweat accumulation which will occur if impermeable shoes for men and children are introduced on a large scale in Great Britain. With respect to the condition of the skin of the foot in healthy and diseased feet it is a development deserving of our awareness. (Received: 29th February 1972) REFERENCES (1) Hole, L. G., Holt, T. A. and Grimwade, D. $ATRA Bulletin 12 3 (1966). (2) Keech, B. and Hole, L. G. SATRA Poromerics Progress 3 No. 1 (1971). (3) Brooks, F. and Mitton, R. J. Soe. Leather Trades Chern. 52 42 (1968). (4) Grimwade, D. and Burry, H. S. SATRA Research Report RR.162. (5) Gran, J. J. Soc. Leather Trades Chern. 43 2 (1959).

HEALTH AND HYGIENE OF FOOT SKIN 63 (6) Kennedy, K. and Ogilvie, D. R. M. L. TM. 559. Defence Research Board. Department of National Defence, Canada (1964). (7) Miiller-Limmroth, W. and Diebschlag, W. W. Das Leder 22 (1971), SATRA Shoe Materials Progress 3 361 (1971). (8) Keech, B. and Hole, L. G. J. Soc. Leather Trades Chem. 55 3 (1970). (9) Buser, K. R., Chu, I. C. and Graham, P. J. Poromerics in the Shoe Industry (1971) (Elsevier). (10) Hole, L. G. and Keech, B. SATRA Bulletin March (1968). (11) Hole, L. G. and Keech, B. Proceedings of the Xlth Conference of the International Union of Leather Chemists Societies, London (1969). (12) Blazaj, J. A. Proceedings of the Xlth Conference of the International Union of Leather Chemists Societies, London (1969). (13) Hole, L. G. and Popplewell, D. Proceedings of the XIIth Conference of the International Union of Leather Chemists Societies, Prague (1971). (14) Eiselle, C. W. and Eichelberger, L. Proc. Soc. Exp. Biol. Med. 58 97 (1945). (15) Wright, V. and Elden, H. R. Biophysicalproperties of the skin (1971) (Wiley-Interscience). (16) Ktmo, Y. Human perspiration (1956) (C. C. Thomas). (17) Pettit, D. J. Soc. Leather Trades Chemists 45 415 (1961) (18) English, M.P. and Gibson, M.D. Brit. Med. J. 1 1442-1446 (1959). (19) English, M.P., Gibson, M.D. and Warin, R. P. Brit. Med. J. 1 1083-1089 (1961). (20) English, M. P and Wethered, R. R. Brit. Med. J. 3 136--139 (1967). (21) English, M. P and Turvey, J. Brit. Med. J. 4 228-230 (1968). (22) Hall, F. R. Arch. Dermatol. 74 306 (1956). (23) Lamberg, S. I. Arch. Dermatol. 100 10-11 (1969). (24) Gill, K. A. and Buckles, L. J. Arch. DerrnatoL 98 7-11 (1968). (25) Calnan, C. D. and Sarkany, L. Trans. St. John's Hosp. Dermatol. Soc. 43 8-26 (1959). (26) Jordan, J. W. Arch. Dermatol. syphilol. 62 671 (1950).