192 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS With most substances the genetic "state of preparedness" or susceptibility plays a major part. Only a proportion of the population at risk will become sensitized when all are equally exposed. How this susceptibility is deter- mined is not known. That it exists can be demonstrated in both man and in guinea pigs. I believe that dermatitis from tetrachlorosalicylanilide has been a problem in England only because the soaps containing it have been used by such a large number of people, and almost all of the patients have been among those who use the soap with the largest sales. It is interesting that I have not seen, and do not know of any instance of more than one proven case in a family, even though the same soap has been used by the whole household. I have heard of alleged familial cases, but have not had the opportunity to prove any of them. From the study of these patients, dermatological knowledge has been enriched, but, as usually happens, many further problems have been posed. Perhaps the most pertinent one is this: Could any animal or human studies have detected the photo-contact sensitizing property of tetrachloro- salicylanilide sufficiently accurately to have recommended to the soap manufacturers that it should not have been used ? In the present state of knowledge and experience, I doubt it. ACIr•OWLEDGMENTS I should like to thank Dr. G. C. Wells, Dr. R. R. M. Harman, Dr. D. S. Wilkinson, and many other dermatological colleagues for their help during this study. (Received: 6th April 19•oe) REFERENCES Wilkinson, D.S. Brit. J. Dermatol. 73 218 (1961) Hjorth, N. Eczematous •lllergy to Balsams (1961) (Munksgaard, Copenhagen) Hurst, A., Stuttard, L. W., and Woodroffe, R. C. S. J. Hyg. 58 159 (1960) Lennon, W. J., Furia, T. E., and Zussman, H.W. Soap Chem. Specialties 36 51 (March 1960) ibid 53 (April 1960)

QUESTION AND ANSWER 103 QUESTION AND ANSWER At a scientific meeting of the Society held on 23rd March 1961, questions were put by the audience to a panel consisting of Mr. E. K. Clarke, Dr. R. H. Marriott, Mr. T. P. McLaughlin and Mr. I. Pickthalh The proceedings were recorded and subsequently edited by Dr. H. W. Hibbott (chairman of the meeting). Question 1. What are the best laboratory methods of shampoo evalua- tion and how can such methods be correlated with consumer assessment ? Answer: There is really no substitute for subjective tests for shampoo assessment. Moreover, the tests should be carried out in a reasonably standard manner with independent observers, and enough tests done to assure some statistical treatment of the results. In screening the many detergents available and finding the desirable concentrations of suitable ones, laboratory methods must be used. Deter- mination of actual grease removal gives one type of assessment. In assess- ment related to consumer acceptance, some work has been carried out, designed to find what happens in the shampooing process and after--the factors responsible for the final condition of the hair such as gloss and "softness of handle". That work, reported in the Journal of the Textile Institute, is mainly concerned with the state of hair after washing or other treatments. In such conditions, cortex cells and cuticle cells may be broken down from the hair in amounts proportional to the amount of damage sustained by the hair. By a quantitative count method, the ratio of cortex cells to cuticle cells will give an assessment of effect of shampoos which corresponds closely to corresponding subjective opinions. Despite this, usage tests must still play a large part in consumer accept- ance. Moreover, personal usage tests are to be preferred to salon testing. An expert hairdresser can get good results from a poor shampoo. The consumer, the self-user, with eyes closed during the operation, does not even see the lather produced on the hair but makes an assessment by the feel of the lather. Question oe. Are antioxidants of any value in preventing deterioration on ageing of perfume, particularly those containing solubilisers ? Answer: Antioxidants are of use but on the other hand a perfume usually carries its own antioxidant. Some of the most efficient anti- oxidants are phenolic compounds of which eugenol is a good example. In fact, traces of eugenol are often added to aldehydic raw material to prevent oxidation. It should not be necessary to deliberately add an antioxidant to a perfume in alcoholic solution. Indeed, a well-made