112 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The expert fulfills a very useful function with his ability to describe and classify sensory properties. He may be able to describe in detail how Chanel #5 differs from a cheap imitation. However, the expert cannot tell whether the mass market would prefer it for its characteristics alone if it were available under another name at dime store prices. Only a con- sumer panel can truly speak for the likes and dislikes of consumers. The data on precision, as presented in this paper, should not be dis- couraging to the use of consumer panels, but only to the use of small panels. Consumer data, as the foregoing tables show, offers reliability and repre- sentativehess to the extent that we are willling to pay for it. There are no bargains in the sense of obtaining just as good results from small numbers of people as from large. The precision of the result can be predicted in advance from very simple and straightforward statistical concepts. Where the ultimate research objective is consumer satisfaction, there is no substitute for guidance direct from the consumer himself. As we all know, the consumer will eventually have his own way. BIBLIOGRAPHY (1) Brownlee, K. A., "Industrial Experimentation," Chemical Publishing Co. (1952). (2) Dixon, W. J., and Massey, F. J., Jr., "Introduction to Statistical Analysis," McGraw-Hill (1951). (3) Fisher, R. A., "Statistical Methods for Research Workers," Oliver & Boyd l.td. (1948). (4) Guilford, J.P., "Psychometric Methods," McGraw-Hill (1936). DISCUSSION MR. LOgOYELLOW: I have a question in reference to Table 2 and Table 3, whether only a choice was offered to the panelists, or whether they were permitted to express a "no prefer- ence." MR. ISHLER: Yes, they were. What we have done with all of these data--you could get into a long discussion on that, too--is to divide the "no preference" votes equally between the two samples there, by your two percentages, the preference for one sample, always adding up to 100. I should not claim that this is the proper way to do it, but it is one way, and it is useful in many respects.

TOXIC AND ALLERGIC COMPLICATIONS OF HAIR DYES* By SAMUEL M. PECK, M.D. New York, N.Y. ]'HERE ARE THREE classes of hair dyes: the metallic dyes, the vegetable dyes, and the synthetic organic dyes. In approximately 95 per cent of the hair dyeing operations, both professionally carried out in beauty parlors as well as in the home, there is used a paraphenylenediamine dye or some modification of para. The remaining 5 per cent are either carried out with natural products or with the compound henna dyes. Many of the compound henna dyes contain small amounts of paraphenylenedia- mine and metallic salts to obtain variations in shades required. The active principle in henna dyes is 2-hydroxy-l,4-naphthaquinone. It is recognized that henna is practically blameless as a local or systemic toxic agent. It has verv rarely, if at all, been incriminated as a sensi- tizer. Henna hair dyes have not become popular because there is an in- sufficient range of colors produced with this dyeing material and the color is practically limited to an auburn with a reddish tone. In addition, henna has the distinct disadvantage after repeated applications of giving a rather brassy, unnatural looking color to the hair. The metallic hair dyes are very rarely used in modern hair dyeing. Most of the dyes are compounds of lead and rarely those of silver, copper, iron, bismuth, etc. It is believed that the color that is produced by these metal- lic compounds is due to a reaction between the sulfur in the keratin and the metallic salts so that we have a production of the sulfide of the metal. It is probable, however, that the keratin also acts as a reducing agent caus- ing a precipitation of the black metal oxide. Their use is not satisfactory because of the limitation in range of colors and because the pigment produced is deposited on the outside of the hair shaft resulting in an un- natural metallic appearance. Metallic dyes also degrade the hair and interfere with subsequent permanent waving. The discussion in this paper will be limited to the consideration of the toxicity of the para and allied dyes. * Presented at the December 10, 1953, Meeting of the American Academy of Dermatology, Chicago, Ill. 113