JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS in the rapid determination of many substances, particularly when they are present only in small concentrations. ACKNOWLEDGMENT The author wishes to express his thanks to the Directors of County Laboratories, Ltd., for permission to publish this paper. REFERENCES • Clark, G. R., y. Soc. Cos. Cicero., 1951, 2,290. '" Moore & Stein, •f. t•iol. Chem., 1948, 176, 367. a Bolton & Marshall, Soap and Sanitary Chemicals, 1949, 25, 129. • Hawksley, B.C.U.t?./t., 1944, 8, 245 (Review). • Lederer & Tchen, Bull. Soc. Chim. Biol., 1945, 27, 419, via •f.C.S., 1949, 2121 6 Anal. Meth. Comm. Rep. Analyst, 1954, 79, 397. ? Fogh, Rasmussen & Skadhauge, Anal. Chem., 1954, 26,392. /t Lecture delivered to the Society on 5th ]kIarch, •r954 TALKING OF PERFUMES AGAIN By J. PICKTHAnr, F.R.I.C.* I•TRODUCTION THERE MUST be a number of non-technical members of this audience who are interested in perfumes and who would like to know something of their nature and the way in which they are employed. Further, many of our technical members use or handle perfumes without, perhaps, having had the opportunity of giving the subject a comprehensive study. Nobody would doubt the importance of perfumes in the cosmetic and associated industries: they are as important to success as attractive packing and presentation. One might add that a perfume continues to please the buyer long after the appeal of the container has faded. Most people in this world are favourably impressed by a good perfume, although naturally preferences are widely divergent. Even the men, although often reluctant to admit it, are influenced by odour. My aim this evening is to introduce perfumery to those who know it only by name, to assist those with a working knowledge and to interest the experts. Perfumery, although one of the oldest arts of expression, is young in a scientific sense. We know little of the mode of action of odour perception and much work of a scientific nature remains to be undertaken before we can develop theories. Frankly, I do not believe that the many classifications offered have greatly helped either the established or the budding perfumer. The well-known numerical classification, I am afraid, confuses without offering a starting-point as a language or even an alphabet for perfumers. It is this lack of descriptive words that makes perfumery so difficult to * Polak & Schwarz (England) Ltd., Enfield, Middx. 182

TALKING OF PERFUMES AGAIN discuss. A layman with a tune running through his mind might hum or whistle the tune and enable a pianist to record his impressions. One could likewise describe a scene or subject to a painter and comment upon colour depths and tones so that the impression could be translated and recorded. When one acknowledged perfumer speaks to another equally accomplished in the art, even they are sadly deficient in descriptive phrases and the jargon they employ would be Greek to an outsider. We speak of top, middle and back notes, intended to convey a scale of diminishing volatility of the con- stituents. This same scale is also employed on a weight basis•light, medium and heavy notes. We speak of warmth of odour, but what does that mean to the layman, and just how closely would two perfumers agree on a tempera- ture scale in describing a range of chemicals or oils ? We limit our use of colour comparisons to green, a word intended to be descriptive of odours associated mainly with leaves, but how green is my Lily of the Valley ? We make half-hearted use of linear measurements and talk vaguely of "depth." Naturally, we bring "aromatic," "aldehydic," "phenolic," "fatty," "burnt," "leathery" and a host of partially descriptive names into our con- versation, but again the values are vague and uninformative to the outsider and far from definite to the expert. After all, there are a great number of aldehydes, to name but one word from our dictionary. We come nearer to reality when we speak in terms of flowers, for despite the variety of odours to be found in one floral type, the naming of Lavender, Rose or Carnation is certainly descriptive, although even the use of floral names is limited to a relatively few well-known types. This frustrating lack of vocabulary brings to mind a story which I am sure will be familiar to all members of the audience. It concerns Noah and his Ark and, incidentally, Noah must have had his problems where odours are concerned. The story goes that Noah named his animals with little or no effort, until he came to the frog, which completely stumped him. Asking his wife's opinion, she immediately said, "Call it a frog," and when Noah asked why this particular name, Mrs. Noah replied, "Because it looks like a frog." Admitting, therefore, our lack of vocabulary, how are we to rectify this inadequacy ? Obviously, by establishing a scale of units which will accurately and precisely describe a given odour, but before such a step can be taken we have still to investigate and understand just exactly what odour is and how it works. ODOUR PERCEPTION This phenomenon constitutes a scientific miracle. The ear and eye cater for a relatively small number of vibrations but the nose can receive and identify an apparently unlimited number of different odours or, at any rate, relay messages which the brain translates as differences. Many theories on 183