18 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS but very interesting trees, as instanced by A verrhoa c•rambola, the kumrunga , which grows to a height of about 16 feet and is remarkable first for the beauty of its crowded clusters of small pale rose-coloured ribes-like flowers which produce fruit the size of a lemon. These, when well-ripened, have a strong and agreeable quince-like scent and something of a nutty peach flavour. Belonging to the same genus is A. Bilimbi, the bimbling or cucum- ber tree, which flowers in a similar way to the above, but the fruit is of the form and size of a gherkin, with a smooth, thin, pale green, translucent rind, like that of the white grape. When ripe it is as soft as butter, with a flavour like an unripe gooseberry and afterwards acquiring the aroma of strawberries. SUMMARY It is evident from the statistical data that Geranium and/or geraniol are extensively used as the basis for the formulation of all kinds of artificial floral oils and fancy bouquets while the rose odour is particular to the Pelargoniums, which occupy the dominant position in the Family, and with one exception the remaining items recorded may be regarded as of minor importance. This study has directed attention to one of the modest members of the family around which some genera from other N.O.s have been arranged, a sector which may perhaps conveniently be named as the Balsamina, and from this group at some time there may become available a companion to clary sage. Regarding this latter herb, with its musky-amber character, W. A. Poucher, in Volume I, makes a very interesting remark, for he says: "It is this aroma which is so distinctive in fine quality essential oils, such as certain varieties of geranium and neroli, and which is absent in synthetic aromatic chemicals, as instanced by geraniol and nerol (in comparison)." Although we have observed the balsamic-labdanum redolence to be an integral part in many of the pelargonium oils, yet by removing this somewhat heavy nuance and replacing it with an Essence of Balsamina, some remarkably interesting results might, in my view, become apparent. REFERENCES • Maurer, E. S., Th• oess•ntials of P•rfum• Compounding, Part 2 of which, "The Natural Orders," is currently being serialised in Soap, P•rf•ery • ½os•tics. • Ibid., a series in which this paper will eventually take its place as the nineteenth essay. • Ibid., July, 1956.

'GLYCERIN AS A CONSTITUENT OF COSMETICS AND TOILET PREPARATIONS An Attempt at Reappraisal by F. V. WELLS* The characteristic properties are critically discussed and the manner in which these properties contribute to its employment in cosmetics. GLYCERIN, called by its Swedish discoverer, Carl Wilhelm Scheele, "the sweet principle of fats," is a substance noted above all else for its exceptional physical versatility a property that is enhanced and accentuated by chemi- cal stability, •esthetic appeal, relatively low cost and a wide range of com- patibility with other materials. I have referred elsewhere to many of the properties and cosmetic applications of glycerin, • and an excellent review of the subject has been written by Kalish.' Other papers and articles to which reference may use- fully be made in this connection include those of Pickthall,' Reckless? Bragg? Stetson,, and Chadwick and Pears.' An informative review of glycerin as a humectant is to be found in the revised' first volume of Harry's work,' and much information of a general character is contained in the broad survey, "Glycerin: its Industrial and Commercial Applications," published in 1945,' and Lawrie's book on glycerin and the glycols. •o While cosmetic chemists do not need to be told, at this rather late hour of the day, that glycerin is one of their most valuable and versatile raw materials, it is nevertheless opportune, and may prove profitable, I think, to attempt a contemporary reappraisal of its pi-operties and uses. The present survey represents, however imperfectly, such an attempt to consider one by one the several and diverse properties that are uniquely contained in this familiar material, and the ways in which they are utili3ed in the cosmetic industry. Probably the most important property of glycerin, so far as the cosmetic chemist is concerned, is its hygroscopicity, or power to absorb and retain moisture. W.C. Griffin and co-workers n have further defined two aspects of hygroscopicity, namely, equilibrium hygroscopicity, which is the state or condition that exists when an aqueous solution of the humectant or hygro- scopic agent will neither gain nor lose water at a given humidity (RH), and dynamic hygroscopicity, or the relative speed with which a humectant or its aqueous solution will gain or lose moisture while approaching equilibrium. In addition to these two factors, certain other properties must be taken into account when selecting a humectant (or moisture content-stabilising agent) for cosmetic use. It is, for example, deskable that the humectant should be characterised by low volatility, although I do not agree with Griffin * Honorary Member Cosmetic Consultant, London. 19