18 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS an easy way of separating the epidermis from the corium, by simply stretch- ing the skin and scraping off the epidermis without contaminating it with dermal tissue (16) a method for separating dried epidermal powder into cellular and keratinous fractions by differential centrifugation (17) and the isolation and purification of epidermal proteins by precipitation at the isoelectric point, dialysis, and chromatographic absorption (8, 9). The hope for a clearer understanding of epidermal differentiation through the isolation and analysis of well-defined epidermal fractions is, thus, within the realm of realization. Even with these improvements, the task is tedious and time-consuming, because of the small quantities of tissue available. In our laboratory less than 10 gm. wet weight of epidermis was obtained from almost the entire body surface of a newborn infant (8) the average weight of epidermis covering 1 cm. sq. is 1.8 mg. dry weight (4). or about 5 rag. wet weight (18). In spite of these difficulties, research of epidermal proteins is being actively pursued in several research centers and it is likely that these studies will ultimately shed more light on the most important and basic process of cutaneous metabolism. B•BL•OGRAPI4¾ (1) Rothman, S., "Physiology and Biochemistry of the Skin," Chicago, University of Chicago Press (1954). (2) Wassermann, F.,/ira. •./inat., 94, 399 (1954). (3) Pinkus, F., "Handb. der Haut- u. Geschlkrkh," Vol. 1, Pt. 1, Berlin, J. Springer (1927). (4) Maltoltsy, A. G., personal communication. (5) Mescon, H., et al., to be published. (6) Van Scott, E. J., and Flesch, P.,/irch. Dermatol. and SyphiloL, 70, 141 (1954). (7) Rudall, K. M.,/idvances in Protein Chem., 7, 253 (1952). (8) Anderson, D. S., personal communication. (9) Matoltsy, A. G., to be published. (10) Block, R. J., )t. Soc. Cosmetic Chem., 2, 235 (1951). (11) Van Scott, E. J., and Flesch, P., Science, 119, 70 (1954). (12) Giroud, A., and Leblond, C. P.,/inn. N.Y./icad. Sci., 53, 613 (1951). (13) Barrnett, R. J., in press. (14) Flesch, P., Brit. y. Dermatol., to be published. (15) Rothman, S., Rubin, L., and Houston, M.,/irch. Dermatol. and SyphiloL, 48, 400 (1943). (16) Van Scott, E. J., Investigative DermatoL, 18, 377 (1952). (17) Flesch, P., Proc. Soc. Exptl. Biol. Med., 85, 483 (1954). (18) Flesch, P., unpublished data. zlcknowledgment: The author wishes to express his thanks to Dr. D. S. Anderson for her help in the preparation of this paper.

THE USES AND NEWER APPLICATIONS OF THE SILICONE COMPOUNDS IN DERMATOLOGY AND COSMETICS* By IRWIN I. LuBowE, M.D. New York 21, N.Y. T• SILICONE fluids (dimethylpolysiloxanes) have been introduced into the field of dermatology and cosmetics during recent years because of their unusual chemical and pharmaceutical properties, particularly their ability to act as cutaneous protectants against primary irritating and allergenic sensitizing substances which may come in contact with the skin during occupational and household exposure. The silicone fluids are characterized by little change in viscosity with variations of temperature. When exposed to high temperatures, they possess low volatility and excellent stability to oxidative attack. The following properties indicate a wide range of usefulness in their ap- plication in the dermatological and cosmetic specialties. They are clear, colorless fluids, are easily emulsified, and there is no tendency toward rancidity. Their low surface tension is helpful in the incorporation in pharmaceutical formulation, and aids in their adsorption and cohesiveness to the skin surface, by the formation of a thin adherent film. They are water repellent, invisible when applied to the skin, do not interfere with tactile sensation, and do not disturb the normal function of perspiration or sebaceous secretion. The solubilities of the Velvasil Silicone fluids} vary with the chemical structure of the solute and they are not dispersible in aqueous solutions. Pharmacological and toxicological studies have demonstrated their safety when ingested or applied topically to animal and human integument. Tajkowski and Reilly (1) have suggested formulations of the silicones in various dermatological and cosmetic applications, as protective skin creams and lotions, baby creams and lotions, sunscreening preparations, hair dressings, ointment bases, lip pomade, lipstick bases, and emollient creams. The initial use of silicones as skin protectants was described by Talbot (2) * Presented at the December 9, 1954, Meeting, New York City. t The Velvasil fluids were furnished by the Silicone Division of the General Electric Co., Waterford, N.Y.