ESSENTIAL OILS AND THEIR CONSTITUENTS. XXV. 167 Scope of Technique Thin layer chromatography has been applied successfully to the characterization of essential oils. The method is of particular value in routine analyses because of its simplicity. It also holds great promise for detailed taxonomic and phylogenetic researches. Coupled with other physicochemical techniques, e.g., column and gas chromatography (2, 6, 7) it offers unique avenues for investigating the composition of essential oils and related products on a microchemical scale. (Received June 26, 1964) ACKNOWLEDGMENTS The authors acknowledge the generous assistance given by many laboratories and suppliers in providing authentic samples for this study and wish to thank the following: For essential oils. Association de Productores de Aceites Esenciales Guatemala, C.A. Bureau of Commodity, Inspection and Quarantine, Republic of China, Taipei, Taiwan Charabot & Co., Grasse, France Colgate Palmolive Company, Jersey City, U.S.A. Dierberger Oleos Essentials, S.A., S•o Paulo, Brazil Excel Traders, Bombay, India Firmenich & Cie, Geneva, Switzerland N.V. Chemisehe Fabriek "Flebo," Hoogezand, Holland Forest Research Institute, Dehra Dun, India Fritzsche Brothers Inc., New York, U.S.A. H.B. Technologi- cal Institute, Kanpur, India Indian Standards Institution, New Delhi, India International Flavours and Fragrances, Inc., New York, U.S.A. Wm. Leman, Inc., Bremen, Ind., U.S.A. Magnus, Mabee and Reynard, Inc., N.Y., U.S.A. McKesson and Robbins, Ltd., London, England Manaunlal Ramnarain, Kannauj, India Mane Fils, Inc., New York, U.S.A. N.V. Chemisehe Fabriek "Naarden", Naarden, Holland National Chemical Laboratory, Poona, India Pierre Chauvet & Co., Seillans, France Polak's Frutal Works, Inc., Middletown, N.Y., U.S.A. Purandad Oil Plantations, Dehra Dun, India Regional Re- search LaBoratory, Hyderabad, India P. Robertet, 1no., New York, U.S.A. Roure-Bertrand Fils et Justin Dupont, Argenteuil, France Stafford Allen and Sons, Ltd., England Takasago Perfumery Co., Ltd., Tokyo, Japan C.F. Ten Eyck & Co., Burbank, Calif., U.S.A. A.M. Todd Co., Kalamazoo, Mich., U.S.A. Tropical Products Institute, London, England University of Puerto Rico, Mayaguez, Puerto Rico. For essential oil constituents. Fritzsche Brothers, Inc., New York, U.S.A. The Glidden Company, Jacksonville, Fla., U.S.A. Hoffmann-

168 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS LaRoche, Inc., Nutley, N.J., U.S.A. International Flavours and Fra- grances, Inc., New York, U.S.A. A.M. Todd Company, Kalamazoo, Mich., U.S.A. The Trubek Laboratories, Inc., East Rutherford, N.J., U.S.A. The authors are indebted also to Dr. Ernest Guenther, Fritzsche Brothers, Inc., New York, U.S.A., and Dr. Sadgopal, Indian Standards Institution, New Delhi, India, for their interest and support of this study. REFERENCES (1) Sahasrabudhe, M. R., Chemist-Analyst, 52, 83 (1963). (2) Nigam, I. C., and Levi, L., J. Pharrn. Sci., 53, 1008 (1964). (3) Naves, Y. R., and Grampoloff, A. V., Cornpt. Rend., 249, 306 (1959) Bull. Soc. Chirn. France, 27• 37 (1960). (4) •Nigam, M. C., Nigam, I. C., and Levi, L., Can. J. Chern., 43, 521 (1964). (5) Rogers, Jr., J. A., Proc. Sci. Sect., Toilet Goods Assoc., 32, 9 (1959). (6) Nigam, I. C., Sahasrabudhe, M. R., and Levi, L., Can. J. Chern., 41, 153,5 (1963). (7) Nigam, I. C., and Levi, L., Ibid., 41, 1726 (1963).