DIRECTORY OF MEMBERSHIP Mr. Paul A. Thomasset, Thomasset Colors, Inc., 338 Wilson Avenue, Building 92, Newark 5, New Jersey. Dr. P. Curt Wimmer, 7228 Ingram Street, Forrest Hills, New York. Mr. Verling M. Votaw, 67 Reilly Road, Wyoming 15, Ohio. Mr. Walter E. Waide, Jr., John H. Breck, Cmnpany, 115 Dwight Street, Springfield, Massachusetts. Mr. William Howard Walker, 326 Eugenia Street, Lombard, Illinois. Miss Florence E. Wall, 210 East 68th Street, New York 17, New York. D•. Juliu• Wetterhahn, 143 - 23 71st Avenue, Kew Garden Hill, Long Island 1, New York. Mr. Carl G. Westerberg, Gini Products, 432 Valley Boulevard, San Gabriel, California. Mr. Herman James White, 17603 Roy Street, Lansing, Illinois. Mr. Nathan Winarick, 2910 Grand Concourse, Bronx, New York, New York. Dr. Henry ]. Wing, 16 Grandview Avenue, Stamford, Connecticut. Mr. Louis 1I. Wolfson, 943 Cross Avenue, Elizabeth 3, New Jersey. Mr. Walter Wynnc, Givaudan - Delawanna, Inc., 330 West q2nd Street, New York, New York. 51r. Wilbur A. Young, Warwick Chem. Co., Div. Sun., Chemical Corporation, Wood River Junction, Rhode Island. Mr. Ralph C. Zehncr, 153 East Chester Street, Valley Stream, Long Island, New York. Mr. Samuel Zuckerman, 18 Dubonnet Road, ¾alley Stream, Long Island, New York. Mr. Ross C. Whitman, Route 8, Ramsey County, White Bear Lake, Minnesota. Mr. Hyman W. Zussman, 225 Morris Avenue, Providence 6, Rhode Island. Mr. Kurt Hans Wielick, 2204 Murray Street, Philadelphia, Pennsylvania. Mr. Christian F. Wight, 5 Quintard Drive, Port Chester, New York. OVERSEAS MEMBERS Mr. Oscar Alonso, Crusellasy Cia., S.A., P.O. Box 301, Havana, Cuba. 207

JOURNAL OF THE SOCIETY OF COSi•IETIC CHEMISTS' Mr. Erhard S. Alterthum, Dermacult, Limited, 30 Adderly Street, P.O. Box 2362, Cape Town, South Africa. Mr. John C. James, United - Rexall Drug Co., Ltd., 68 Broadview Av.enue, Toronto 8, Ontario, Canada. Mr. Cecil C. Clark, The Anglo. Canadian Drug Co., Ltd., 99 Simcoe Street, South, Oshawa, Ontario, Canada. Mr. Alec Rimer, 17 Belmont Court, Banket Street, Hillbrow, Johannesburg, South Africa. Mr. Alberto E. L. Codina, Pond's Argentina S.R.L., Tucuman 2341, Buenos Aires, Argentina. Dr. Sadgopal, c/o Chemistry Branch, Forest Research Institute, P.O. New Forest, Dehra Dun, India. Mr. Stanley Gurland, P.O. Box 1751, Cape Town, South Africa. Mr. Herbert E. Szama, Avertida Santa Fe 3091, Buenos Aires, Argentina. STABILITY OF COSMETIC EMULSION5 (Concluded from page 197) as part of such a test. Finally, the possibility of a spon- taneous phase inversion occuring at some future time should be guarded against. Whether a given emulsion will be of the oil-in-water or the water-in-oil type depends on the type of emulsifier, the emulsion ingredients, the proportions of the two phases, and other factors. Any given emulsion may be near enough to instability so that some change in storage conditions may result in a phase inversion. Once a formula has been tenta• t. ively adopted, its stability against this type of change can be tested by making a series of small alterations in the formula. These alterations should include 'changes in the proportions of emulsifier, con- tinuous phase, and disperse phase. If the product is to be stable in re- gard to inversion all the altered samples should turn out to be of the same phase type. If some of the samples show inversions, their com- positions will indicate the change to be made in the original formula to avoid this change. It is hoped that this description of emulsion testing and testing theory will prove to be helpful to others who work with emulsions. The author gra.tefully acknowl- edges the helpful suggestions ooe Mr. E. J. Latos of Colburn Labora- tories, Inc. and of Dr. Herbert Sanders of Ninol Laboratories. (Paper presented at the' September, 1950, meeting of the Chicago Section, Society of Cosmetic Chemists, U.S.A.) 208