IRON PIGMENTS OF HAIR AND FEATHERS 681 (8) Flesch, P., Esoda, E. J., and Katz, S. A., The iron pigment of red hair and feathers, Ibid., 47, 595-7 (December 1966). (4) Zelickson, A. S., Ultrastructure of Normal and Abnormal Skin, Lea & Febiger, Phila- delphia, Pa., 1967, p. 169. (5) Fitzpatrick, T. B., et al., The Nature of Hair Pigment, in Montagna, W., and Ellis, R. A., Biology of Hair Growth, Academic Press, New York, N.Y., 1958, pp. 255-301. (6) Aisen, P., Aasa, R., Malmstr6m, B. G., and Vanngard, T., Bicarbonate and the binding of iron to transferrim J. Biol. Chem., 242, 2484-90 (May 25, 1967). (7) Warner, R. C., and Weber, 1., The metal combining power of conalbumin, J. Am. Chem. Soc., 75, 5094-101 (October 20, 1953). (8) Fukuyama, K., and Epstein, W. L., Epidermal keratinization: Localization of iso- topically labeled amino acids, J. Invest. Dermatol., 47,551--60 (December 1966). (9) Flesch, P., Esoda, E. J., and Katz, S. A., The color of red hair, J. Soc. Cosmetic Chemists, 18, 777-84 (December 1967). (10) Boldt, P., Trichosiderin, ein Pigment aus roten Haaren, Naturwissenschaften, 51, 265 (June 1964). (11) Boldt, P., and Hermstedt, E., Pyrrotrichole, eine Gruppe farbiger Verbindungen aus rotem Menschenhaar, Z. Naturforsch., 22b, 718-22 (July 1967). (12) Flesch, P., and Esoda, E. J., The pigmentation of red hair, Dermatology Digest, 7, 49-44 (1968).

J. Soc. Cosmetic Chemists, 19, 683-697 (Sept. 16, 1968) Effect of Initial Surfactant Locations on the Viscosity of Emulsions TONG JOE LIN, Ph.D.* Presented December 6, 1967, New York City Synopsis--Viscosities of emulsions immediately following homogenization were studied as a function of HLB and the initial surfactant locations. Keeping the total surfactant concen- tration constant, the ratios of the initial concentration of the hydrophilic surfactant to that of the lipophilic surfactant in each phase were varied. The experimental results indicate that the initial locations of the surfactants not only affect the initial viscosity of the emulsions but also the emulsion stability, particle size distribution, and emulsion type as well. INTRODUCTION There are literally unlimited ways by which a given emulsion can be prepared (1, 2). Unquestionably, the method of preparation has a great influence on the physical properties of the finished emulsion. Stanko et al. (3) conducted a series of expehments with a mineral oil emulsion stabilized with nonionic surfactants. They discovered that the method of addition, the rate of addition, and the temperature of each phase at the time of emulsification all had some effects on the droplet size distribution, viscosity, and the emulsion stability. Using a two-level fractional factohal design, Benson et al. (4) con- ducted an extensive investigation of six preparative variables including: order of addition, emulsifier location, emulsifier concentration, propor- tion of water, emulsification temperature, and type of agitation. Four oils were used and thirteen different surfactants were employed in their investigation. They discovered that the chemical and physical nature * Max Factor & Co., 1655 N. McCadden Place, Hollywood, Calif. 90028. 68.3