768 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Society of Cosmetic Chemists Journal Advertising takes your message straight to the Chemists of the Cosmetic Industry For information oclclress: Editorial Assistant Society of Cosmetic Chemists 761 North Valley Chase Road Bloomfield Hills, Michigan 48013

J. Soc. Cosmetic Chemists, 17, 769-787 (1966) Caucasian Hair, Negro Hair, and Wool: Similarities and Differences J. MENKART, Ph.D., L..1. WOLFRAM, Ph.D., and IRENE MAO, M.D.* Presented May 10, 196'6, New York City Synopsis--Caucasian hair, Negro hair, and Lincoln wool are compared in ternis of physical structure, mechanical properties, chemical composition, and rate of reaction with various re- agents. Several significant differences are found between wool and the two hair samples. The principal one is the extent of crosslinking, which is greater in the hair, as indicated by higher sulfur and cystine contents, and a higher proportion of the material found in the •-keratose fraction after oxidation. The heavier crosslinking is reflected in greater resistance to attack by hot acid and in slower reduction by thioglycolate or sulfite solutions. The main difference between Caucasian and Negro hair is in fiber geometry the Cau- casian fiber approximates a cylinder, the Negro a twisted oval rod. In their physical and chemical properties, the two fibers are very similar. I. INTRODUCTION Human hair, the wool of the sheep, and the hairs of the various goat species of textile importance (angora, cashmere) are closely related to each other morphologically, chemically, and physically. The simi- larities between them are, in most respects, so close that fiber investi- gators at one time developed the habit of treating them as almost inter- changeable. It became customary to employ human hair for studies of fiber mechanical properties directed to the understanding of wool the following quotation (1) is typical of numerous papers of the 30's and early 40's: "Human hair was selected for use in preference to wool * Harris Research Laboratories, Inc., Gillette Research Institute, Washington, D. C. 20007. 769