COMPARISON OF BEARD AND SCALP HAIR 365 Figure 5. Transmission electron micrographs of Caucasian beard and scalp hair cross-sections of the same subject. Magnification 915 x. c. Cross- Sectional Area Measurement Cross-sections of hair fibers, magnified 300x on photographs, were traced with a planimeter for area determination. For each beard or scalp hair type, measurements of at least 12 cross-sections were taken (six fibers each from two individuals). 5. Transmission Electron Microscopy ( TEM ) Intact scalp and beard hairs were placed in flat silicon rubber molds and embedded in Durcupan © Fluka Epoxy resin at 60øC. Prior to embedment, the hairs were oriented for

366 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 4. Transmission electron micrographs of Chinese beard and scalp hair cross-sections of the same subject. Magnification 915 x. M: Medula CO: Cortex C: Cuticle. Table I Diameters of Caucasian Beard and Scalp Hair Diameter a (tim) Subject Beard Hair Scalp Hair Beard/Scalp CMT 143.7 _+ 6.9 72.0 _+ 2.9 2.00 DLS 124.6 _+ 8.7 79.9 -+ 1.1 1.56 GHS 131.3 _+ 3.2 72.9 _+ 1.7 1.80 JGY 123.3 _+ 5.7 71.4 _+ 15.1 1.73 LHE 107.0 _+ 3.3 64.3 _+ 4.6 1.66 MDG 126.9 _+ 11.3 58.7 _+ 7.6 2.16 NHS 120.8 _+ 11.3 55.7 _+ 2.9 2.17 PHY 113.4 _+ 5.6 68.9 _+ 8.9 1.65 PKA 139.1 _+ 20.8 86.6 + 4.5 1.61 SDN 125.6 _+ 13.1 65.3 +- 11.0 1.92 Average 125.6 _+ 10.9 69.6 + 9.3 1.83 aFive beard and five scalp hairs from each subject were measured at five locations along the fiber. At each location the fiber was rotated and measurements taken at 0% 45% 90% 135% and 180 ø axial rotation. Diameter values for the five fibers were averaged and reported here along with standard deviations from fiber to fiber.