370 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS RESULTS AND DISCUSSION 1. Fiber Morphology Light and transmission electron microscopy studies showed that scalp fibers had significantly smaller cross-sectional areas and were generally circular-elliptical, whereas facial hairs were asymmetrical, in the oblong, kidney, and trilobal configurations (Figures 1-4). In the ten Caucasian individuals, the diameter of beard hair was larger than that of scalp hair (Table I, Figures 2-4). It has to be noted, however, that there was a considerable variation in cross-sectional size and shape along the hair fiber, among fibers from the same individual, and among fibers from individuals within the same race. The variation can be illustrated by the range of average diameters and ellipticity indices (Tables I-II). Differences were larger in beard then in scalp hair. C.- D Figure 7. Scanning electron micrographs of typical Chinese scalp hair (A) and beard hairs (B, C, D). Magnification 400 x.

COMPARISON OF BEARD AND SCALP HAIR 371 Table III Characterization of Scalp and Beard Hair of Three Racial Groups Fiber Type a Cross-sectional Area b Major Axis Minor Axis (/am 2) (/am) (/am) Ellipticity Index c Caucasian Scalp 6,300 _+ 1000 110.8 _+ 11.0 67.8 _+ 23.8 1.6 _+ 0.3 Beard 10,700 _+ 1400 164.4 +_ 14.1 79.7 -+ 16.8 2.1 _+ 0.5 Chinese Scalp 7,600 _+ 2300 106.4 _+ 18.3 82.8 _+ 10.2 1.3 _+ 0.2 Beard 14,100 _+ 3900 171.3 -+ 29.3 94.4 _+ 24.1 1.9 -+ 0.5 Negro Scalp 6,200 +_ 1200 118.8 _+ 15.2 66.1 _+ 15.1 1.9 -+ 0.4 Beard 12,900 _+ 4400 172.7 _+ 31.1 84.6 _+ 20.2 2.1 +_ 0.4 aFor each hair type twelve cross-sections were prepared, six fibers each from two individuals. bindirect measurement from photographs using planimeter. CRatio of the major axis to the minor axis. Scanning electron microscopy studies also confirmed the differences in fiber size and shape between beard and scalp hair in all three racial groups. Representative scanning electron micrographs are shown in Figures 5-7. Caucasian scalp hairs were round or oval in cross-section, while the beard hairs usually had more asymmetric shapes. Negro scalp and facial hair fibers had twisted ribbon shapes which in cross-section appeared as flattened or curved ovals. Sharp twists along the fiber axis produced kinky hairs. Chinese scalp hairs were straight and regular, with circular or slightly oval cross- sections the beard hairs, however, showed the widest range of shapes. Measuring the cross-sectional areas and ellipticity via optical microscopy, the cross-sectional area of beard hair was found to be 70-1009'3 greater in all three racial groups than that of the corresponding scalp fibers (Table III). Beard fibers were more irregular in shape than the scalp fibers, giving larger ellipticity indices. Due to the variability among the hair fibers from each individual and among the individuals within each race, significant racial differences in the quantitation of size and shape of beard hair or scalp hair were not obtained from the limited data of this study. However, a trend emerged, showing that Chinese beard and scalp hairs were coarser and the cross-sections more circular than the corresponding fibers of Caucasian or Negro origins. Comparing the number of cuticle layers in beard and scalp hair samples, it was observed that there were nearly twice as many in facial hair as in the scalp fibers of the Table IV Number of Cuticle Layers in Beard and Scalp Hair a Fiber Type Beard Hair Scalp Hair Beard/Scalp Caucasian b 10.3 +_ 1.6 6.4 _+ 1.4 1.7 _+ 0.4 Black c 8.3 -+ 2.1 5.3 _+ 1.5 1.7 _+ 0.8 Chinese • 11.5 +_ 1.9 6.3 -+ 1.2 1.8 _+ 0.2 aDetermined from transmission electron micrographs. bFive fibers each from six subjects four cross-sections per fiber. CFive fibers each from four subjects four cross-sections per fiber. Average values and standard deviations are reported.