52 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS of fatigue in combination with some preexisting damage. Treatment of the fibers with alkali or thioglycolic acid reduces the number of fibrillated ends, especially at high fatigue loads, and increases the number of smooth fractures. Premature failures result from preexisting damage in the fiber. Moisture content plays an important role in controlling the number of premature failures, suggesting that stress relaxation at crack tips may be involved. Treatment with humectants such as polyacrylic acid and glycerin have been found to be beneficial, PAA appearing to be more effective. There is some evidence that increase in moisture content may be re- sponsible for the reduction in premature failures in humectant-treated hair. Breaking extension data on humectant-treated fibers suggest that in PAA-treated fibers a larger amount of moisture is likely to be present near the periphery of the fiber where cracks exist. Thioglycolic acid pretreatments seem to enhance preexisting damage in the fibers, thus eliminating the beneficial effects of humectants. ACKNOWLEDGEMENT These studies formed one aspect of the work on the Textile Research Institute project "Properties of Negroid Hair," supported by Nicholas Laboratories, Inc. REFERENCES (1) J. Epps and L. J. Wolfram, Letter co the ediror, J. Soc. Cosmet. Chem., 34, 213 (1983). (2) Y. K. Kamarh, S. B. Hornby, and H.-D. Weigmann, Mechanical and fracrographic behavior of negroid hair, J. Soc. Cosmet. Chem., 35, 21-43 (1984). (3) J. Menkarr, L.J. Wolfram, and I. Mao, Caucasian hair, Negro hair and wool. Similarities and differences. J. Soc. Cosmet. Chem., 17, 769 (1966). (4) Y. K. Kamarh and H.-D. Weigmann, Fracrography of human hair, J. Appl. Po/ym. ScJ., 27, 3809- 3833 (1982). (5) J. Chao, E. Newsom, I. M. Wainwright, and R. A. Mathews, Comparison of the effects of some reactive chemicals on the proteins of whole hair, cuticle and cortex, J. So . Cosmet. Chem., 30, 401- 413 (1979).

j. Soc. Cosmet. Chem., 36, 53-59 (January/February 1985) Electron microscopy-image analysis: Quantification of ultrastructural changes in hair fiber cross sections as a result of cosmetic treatment JACALYN G. GOULD and RAYMOND L. SNEATH, The Gillette Company, Personal Care Division, Gillette Park, Boston, Massachusetts 02106. Received October 31, 1984. Presented at the Society of Cosmetic Chemists Annual Meeting, New York, December 6-7, 1984. Synopsis In a recent publication, Kaplin et al. described the dissolution of ultrastructural components in hair fibers as a direct result of various cosmetic treatments. These observations were based on a subjective assessment of holes or voids observed in electron micrographs of hair fiber cross sections. We have further investigated these effects using electron microscopy in conjunction with image analysis. Cross sections of proximal and distal ends of intact hair fibers were examined before and after repeated shampooings. The total number of holes, total projected areas, mean areas, and size distributions were determined in the cuticle and cortex regions of hair fibers using a Quantimet 900 Image Analyzer. All measured parameters indicated that ultrastructural disruption increased from the proximal to the distal end of hair fibers. The-impact of shampooing was limited to the cuticle region of weathered hair fibers. INTRODUCTION The ultrastructural organziation of the hair fiber has been extensively studied over the past decade. The keratin components of the hair, which constitute about 85%'of the mass of the fiber, are considered to make the major contribution to the chemical and physical properties of the hair. The remainder of the fiber consists of non-keratinous materials in the form of intercellular membranes and the remnants of cellular constit- uents. These non-keratinous materials have recently been the subject of investigations concerning their contribution to the integrity of the fully keratinized hair fiber. Figure 1 provides a schematic diagram of the non-keratinous regions of the hair fiber in transverse section. The detailed structure and chemical composition of these regions have been revealed by electron microscopy used in combination with various chemical studies. The intercellular membranes form a network structure between both cuticle and cortical cells. Electron micrographs show that these membranes consist of two lipid layers, the [3-1ayers, and a central non-keratinous protein layer, the 8-layer, often referred to as the intercellular cement (1-3). The cell membranes and the intercellular cement make up the so-called cell membrane complex of keratin fibers. Although resistant to attack 53