194 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 15. Small, apparently intracellular, laminar structures that contain lanolin/marker in their outer layers. intercellular lipid bilayers, at least (apparently) in trilaminar structures forming the outer envelope of corneocytes. This work suggests that lanolin achieves its moisturizing action by absorption deep into the stratum corneum. Once there, whether its action is partial occlusion of natural water pathways, or due to being taken up into natural lipid bilayers, or due to providing an additional water reservoir, is not yet entirely clear. There is, however, some evidence suggesting that lanolin may penetrate corneocytes and become incorporated into laminar structures such as cell envelope material. Evidence suggesting the spontaneous emulsi- fication of epidermal water by intercellular lanolin has been seen. ACKNOWLEDGMENT The assistance of Dr. Ashley J. Wilson of CCTR, University of York, Heslington, England, in interpreting the photomicrographs is gratefully acknowledged. REFERENCES (1) E. W. Clark, A brief history of lanolin, Pharm. Historian, 10, 5-6 (1980). (2) E. W. Clark, New concepts of lanolin. Presentation at In-Cosmetics Seminar, NEC, Birmingham, England, March, 1990. (3) D. H. Powers and C. Fox, A study of the effect of cosmetic ingredients, creams and lotions on the rate of moisture loss from the skin, Proc. $ci. Sec. Toilet Goods Assoc., 28, 21-26 (1957).

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