70 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS of the cells, thus phosphorylase and amylo 1,4-1,6 transglucosidase are probably important in epidermal cell renewal, in protoplasmic differentia- tion and in the process of keratinization. One epidermal enzyme that has been investigated does not show marked regional variation. The enzyme that I refer to is fi-glucuronidase and it shows extremely little variability over the surface of the body. Most regions have only scant amounts of the enzyme in the Malpighian layer (16) but even in the case of this enzyme subtle regional differences can be demonstrated by both the visual and the photometric assessment of the end product of the histochemical reaction. The skin from the umbilical region has a slightly higher level of enzymatic activity than most of the other regions on the body and the epidermis of the axilla gives a very intense reaction for fi-glucuronidase (20). So even in the case of this enzyme, distinct regional differences exist, but they are less sweeping than those of other enzym es already mentioned. Thus, there is now definite evidence that a variety of enzymes serving. different functions show distinct and measurable differences in the epidermis over the body surface. Some of these enzymes are involved in the re- duplication of epidermal cells and may limil or accelerate cellular prolifera- tion. Other enzymes, such as acid phosphatase, esterases, phosphorylase, and fi-glucuronidase, are more abundant in the upper level of the Mal- pighian layer and these enzymes are probably functioning in protoplasmic differentiation of the cells and in the process of keratinization. Probably some of the enzymes that have been mentioned are engaged in both cellular proliferation and protoplasmic differentiation. The enzymes on which some data is now available, are but a few of the multitude of enzymes that are functional within the epidermal cells. It is not difficult to conceive of a vast spectrum of enzymes, which is continually changing in its activities throughout the entire epidermis. Subtle changes in diverse enzyme systems might produce the variability that we see in the morphology and physiology of the epidermis from one region to another. The regulation and control of these enzymes would be directly related to the genes. In a system such as the epidermis, where altering the genetic material is impossible, the next logical point for artificial control of the epidermal activity is at the enzymatic level. Most enzymes are stimulated or in- hibited by specific organic molecules or inorganic ions. It is not unreason- able to assume that the activity of the epidermal enzymes could be modified in situ just as it can be regulated in the test tube. Before such manipula- tions can become fruitful, however, our scant knowledge of the functions of the epidermal enzymes must be greatly extended. Such studies will not only be invaluable to the cosmetic chemist, but may also provide the biologist with the answer to the basic problem of how the genetic material regulates cellular differentiation.

PATTERNS OF REACTION OF THE SKIN TO INJURY 71 (26) (27) REFEKENCES (1) Argyris, T. S., ?[nat. Record, 125, 105 (1956). (2) Bejdl, W., Z. Zellforsch. u. mikroskop. ?[nat., 40, 389 (1954). (3) Braun-Falco, O., bfaut ?[rch. klin. exptl. Dermatol., 202, 153 (1955). (4) Bullough, W. S., Biol. Rev., 27, 133 (1952). (5) Bullough, W. S., and Lawrence, E. B., "The Mitotic Activity of the Follicle," in "The Biology of Hair Growth," W. Montagna and R. A. Ellis, Editors, New York, Academic Press, Inc. (1958), pp. 171-172. (6) Edwards, E. A., and Duntley, S. Q., ?ira. y. ?[nat., 65, 1 (1939). (7) Ellis, R. A., Ageing of the Human Male Scalp, in "The Biology of Hair Growth," W. Montagna and R. A. Ellis, editors, New York, Academic Press, Inc. (1958), pp. 469- 485. (8) Ellis, R. A., and Montagna, W., y. Histochem. and Cytochem., 6, 201 (1958). (9) Herrmann, F., Harbev, L. C., Scher, R., and Mondol, L., ?[.M.?[. ?[rch. Dermatol., 76, 282 (1957). (10) Hershey, F. B., Lewis, C., Murphy, J., and Schiff, T., y. Histochem. and Cytochem., 8, 41 (1960). (11) Horstmann, E., Die Haut, in "Handbuch der mikroskopischen Anatomie des Menschen," W. v. Mollendorff, Ed., $ (1), (1957), pp. 1-276. (12) Katzberg, A., ?[nat. Record, 112, 418 (1952). (13) Kopf, Alfred W., ?[.M.?[. ?[rch. DermatoL, 75, 1 (1957). (14) Loeb, L. and Haven, P. L., ?[nat. Record, 42, 217 (1929). (15) Montagna, W., 5 t. Biophys. and Blochem. CytoL, 1, 13 (1955). (16) Montagna, W., ]bid., $, 343 (1957). (17) Montagna, W., and Ellis, R. A., y. Natl. CancerInst., 19, 451 (1957). (18) Montagna, W., and Formisano, V., ?[nat. Record, 122, 65 (1955). (19) Moretti, G., Adachi, K., and Ellis, R. A., y. Histochem. and Cytochem., 8, 237 (1960). (20) Moretti, G., Adachi, K., Mescon, H., and Pochi, P., in press (1961). (21) Moretti, G., Ellis, R. A., and Mescon, H., y. Invest. Dermatol., 33, 103 (1959). (22) Rawles, M. E., The Skin and Its Derivatives, in "Analysis of Development," Willier, Weiss and Hamburger, editors, Philadelphia, W. B. Saunders Co. (1955), pp. 499-519. (23) Rothman, S., "The Physiology and Biochemistry of Skin," Chicago, Univ. of Chicago Press (1954). (24) Schering, L. E., ?[nat. Record, 135, 7 (1959). (25) Straus, W. L., Jr., The Microscopic Anatomy of the Skin of the Gorilla, in "The Anatomy of the Gorilla," W. K. Gregory, ed., New York, Columbia Univ. Press (1950), pp. 213- 226. Thuringer, J. M,., and Katzberg, A. A., y. Invest. Dermatol., 33, 35 (1959). Montagna, W., 'The Structure and Function of Skin," New York, Academic Press, Inc. (1956). PATTERN S O F REACTION O F THE SKIN TO INJURY By ALL^N L. Lo}ttNcz, M.D.* Presented September 1546, 1960, Seminar, Chicago A•ao• T•E PA??ER•S of reaction of the skin to injury two general ones which may be elicited by a wide variety of factors are encountered so frequently as to deserve special consideration as rather fundamental ele- ments in cutaneous pathology. These reaction patterns are namely ec- zematous and urticarial. The eczematous reaction pattern has greater significance for the cosmetic chemist because it is so very often triggered by substances coming into contact with the skin. * Assdciate Professor of Dermatology, The University of Chicago, Chicago, Ill.