306 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS sensitivity, et cetera. Under intense filtered ultraviolet illumination, fluorescent areas could be clearly focused upon the ground glass of the camera but curiously did not appear in the processed panchromatic nega- tives. However, it was discovered that when a pale yellow filter was used on the lens during exposure, the fluorescent sites were recorded in excellent detail and were greatly dependent upon the density of the particular filter used. The accompanying figures are presented as general examples of sebum fluorescence and glandular excretion. All were photographed by Lewis J. Sunny, B.P.A., using filtered ultraviolet light as the sole source of illumination. BIBLIOGRAPHY (1) Rothman, Stephan, "Physiology and Biochemistry of the Skin," Chicago, The University of Chicago Press (1954), pp. 284-336. (2) Montagna, W., "The Structure and Function of Skin," New York, Academic Press, Inc. (1956), pp. 255-293. (3) Weitkamp, A. W., •. •lm. Chem. Soc., 67, 447 (1945). (4) MacKenna, R. M. B., Wheatley, V. R., and Wormall• A., 7. Invest. Dermatol., 15, 33 (1950). (5) Wheatley, V. R., St. Bartholomew's bjrosp. 7, 57, 5 (1953). (6) Rothman, S., and Schaaf, F., in Jadassohn, "Handb. d. Haut- u. Geschlechtskr.," Vol. 1, Berlin, J. Springer (1929), p. 161. (7) Peck, S. M., Rosenfeld, H., Leifer, W., and Bierman, W., dcrh. Dermatol. and Syphilol., 39, 126 (1939). (8) Burtenshaw, J. M. L., 7. Hyg., 42, 184 (1942). RHEOLOGICAL REVIEW FOR COSMETIC CHEMISTS* By A. L. SeARBROUGH National Lead Company, New York, N.Y. RHF. OLO•V is the science of the deformation and flow of matter. That is a rather sweeping definition, since it allows ample room for studies from mayonnaise to volcanic lava, as well as from blood serum to wet sea sand. Our purpose here, since the scope of the subject is enormous, is to choose a few aspects which might have a direct and practical bearing in the field of cosmetic chemistry. We should like to suggest a few thoughts which may be helpful in your work of continual improvement of various pastes, creams, solutions and emulsions, the bulwark of your trade. Perhaps it would also be well to enter a standard disclaimer clause at this point. We are all familiar with the necessary custom in the chemical in- dustry. The printed brochure describes wonderful new products and rec- * Presented at the October 24, 1956, Meeting, New York Chapter, New York City,

306 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS sensitivity, et cetera. Under intense filtered ultraviolet illumination, fluorescent areas could be clearly focused upon the ground glass of the camera but curiously did not appear in the processed panchromatic nega- tives. However, it was discovered that when a pale yellow filter was used on the lens during exposure, the fluorescent sites were recorded in excellent detail and were greatly dependent upon the density of the particular filter used. The accompanying figures are presented as general examples of sebum fluorescence and glandular excretion. All were photographed by Lewis J. Sunny, B.P.A., using filtered ultraviolet light as the sole source of illumination. BIBLIOGRAPHY (1) Rothman, Stephan, "Physiology and Biochemistry of the Skin," Chicago, The University of Chicago Press (1954), pp. 284-336. (2) Montagna, W., "The Structure and Function of Skin," New York, Academic Press, Inc. (1956), pp. 255-293. (3) Weitkamp, A. W., •. •lm. Chem. Soc., 67, 447 (1945). (4) MacKenna, R. M. B., Wheatley, V. R., and Wormall• A., 7. Invest. Dermatol., 15, 33 (1950). (5) Wheatley, V. R., St. Bartholomew's bjrosp. 7, 57, 5 (1953). (6) Rothman, S., and Schaaf, F., in Jadassohn, "Handb. d. Haut- u. Geschlechtskr.," Vol. 1, Berlin, J. Springer (1929), p. 161. (7) Peck, S. M., Rosenfeld, H., Leifer, W., and Bierman, W., dcrh. Dermatol. and Syphilol., 39, 126 (1939). (8) Burtenshaw, J. M. L., 7. Hyg., 42, 184 (1942). RHEOLOGICAL REVIEW FOR COSMETIC CHEMISTS* By A. L. SeARBROUGH National Lead Company, New York, N.Y. RHF. OLO•V is the science of the deformation and flow of matter. That is a rather sweeping definition, since it allows ample room for studies from mayonnaise to volcanic lava, as well as from blood serum to wet sea sand. Our purpose here, since the scope of the subject is enormous, is to choose a few aspects which might have a direct and practical bearing in the field of cosmetic chemistry. We should like to suggest a few thoughts which may be helpful in your work of continual improvement of various pastes, creams, solutions and emulsions, the bulwark of your trade. Perhaps it would also be well to enter a standard disclaimer clause at this point. We are all familiar with the necessary custom in the chemical in- dustry. The printed brochure describes wonderful new products and rec- * Presented at the October 24, 1956, Meeting, New York Chapter, New York City,