RHEOLOGICAL EVALUATION OF SEMISOLIDS 659 REFERENCES (1) Wood, J. H., Giles, W. H., anti Catacalos, ( ., Problems in cosmetic rheology, J. $oc. Cosmet. Chem., 15, 564-77 (1964). (2) Sherman, P., Techniques for assessing the rheological properties ooe toiletry and cosmetic products, Ibid., 17, 439-65 (1966). (3) Martin, A. N., Banker, ( . S., and Chun, A. H. C., Rheology, Advan. Pharm. Sci., 1, 1-8.5 (1964). (4) Lin, T J., Rheology Fundamentals and Applicalion•s in Cosmetic Industry, in aleNavarre, M. G., The Chemistry and Manufacture of Cosmetics, Vol. i, D. Van Nos(rand Co., Inc., Princeton, N.J., 1962, pp. 315-38. (5) Chong, C. W., Eriksen, S. P., and Swintosky, J. V., Antithixotropic behavior of magnesia magma, J. Amer. Pharm. Ass., Sci. Ed., 49, 547-52 (1960). (6) Aoki, M., Fukuchi, H., and Nakaya, S., Studies on pharmaceutical suspensions. (1) On the structural viscosity of oil suspensions, Chem. Pharm. Bull., 16, 171-6 (1968). (7) Reincr, M., and Scott Blair, G. W., Rheological Terminology, in Eirich, F. R., Rheology --Theory and Applications, Vol. 4, Academic Press, Inc., New York, 1967, pp. 461-88. (8) UmstStter, H., Kolloid-Z., 70, 174-80 (1935) through Houwink, R., Elasticity, Plasticity, and Structure of Matter, 2nd ed., Dover Publications, Inc., New York, 1958, pp. 12-4. (9) Boylan, J. C., Rheological evaluation of the spreading characteristics of pharmaceutical semisolids, J. Pharm. Sci., 56, 1164-9 (1967). (10) Davis, S.S., Shotton, E., and Warburton, B., Some limitations of continuous shear meth- ods for the study of pharmaceutical semi-solids, ]. Pharm. Pharmacol., Suppl., 20, 157S- 167S (1968). (11) Ferry, J. D., Rheology in the world of neglected dimensions, J. Chem. Educ., gS, 110-• (1961). (12) Barry, B. W., and Warburton, B., Some rheological aspects of cosmetics, .l. Soc. Co3met. Chem., 19, 725-44 (1968). (13) Van Wazer, J. R., Lyons, J. w., Kim, K. Y., and Colwell, R. E., Fiscosity and Flow Measurement--A Laboratory Handbook of Rheology, Interscience Publishers, New York, 1963, pp. 362-3. (14) Vand, V., Viscosity of solutions and suspensions. I. Theory, J. Phys. Colloid Chem., 52, 277-99 (1948). (15) Merrill, E. W., Non-Newtoniauism in Thin Liquids: Molecular and Physical Aapects, in Acrivos, A., Modern Chemical Engineering, Vol. 1, Reinhold Publishing Corp., New York, 1963, pp. 180-1. (16) Whirmore, R. L., The Viscous Flow of Disperse-Suspensions in Tubes, in Mill, C. C., Rheology of Disperse Systems, Pergamon Press, New York, 1959, pp. 49-60. (17) Bantort, E., Some Measurements on Pigment-Plasticizer Dispersions, in Mill, C. C., Rheology of Disperse Systems, Pergamon Press, New York, 1959, pp. 105-26. (18) Barry, B. W., and Shot(on, E., Performance of the Ferranti-Shirley viscometer with automatic flow curve recorder, .I. Pharm. Pharmacol., 21), 167-8 (1968). (19) Warburton, B., and Barry, B. •N., Concentric cylinder creep investigation of pharma- ceutical semi-solids, Ibid., 20, 255-68 (1968). (20) Davis, S.S., Viscoelastic properties of pharmaceutical semisolids. I: Ointment bases, .1. Pharm. Sci., 58, 412-8 (1969). (21) Davis, S.S., Viscoclastic properties of pharmaceutical semisolids. II: Creams, Ibid., 58, 418-42 (1969). (22) Kramer, A., Burkhardt, G. J., and Rogers, H. P., Jr., The shear-press: a device for measuring food quality, Canner, 112, No. 5, 34-6, 40 (1951). (23) Decker, R. W., Yeatman, J. N., Kramer, A., and Sidwell, A. P., Modifications of the shear-press for electrical indicating and recording, Food Technol., 11, 3t3-7 (1957).

660 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (24) Kramer, A., and Hawbecker, J. v., Measuring and recording theological properties of gels, Ibid., 20, 111-5 (1966). (25) Kramer, A., Texture, in Basic Principles of Sensory Evaluation, American Society for Testing and Materials, Philadelphia, 1968, pp. 49-50. (26) Charm, S. E., The determination of the tensile strength of fluid food materials, ]. Food Sci., 29, 483-6 (1964). (27) Pryce Jones, J., through Overbeck, J. Th. G., Rheology of Lyophobic Systems, in Kruyt, H. R., Colloid Science, Vol. 1, Elsevier Publishing Co., Inc., New York, 1952, p. 364. (28) Bruss, H., tCber die Bedeutung der Rheologie in der kosmetischen und pharmazeutischen Industrie, Parfuem. Kosmet., 41, 141-6 (1960). (29) Bruss, H., personal communication (August 17, 1965). (30) Treloar, L. R. G., The Physics o! Rubber Elasticity, Oxford University Press, London, 1949, p. 56. (31) Flory, P. J., Principles o[ Polymer Chemistry, Cornell University Press, Ithaca, N.Y., 1953, pp. 432-4 482-3. (32) Charm, S. E., The direct determination of shear stress-shear rate behavior of foods in the presence of a yield stress, J. Food Sci., 28, 107-13 (1963). (33) Casson, N., A Flow Equation [or Pigment-Oil Sitspensions o[ the Printing Ink Type, in Mill, C. C., Rheology o[ Disperse Systems, Pergamon Press, New York, 1959, pp. 84-104.