J soc. COS. CHEM. 15,519-522 (1964) BOOK REVIEWS AN INTROI•VCTION TO CLAY COL- LOrn C•EmSTP.¾ •'Oe. CLAY TEC•- NOLOGISTS, GEOLOGISTS, AND SOIL SCI•.NTISTS, by H. van Olphen. John Wiley & Sons, Interscience Division, New York, N.Y. 1963. 301 pages, illustrated and indexed. Price $10. Despite the fact that the title of this book appears to limit its readers to only a few groups, the cosmetic chemist will do well to add it to his library. Anyone who has attempted to cope with the literature dealing with colloidal states or suspension sys- tems soon becomes aware of the state of confusion which exists in the terms, definitions, and explana- tion of concepts and theories in this area. The author recognizes the misleading aspects of this situation and makes a positive effort to describe the proper usage of each term at the time he introduces it in his book. The first five chapters are devoted to lucid explanations of concepts concerning colloidal systems in gen- eral and clay suspensions as related to the properties and stability of hydrophobic sols. Dr. van Olphen leads his readers through excellent discussions of the theories of set- tling? aging, and flocculation of sus- pensions. He deals with the origin of electric charges on particles which contribute to the stability of the system or detract from it. The theories which exist on the stability of hydrophobic sols are presented and discussed, including a summation of the forces of repulsion and attraction which af- fect stability. Although the bal- ance of the book deals almost ex- clusively with clay mineralogy and clay suspensions, the sections dealing with theories of stability and those concerned with technological ap- plication of stability control should prove valuable to the research chemist who must cope with the manifold problems in the develop- ment of a stable suspension of any sort. A valuable feature of the book is the inclusion of several appendixes which p.resent information on the preparation of clay suspensions, electric double-layer computations, van der Waals attraction energy between two unit layers, and refer- ences to books, monographs and periodic publications on clay litera- ture. The illustrations nicely augment the text and help in clarifying most of the basic principles involved. The only major criticism in this respect is that more of such illustra- tions could have been employed throughout the book. The index is good, and the text is free of typo- graphical errors.--Jos•PH L. K^NIG, Columbia University, College of Pharmacy. ELASTOL¾SIS AND AGING, by David A. Hall. Charles C Thomas, Spring- field, Ill. 1964. xiii -3- 160 pages, illustrated and indexed. Price $6.75. The aging of elastic tissues is a subject of prime interest to the cosmetic chemist. This is a highly 519

5:20 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS specialized book, as indicated by the author in the foreword: "Full coverage of the whole question of elastase action has recently appeared in two ad- mirable reviews by Mandl (ddv. Enzymol., 23, 163-264 (1961)) and Loeven ("The Enzymes of the Elastase Complex," in In- ternat. Reviews Connective Research 1, 1963, D. A. Hall, ed., Academic Press, N.Y.). By their very na- ture, however, these reviews were truly impartial and it is my hope that the admittedly more partisan approach which I have made in the present monograph will, if only by posing controversial hy- potheses, act as a starting point for further discussion." It is thus evident that the com- plex problem of the composition of elastase and of its role in aging phenomena in connective tissue is assessed differently by various work- ers. The book here reviewed de- votes only 18 pages to dicsussion of elastolysis and the aging process. The remainder of the text concerns itself with the nature of elastic tis- sue, the elastolytic enzymes, and the inhibitors of such enzymes. Most studies of elastolysis have been carried out on the elastic tis- sue of the intima, or innermost layer, of arteries. As noted by the author (p. 43), the tissue com- ponent called elastin, on the basis of its histological appearance, may have a highly varied composition. Most studies on the composition of elastin have been made on material derived from the nuchal ligaments of beef cattle. It is questionable how much of the data reported for arterial intima and for nuchal liga- ments could be utilized in studies of the elastic tissue of the skin. An understanding of the changes occurring in aging skin would, of course, be of immense value to the cosmetic chemist. The work under review makes it painfully clear that such understanding is likely to come only after the cosmetic industry has undertaken its own investigation of the aging process in skin. Hall's book would be of great value in preparing for such work. Most cosmetic chemists would probably obtain a broader back- ground by reading first the 1963 book edited by Hall (cited above), which examines all components of connective tissue. The 1964 book, here under review, would then round out the picture of the tissue that underlies so many of our efforts.-- PAVL G.I. LAVFF•.R, Cheesebrough- Pond's Inc. VISCOSITY AND FLOW MEASURE- MENT--A LABORATORY HANDBOOK OF RHEOLOGY by J. R. van Wazer, J. W. Lyons, K. V. Kim, and R. E. Colwell. Interscience Publishers, Inc., New York, N. Y. 1963. 406 pages. Price $14.00 The apparent purpose of this book was to present rheological theory, not comprehensively but as a background for a better under- standing of basic principles involved in laboratory rheology instrumen- tation and practice. To this ex- tent, the book is more than moder- ately successful. The first chapter, entitled "Fundamentals of Rheol- ogy," deals with basic theory of elasticity, viscosity and the mathe- matical theory of flow. The dis- cussion of elasticity is a. noteworthy achievement of conciseness and clarity. The concepts of viscosity are explained in a somewhat less complete manner but are still lucid and thorough. The mathematical theory of flow, which follows, is too brief, probably in an attempt to avoid lengthy derivations. As a result, it serves more as a distrac- tion than an aid to understanding.