832 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS peared in various scientific journals repetition now can be justified only by the attempt to publish the complete proceedings of the symposium. Aging of the skin and of its ap- pendages is an important social prob- lem for older members of a youth- oriented society. It is surprising, therefore, that this book includes only one chapter on attempts to improve or rejuvenate aging skin by clinical methods. On the other hand, about 15 of the 17 chapters of this book deal with comparisons between young and old skin. Unfortunately, the reader is not alerted to the fact that horizon- tal aging studies--and this book is concerned only with comparisons be- tween skin of different individuals of different ages--are not as definitive as longitudinal studies. The reader of a scientific book is en- titled to expect the author to delineate new problems, point out unusual findings, and if possible give some scientifically sound explanation. Thus, it is disturbing that one author neglected to mention that amino add analyses of derreal tissue suggest that the total collagen content of elastotic skin is closer to that of skin from pre- mature infants than that of normal (?) adults. This reviewer is not qualified to judge the histological and morpholog- ical observations of aging skin which account for several major chapters in the book. On the other hand, some of the gross observations of the gray- ing of hair appear to be not quite justified. One of the authors states that "graying appears first on the temples .... In a recent exmnina- tion of eight octogenarians, virtually no hypomelanotic hairs were found in the axillae, presternum and pubis." From personal observation, this re- viexver knows that graying in males frequently occurs first in the prester- hum area. In the same section it is noted that "before the hair becomes completely white, the pigmentation of the individual hairs that together with others look gray, may cover the entire range of color dilution.' This statement implies that fibers grad- ually change color until they finally turn completely white and is, there- fore, contrary to observed facts. Despite the above-voiced objec- tions to the book, this volume is im- portant reading for those of us who are interested in the aging of skin and related phenomena. The book pre- sents some significant new data, on one hand, and, at times, is an excel- lent and comprehensive review. The reader is, however, advised to analyze and examine observations and state- ments with considerable care before accepting all the conclusions made by the contributors.--M. M. RIEGER-- Warner-Lambert Research Institute. ENCYCLOPEDIA OF CHEMISTRY, 2nd Edition, edited by G. L. Clark and G. G. Hawley. Reinhold Publishing Corp., New York, N.Y. 1966. 1114 pages, illustrated and indexed. Price $25. The reviewing of an encyclopedia is not an easy task: Sometimes the value of an encyclopedia lies in the number of entries, and sometimes it is to be found in the colnpleteness of

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 833 coverage of the subject. Neither of these criteria can be applied to this particular volume. Instead, the orig- inal meaning of the Greek word, en- cyclopedia, i.e., instruction in a broad area of knowledge, describes this vol- ume more precisely. In fact, this en- cyclopedia is an alphabetically ar- ranged textbook of chemistry and chemical technology. The number of entries is limited, but each of them is detailed enough to provide broad coverage of the subject under scru- tiny. This book is not for the novice but requires some background in chemistry. Each entry is carefully explained, and some derivation of equations is given it serves as an in- troduction to the subject and at the same time is an excellent review for those who are already familiar with it. What is particularly noteworthy is the fact that each entry is truly a brief and readable discussion of an im- portant subject. Typical is the three-page entry on foam. There are no separate entries for the Gibbs ad- sorption theorem, the Laplace and Marangoni effects, and antifoams instead, these points are presented in a logical manner and in a clear and concise style, which makes for pleas- urable reading. This reviewer was impressed by the large list of contributors, many of whom are well-known experts in their respective fields. Although it may be presumptious to recommend reading of an encyclopedia from cover to cover, such an activity would be an excellent refresher course in chemis- try. Even occasional browsing through this volume will be reward- ing and finally, this book will serve well as a desk reference. The empha- sis of this encyclopedia is not on de- tails (which can be found readily in the various handbooks of chemistry) but on the broad principles and theo- retical aspects. Therein lies the main value of this book, which can be rec- ommended to all unequivocally.-- M. M. RIEoER--Warner-Lambert Research Institute.