BOOK REVIEWS SURFACE ACTIVE AGENTS AND DETERGENTS, Volume !I, by An- thony M. Schwartz, James W. Perry and Julian Berch. Inter- science Publishers, Inc., New York 1, N.Y. 1957. 860 pages, illus- trated and indexed. Price $17.50. An earlier volume published in 1949 is Volume I of this set. The present volume brings up to date material appearing since publi- cation of the earlier volume. The work is divided into four parts, the processes of synthesizing and manufacturing surfactants, special function of surfactants and com- positions, physical and colloidal chemistry of surfactants and practical applications of surfactants. New trade names are used wher- ever possible. Patents, literature and manufacturers data are care- fully footnoted on each page. Ampholytes, the most recent surfactants to gain usage are de- scribed in a number of places, but mainly on pages 171, 138-143 and 227. A portion of the section on applications covers cosmetics in some ten pages or so. However, the inactivation of germicides by nonionics does not appear to be included. The book is well made. No errors were noticed during ex- amination of many of the pages. This companion volume cannot be recommended too highly to set beside its earlier Volume I.--M. G. DENAVARRE. MOLECULAR STRUCTURE AND ORGANOLEPTIC QUALITY, comprising papers read at a symposium organ- ized by the Overseas Section, Soci- ety of Chemical Industry, Geneva, Switzerland, May 2-3, 1957. S.C. !. Monograph No. 1. The Mac- millan Co., New York. 1957. 124 pages. Price $3.75. In May, 1957, several of the world's outstanding scientists in the field of odor chemistry read papers at a symposium of the Society of Chemical Industry in Geneva, Switzerland. These papers, and the brief but significant discussion, are gathered and published in book form as S. C. I. Monograph No. 1. The literature of oilaction has been marked by unproven asser- tions, contradictions and conjectures constituting an obstacle facing workers seeking to construct scien- tifically valid concepts. The in- ability to classify odors, the con- tradictions between the reports of diverse investigators, the reactions of single individuals reported as if they were reproducible, the lack of an accepted theory of the mechanism by which the animal (human and infrahuman) smells. These are factors militating against progress in an understanding of odor. Despite the caliber of the contributors to this symposium (Ruzicka, Stoll, Beets, Naves, among others), the difficulties of contradiction and con- jecture are seldom avoided and occasionally aggravated in these 126

BOOK REVIEWS 127 papers. In fact, Ruzicka (his summary essay is typically brilliant) takes note of the diversity of view- points among the writers. The book consists of eight brief pape.rs, with Stoll delivering an opening discourse on molecular structure and odor. How tortuous are the theories necessary to fit odor and structure into a pattern, and how numerous are the exceptions necessary to permit such theories to stand. Kalmus, m the second paper., deals with physiology and genetics Stiras and Demeillers write on the measurement of odor intensity Naves followed by Beets (these chapters are, to this reader, the highlights of the book) on stereochemistry and odor, and on structure and odor, respectively Wright puts forth his theory of molecular vibration, and is followed by Thompson, who refutes it and Ruzicka summarizes. That there should be clashes of opinion in a work of this sort is expected, and the Wright-Thompson debate, in that respect, is of great interest. But that there should be conflict of factual testimony is disconcerting, for it indicates that even amongst the best chemists, the reporting of work in odor continues to suffer from severe limitations. Two instances of such conflict between Stoll and Naves will be cited. Stoll: "No odorous sub- stance is known with a molecular weight above $00." Naves: "We know that organic substances with a molecular weight of 600 to 800 or more are odorous." Again, Stoll: "When isomerism is produced by an asymmetric carbon atom, i.e., as in optica! isomers, the odor of the isomers •s generally the same." Naves: "Enantiomers have dif- ferent odors and (that) the odor of the racetalc substance is different again." Two ambiguities that may lead to serious misunderstanding should be cleared up. They are from the same contributors, Stoll and Naves. The former states: "Colorists have much more difficulty in identifying a molecular structure by means of color than perfumer-chemists have when smelling an odor." If by "identifying" one means the recog- nition of a known substance, this is true if it means the elucidation of the structure of that substance, it is obviously not so. From Naves: "Whilst a substance ap- pears to be pure whatever the physical or chemical tests to which •t •s submitted, it can exhibit olfactory characteristics according to its origin." Here, the author would surely emphasize "appears to be" as the key words, admitting that there must be trace substances contributing to the odor, but not identifiable by physical and chem- ical tests. What is admirable about the work of Naves is not only the documentary evidence submitted for all assertions, but his critical evaluation of previous workers. He recognizes the difficulties that have beset odor chemists in the past because of false contentions, and with characteristic courage he names those whose work he rejects and cites reasons for such rejection. Of the stimulating debate be- tween Wright and Thompson, one is impressed, as is so often the case in olfactory theories, with the difficulties of proving one's asser- tions, and the ease with which they are disproved. Stiras and Demeillers describe an apparatus for the determination of odor intensity. The apparatus is based on a system of air dilution. Some of their reports, in this re- viewer's opinion, should have been excluded, because they are studies