Book Reviews EMULSIONS: THEORY AND PRACTICE by Paul Becher, New York, Rein- hold Publishing Corporation. See- ond edition, 1965. 440 pages, il- lustrated and indexed. Price $22. Most cosmetic chemists who deal with emulsions must be familiar with the first edition of this book, which was published in 1957. This review may therefore concern itself principally with the amount of use- ful new material in the second edi- tion. First, let it be said that the ne•v edition, like the original, is a well organized, concise, and incisive treatise by a physical chemist who has made distinguished contributions to both theory and application in this field. The second edition is organized almost identically to the first, but Appendix B, which listed commercial emulsifying agents, has now been omitted because of the transient nature of such information. The new edition contains 93 more pages than did the old one minus Appendix B. Appendix A of the first edition, covering tests for emulsion properties, is now the last chapter of the text and is lengthened by ten pages- the references cited here have in- creased in number by 77%, the larg est increase in any chapter. Several new sections appear, including one on determination of HLB and of required HLB. Chapter 7 on techniques of emub siftcation has also grown notably in the elapsed eight years. Its section on mixing time and general technique contains much new mate- rial, and the following sections have been added: Emulsion type Orifice mixing High shear Ultrasonic methods Spontaneous emulsification Microemulsions Homogeneous emulsions. Several new pieces of emulsifying equipment are pictured. In Chapter 4 on theory of emul- sions:stability, considerable new ma- terial is found, including: a new section on viscosity of the interfacial film, and one on spreading coefficient and sta- bility 537

538 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS a new section on electrophoresis and zeta potential extensive reorganization of the material on double layer and potentials. Chapter 2 contains more material than before on micelies, and Chapter 5 presents several new figures on emulsion inversion, new sections on the mechanisms of coalescence and of rupture, and several new sections on other phenomena of emulsifica- tion. Chapter 6 includes the phosphate esters, fluorinated nonionics, and silicone nonionics in its treatment of emulsifying agents. It also con- tains a new l 1-page section on the theoretical significance of HLB. The particle-size material of Chapter 3 is reorganized, and more material on viscosity has been added to this chapter on physical properties of emulsions. Elsewhere, the newer data and concepts have been fitted into the framework set up for the first edition. The importance of the new material fully justifies the new edition, which cites 40% more literature references than the old and thus provides full and up to data coverage of material highly useful to the cosmetic chemist. Under "Terminology" on page 2 we still find the arresting statement: "The disperse phase may also be referred to as the nondisperse or discontinuous phase." On the whole, however, errors are very few, and the paper and typography combine with the clarity of style to make the book easy to read.--PAuL G. I. LAurrER--Chesebrough-Pond's, Inc. THE STRUCTURE AND PROPERTIES OF BIOLOGICAL SYSTEMS, ADVANCES IN CttEMICAL PitYSiCS, Volume VII, edited by J. Duchesne, Interscience Publishers, New York. 1964. 754 pages, illustrated and indexed. Price $27.50. With this volume, this series ven- tures into the field of biology for the first time. It treats the field from the viewpoint of modern physics. A wide international array of authors have submitted chapters, and where necessary excellent English trans- lations have been provided. The book is divided into a theoretical part and an experimental part, the over-all goal being to utilize quantum mechanics to try to establish quan- titative relationships between bio- logical activity and certain electronic and energetic molecular indices of biological molecules. The theoretical chapters 1 to 4 deal with the properties of DNA, RNA hemoproteins and coenzymes. The other 14 chapters deal with a variety of experimental approaches to at- tempt to understand various bio- logical molecules or systems. For example, the effects of ionizing radia- tions, hydration, and thermal re- sponses are used to elucidate molec- ular structure. Model systems are subjected to careful measurements of their electrical and magnetic prop- erties to explain the properties of more complicated biological com- pounds. The possibilities of modern spectroscopic methods are examined in dealing with complex biological systems in their natural aqueous environments. The detailed ex-