BOOK REVIEWS 761 strands of nucleic acids. On the basis of the results obtained a tentative explanation is presented of the specificity of the genetic code. "Ionic radii and enthalpies of hydration of ions" (D. F. C. Morris) discusses the relationship between ionic crystal radii and absolute heats of hydration. "Crystal chemistry of chalcogenides and pnictides of the transition elements" (F. Hulliger) reviews very thoroughly the structures and properties of crystals of compounds of the transition elements with the chalcogenides O, S, Se, and Te, and with the pnictides, P, As, Sb, and Bi. The volumes are produced to a high standard and have semi-stiff covers. They arc not indexed, but in books concerned primarily with theroetical discussions this is perhaps not a serious omission. B.G. OVERELL. ESSAYS IN BIOCHEMISTRY. Vol. 3. Editors: P. N. Campbell and G. D. Greville. Pp. xi q- 168 + Ill. (1967). Academic Press, London/New York. 22/6. $3.50. The publication of this series of essays has now, in its third year, become a permanent feature of the Biochemical Society's activities, The essays are designed for students and for scientists wishing to keep up to date in topics outside their oxvn specialities. In this volume of four essays, three deal with various aspects of the structure and function of proteins, and one with an aspect of hormone action. "The structure of immunoglobulins" (Rodney R. Porter) describes work carried out on the proteins which can carry antibody activity. These proteins have mole- cular weights in the region of 150,000, and exist in mammalian sera as three main classes of molecules, each class comprising a collection of heterogeneous molecules differing slightly in amino acid sequence. Work in this field would probably have made relatively little progress but for two findings: that the abnormal serum proteins found in patients with myelomatosis are homogeneous immunoglobulins, and that the molecules can be split to give subunits of 20-25,000 molecular weight. The arrange- ment of the various polypeptide chains in the molecule have been known for some years, and large sections of the amino acid sequences are now known. Indications as to the relationship of the amino acid sequence to the specificity of antibodies should become apparent quite soon. "The foundations of enzyme action" (H. Gutfreund and J. R. Knowles) discusses the general features of enzyme catalysis which are now evident, although no enzyme has yet been studied in sufficiently complete detail for an exact reaction mechanism to be presented. The enzyme molecule as a whole is considered to be essential for its activity, in the absence of convincing evidence to the contrary, and therefore consideration of the configuration of the molecule as well as its primary structure is essential. Reaction mechanisms are discussed by which functional groups in enzyme molecules could effect reduction of activation energies of enzyme pro- cesses below that of the uncatalysed reactions. "Structural and function of glycoproteins" (P. W. Kent) is concerned with those carbohydrate-containing proteins which are not classified as mucopolysaccharides. The latter contain uronic acids or sulphate esters, and carbohydrate is bound to the

762 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS protein by ionic linkages as well as by covalent bonds. The glycoproteins contain no uronic acids, few contain sulphate esters, and the linkages are covalent. Three main advances have contributed to rapid progress in this field: the establishment of structure of the sialic acids, which are almost universal constituents of glycoproteins the elucidation of the types of bond between carbohydrate and protein, the [[-aspart- amidoglycosyl and the serine and threonine O-glycoside links and the development of analytical techniques such as sequential periodate oxidation and borohydride re- duction to provide information about the nature of the glycosidic bond. Glyco~ proteins dealt with in detail include those from submaxillary gland, serum glyco- proteins, the blood group substances, and the glycoproteins from intestine, urine, connective tissue, and bone. The viscous glycoproteins, such as mucins, have a large number of carbohydrate side branches terminating in sialic acid or fucose, whereas globular glycoproteins such as fetuin have relatively few, but large, carbohydrate structures attached to protein chains. Little is yet known about the tertiary structure of these molecules. "Some actions of hormones in the regulation of glucose metabolism" (C. N. Hales) takes as its central theme the role of insulin in mediating responses to the availability of dietary glucose. Insulin increases glucose transport in muscle and adipose tissues, but this does not explain all its effects. The interaction of glucagon, gro•vth hormone, cortisol and adrenaline are discussed. An interesting feature is the interpolation of several reactions between the initial effect of a hormone and the modification of a metabolic pathxvay: such a "cascade" may provide a biological amplification system. A large amount of evidence now indicates that the effect of many hormones is exerted on cell membranes, and future progress in understanding mechanisms of hormone action will depend on advances in the study of cell membranes. This volume continues the high standard of its predecessors and forms a useful addition to the series. B.G. OVERELI,. AN INTRODUCTION TO THE LIOUID STATE. P.A. Egelstaff. Pp. xvi q- 236 + Ill. (1967) Academic Press, London, New York. 57/6. $10. Properties of the crystal lattice or ooe a dilute vapour are reasonably well explained by their ideal state models, or through definable deviation from this ideal no such convenient approximation exists for the liquid state. This book progressively examines correlation of theory with generally limited experiment for molecules in their liquid phase deliberately no attention is paid to relative motion of atoms within the molecule. The monograph comprehensively demonstrates how, for any important function, a quantitative relation may be deduced from fundamental quantum mechanical principles. The text is organised into a series of compact chapters each containing a number of short sections briefly deriving or developing a specific concept within a pattern laid down at the beginning of that chapter. Although produced in a logical and cumulative sequence, as far as possible the chapters are self-contained, and to this extent the table of contents is itself a convenient general index to facilitate retrieval of specific