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Chemical Education. The first chapter gives a review of electroanalytical methods. The second chapter describes a simple and inexpensive manual apparatus for carrying out quantitative measurements with the drop6ing electrode. Most of the apparatus is available in well-equipped chemical laboratories. The following two chapters deal with fundamentals of quantitative and qualitative polarographic analysis. The various factors determining the diffusion current (IlkoviE equation), the significance of the halfwave potential, and the analysis of waves are adequately discussed. The last chapter reviews several applications of polarography. The booklet is well and concisely written, and i t is well suited as an introduction to the subject of polarography. Its reading is recommended to students and teachers. On page 66 the author mentions that the “capillary constant” can be determined by collecting the mercury while dropping in air. However, in experiment 8 he gives directions for collecting the drops falling in dilute potassium chloride solution. On page 87 i t is stated that if the unknown is more concentrated than 10-*M, it is usually possible to work with the solution open to air. However, in many cases, the flat second wave of oxygen interferes with the measurement of diffusion currents. The statement on page 98 that a mixture of thallium and cadmium in 1 N potassium cyanide gives only the cadmium wave is incorrect. On page 113 the author states that polarometric titrations have the same shortcomings as sonductometric titrations. However, he overlooks the fact that amperometric titrations can be carried out in the presence of large amounts of indifferent electrolytes, whereas under the same conditione conductometric titrations become much less accurate. I. M KOLTHOFF.
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Practical Physical Chemistry. By ALEXANDER FINDLAY. 54 x 8+ in.; x 335 pp.; 124 figures. London, New York, Toronto: Longmans, Green and Company, 1911. Price:
$3.00. This book has gained a well-deserved popularity, as witnessed by the publication of the seventh edition since 1908. In several respects it is quite evident that the first edition dates back to the beginning of this century. Many experiments of the classical type are given which are not found in more modem books of the same character, whereas methods of more recent development (e.g., abridged spectrophotometry with photoelectric reading, dielectric constant, etc.) are not given. Although several additions have been made to the present edition, modem developments in physical chemistry have not always been given due considerstion. This is especially true of the subject of the modem theory of electrolytes (the calculation of the activity from osmotic measurements on page 133 is not correct; Onsager’s equation is not mentioned in connection with equivalent conductance). A new feature of the book is the introduction of the antimony electrode for pH measurement, but the glass electrode, which is much more exact and which fin& much wider application, is omitted. I n a modern book the Langmuir adsorption isotherm a t least should be mentioned in connection with the empirical Freundlich expresclion (page 319). I n spite of its limitations, the new edition, aa its predecessors, excels from the educational viewpoint. The description of the fundamental theory and of the procedures is clear and more than adequate to enable a student to carry out the experiments without much aasiatance. I. M. KOLTHOFF.
Advance8 i n Enzymology and ReEafed Subjects. Vol. I. Edited by E . F. NORDand C. H. WERKMAN.6 x 9f in.; x 433 pp.; 56 illustrations. New York: Interscience Publishers, Inc., 1941. Price: $5.60. The Editors have undertaken to assemble internationally recognized authorities to assure expert presentation of the latest developments in enzyme chemistry aa well as related fields. This field has been developed a t such a rapid pace in recent years that
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comprehensive reviews such as collected here have become most valuable for the worker in the field as well as for the student. Advances in Enzymology takes up thus the fine tradition of the now defunct Ergebninse der Enzymforselung established under the editorship of F. F. Nord. The first volume of this series consists of a collection of ten independent monographs. Problems involved in the elucidation of protein structure are reviewed by Henry B Bull, while Luise Holzapfel considers physicochemical viewpoints in connection with the action of virus proteins. The chapter on the specificity of proteinases, by Max Bergmann and J. S. Fruton, is a very instructive and clearly written presentation of problems encountered in the biological process of peptide synthesis and peptide hydrolysis. The formation of energy-rich phosphate bonds during the metabolic phosphate cycle is discussed by Fritz Lipmann, and the widespread utilization of such phosphate bonds as a source of energy for organic chemiaal syntheses, bone formarion, and mechanical work during muscular contraction is pointed out. The chemical nature of catalase is reviewed in an excellent article by Sumner, contributing a good deal of hitherto unpublished data out of the writer’s laboratory. “Enzymes and Trace Substances” is the title of D. E. Green’s monograph, in which the r61c of vitamins, hormones, and metals in enzymatic processes is summarized. Facts and interpretations of intricate problems involved in photosynthesis are reviewed by Frank and Gaffron. while a second article by Van Niel deals more extensively with bacterial photosynthesis. Enzymatic processes within the living plant are discussed by A . Kurasanov, and an interesting attempt is made to correlate the ratio of synthesis to hydrolysis with the distribution of the enzyme between the solid and liquid phases of the cell. H. J. Vonk deals with problems of digestion in lower vertebrates. Anatomy as well as cnzymology are considered and compared with the digestion in higher vertebrates and in vertebrates, respectively. ERWINHAAS.
Advances i n Enzymology and Related &‘ubjccts. Vol. 11. Edited by E. F. NORDand C. 374 pp.; 23 illustrations; 31 tables. New York: InterH. WERKMAN.6 x 9+ in.; viii science Publishers, Inc., 1942. Price: $5.50. Fifteen authors eminent in their field have contributed to the second volume of this serics of independent monographs which already has become indispensable for any biological library. I n the contribution of Max Bergmann, attempts are made to classify proteolytic enzymes tentatively on the basis of structural requirements in the substrate. The mechanism of proteolytic enzyme action is discussed according to their activation by metals, sulfhydryl compounds, and hydrocyanic wid. The importance of coupled reactions in the decomposition of peptides by proteolytic enzymes is stressed, and interesting possib mentioned regarding the rOle of coupled reactions in biological synthcsis of proteins or in the action of viruses. In the chapter on the enzymatic properties of peptidases, by Marvin J. Johnson and Julius Berger, the authors have stated the present knowledge on peptidase systems occurring in animal organs, yeasts, higher plants, fungi, and bacteria. From specificity relations towards certain substrates, or from the activation of enzyme systems by metals and reducing agents, preliminary conclusions may be suggested as to the similarity of peptidases from different sources. The necessity of isolation of the pure ellzymes for elucidation of the action of the peptidases is pointed out. The kinetics of hydrolytic enzymes and their bearing on methods for measuring enzyme activity are discussed by Donald D. Van Slyke. On the basis of recent experiments on arginine hydrolysis conducted in the writer’s laboratory, as well as on classical experi ments by Michaelis and Menten, Van Slyke and Cullen and others, the two-phaae law
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