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and a summary of the researches on the explosive properties of Leunasaltpeter after the disastrous explosion a t Oppau. It appears t h a t the salt can be exploded b y violent detonation, the explosibility falling rapidly with increase of cubic density. The sectiou on the technical production of ammonium salts is too brief, occupying only t e n pages, although i t is perhaps the best short survey available. It is t r u e t h a t ammonia synthesis has been fully dealt with in a previous volume and t h a t the authors give some reasons for the very brief treatment, y e t the reviewer feels t h a t many readers will be disappointed by the sketchy character of the text, as compared with the exhaustive detail given in other volumes on purely physical properties of little chemical interest. For example, although the recovery of by-product ammonia is treated, there is no mention of the very important question of purification, particularly from pyridine. T h e reviewer thinks attention should be drawn t o this tendency t o limit the purely chemical side at the expense of the physicochemical, or even of pure physics, and t o express the opinion t h a t it is not advantageous t o the n-ork. H e has, before expressing this opinion, read the justification given by the authors for their procedure.
J. It. PARTINGTON.
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Enzyme Chemistry. By HESRYT-AUBER. 15 x 23 em.; xii 241 p p . ; 28 figs. S e w T o r k : John \Tiley and Sons, Inc., 1937. Price: $3.00. T h e fact t h a t most physical chemists are interested in the phenomena of catalysis and t h a t enzymes are probably the most important catalysts known t o the chemist justifies a brief review of this volume in a journal devoted t o physical chemistry. The author defines enzymes as “catalysts a.hich are produced by the living rell, b u t whose action is independent of the living cell, and which are destroyed if their solutions are heated long enough.” H e adds that there are two other classes of biochemical catalysts which he does not classify as enzymes. I n one class he places those “catalysts produced b y the living cell, active i n vitro as well as i n vico, their activity, however, depending upon the unimpaired cell. They are destroyed on heating and their activity ceases on mechanical destruction of the cell. Examples: the catalyst affecting the synthesis of urea in the liver, and the dehydrogenetic fucction of certain bacteria.” I n the third class he places those “cxatalysts elaborated by the living cell, their action being independent of the living cell. They are n o t destroyed vihen their solutions are heated. Examples: glutathione, ascorbic acid.” I n the preface the author frankly states t h a t he makes no claims t o have exhaustively dealt with the subject of enzyme chemistry or t o have duplicated material available in earlier monographs. Instead he desires t o present some of the more recent advances in the field. I n this respect the reviewer feels t h a t he has been very successful and t h a t the prospective reader may safely purchase this volume; by perusing it he will become familiar with the direction of modern thought in explaining enzyme phenomena and with what has been achieved in the chemistry of enzyme reactions. T h e volume is divided into eleven chapters, as follows: Introduction and General Considerations; Esterases; Proteolytic Enzymes and Peptidases; Amidases; Carbohydrases; Catalase; Oxidizing Enzymes; The Flavin Oxidation System; The Zymase Complex and Alcoholic Fermentation; Carbonic Anhydrase; and Luciferase. Complete citations, including titles of papers, are given t o 796 literature sources. The text, in conjunction with these references, makes the volume well adapted for an advanced course in enzyme chemistry, supplemented, of course, with other material which the lecturer would provide. For those whose fields lie outside of enzyme
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chemistry it affords an excellent prospective of recent trends and advances in the subject. Ross AIKEXGORTNER.
Praktische Einfuhrung in d i e physikalische Chemie. Erster Teil: Moleh-uleund Krafte. By KARLLOTHAR WOLFand HANS-GEORG TRIESCHMANN. 22 x 14 cm.; viii 114 pp. Braunschweig: Vieweg & Sohn, 1937. Price: unbound, 4.50 hl. This introduction t o practical physical chemistry, of which the present volume forms the first part, is planned for the future advance of the science. A wide interpretation is given t o chemistry. The text is divided into theory, exercises based thereon, partial experiments (being either short tests or allusions to fuller investigations for which references are given t o well-known textbooks) , and actual work t o be carried out. The experiments in the last category, of which there are forty-four, include, in addition t o the usual routine of practical physical chemistry, the determination of the characteristics of a valve, the photography of Rnman spectra, extinction coefficients, para- and dia-magnetism, and measurement of the viscosity of gases. Thus the treatment of the subject is novel and opens u p new ground; it would bewilder the average student who used it as a s t a r t for his work, but it should prove interesting and serviceable to those with more mature knowledge. \v. H. P.4TTERSOS.
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Katalytische Umsetzungen i n homogenen und enzymatischen Systemen. By W. FRASKENBURGER. 444 pp. Leipzig: Akademische Verlagsgescllschaft, m.b.H., 1937. Price: 36 RM. -4little more than a hundred years ago Berzelius (1835) introduced the word “catalysis” and defined a catalyst as a substance which affects the rate of a reaction without occurring in the stoichiometric equation. It is a tribute to Berzelius’ vision that this definition, presented a t a time when nothing was known of the kinetics and mechanism of catalytic reactions, still holds a t present. Frankenburger’s book revien s our past and present knowledge of homogeneous and microheterogeneous catalysis. I t includes an introduction of 55 pages, in which, after a short historical development, a modern review of reaction kinetics is given. Homogeneous catalysis (in gaseous and liquid phases) constitutes the main bulk of the book, and the last 100 pages are devoted t o enzymatic reactions which are of primary importance in biology. Considering the wide field covered, the book is of interest not only to chemists, but also t o biologists. The book is outstanding regarding the kinetics of the various reactions, which are presented in a modern fashion and can be understood by readers who have no mathematical background. A great number of catalytic reactions are discussed in detail, and numerous references t o the literature are found. On the other hand, one misses a comprehensive treatment of our present views of certain particular subjects. Acid-base catalysis (100 pages), for example, cannot be well understood without a modern picture of acidity and basicity in general, and particularly of the medium effect. In this part one also looks in vain for a discussion of Hammett’s “acidity function” and its usefulness in the kinetic analysis of various acid-base catalyses. I n the discussion of oxidation-reduction catalysis no mention is made of a selection on the basis of free energy relations of substances which may have a catalytic effect. In spite of these limitations the book is strongly recommended to those interested in catalysis from the chemical or biological viewpoint. I. 31. XOLTHOFF.
