VOL.9, No. 1
RECENT BOOKS
apply physical chemistry t o the problems of biology. The author has adopted a research point of view which is helpful to the student in applying physical chemistry as a valuable tool in carrying out biological investigations. I n the chapter on surface tension, it is regretted that the author does not make mention of the relation of surface tension in the modern theory of cell antisepsis. I n the same chapter mention is made ' of the fact that sodium salts form oil-inwater emulsions and calcium salts favor the formation of water-in-oil emulsions. The antagonism of sodium and calcium in biology is pointed out. It should be mentioned, however, that this antagonism of inverting emulsions is not a specificity of the calcium ion but the same condition would obtain with magnesium and other divalent ions. Reference to Harkin's theory of orientation would aid the students in understanding the phenomenon of emulsions and emulsion reversibility. The reviewer feels that the matter of buffer capacity is not treated a t as great a length as it should be in a treatise of this kind. Its many references to biology, both in the plant and animal kingdom, are neglected. I n the mind of the reviewer the paragraph on errors tolerated in the calculation of pH would be made plainer t o the student if a table showing the relationship between hydrogen-ion concentration and pH were included. Furthermore, i t might he advantageous to emphasize that a difference in pH units in the neutral region of the pH scale is of less significance than the same numerical change on the extreme acid side of the scsle. Oftentimes this f a d is difficult for students t o grasp. The author fulfils his purpose in writing this book, that is, to present a practical working text in physical chemistry for students of biology. His style is precise and direct, and the student is not inundated by the mathematics presented by the author. J o m C. KRIINTZ,JR. STATE D s ~ ~ n r r a wo*r HRALT" BALTIIORE,MASYLIND
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Photochemistry. D. W. G. STYLE,Ph.D. With a preface by A. J. ALLMAND, M.C., D.Sc., F.R.S., Professor of Chemistry in the University of London, King's College. E. P. Dutton and Company. Inc., 96 pp. New York City, 1930. v 9 Figs. 16.5 X 10.5 cm. $1.10.
+
This little volume is designed t o afford an approach to the subject of photochemistry for physicists and chemists who have interested themselves little in the subject. The author has succeeded admirably in attaining his purpose and one feels safe in remmmendjng this work not only t o those who pretend t o know nothing about the subject, although possessing a good background of knowledge in chemistry and physics, but likewise t o photochemists. The style is clear and readable and one cannot fail to acquire a stimulating point of view on many problems. The book is divided into five chapters. The Introductory Chapter rovers the general laws governing light absorption as well as an elementary treatment of certain phases of spectroscopy, thus providink the reader with a hasty survey of the action +radiation on atoms and molecules. The following chapters deal with The Primary Light Process; Secondary Chemical Processes, Chain Reactions; The Dependence of the Quantum Yield on Temperature and Wave-Length; and Experimental Methods. A very short bibliography is appended The author has accepted the Bohr atom as being adequate for a qualitative description of many processes of interest to the photachemist and introduces the viewpoint of Franck in discussing light absorption by molecules. No mention is made of the subject of wave mechanics either as applied t o spectroscopy or as applied to collision processes. I n some respects the inclusion of the viewpoint of the newer phases of quantum mechanics might have been desirable. The book is written essentially from the chemical side and one has the feeling that many of the intimate pictures of reaction mechanism, particularly as regards reaction
198
JOURNAL OF CHEIdICAL EDUCATION
in solution, may require revision as mare exact mathematical formulation of the laws governing such processes is obtained. The author has, however, been unusually candid in his treatment of doubtful points and the reader should acquire a thorough appreciation of the weak points in certain of the mechanisms discussed. The book is remarkably free from typographical errors and those which do occw; together with some slight inaccuracies in statement, do not detract seriously from the value of the work as a whole. The book may be recommended either for relatively light reading or more serious W. ALBERTNOYES,JB. study. BROWN UN~YGRSITY
Paovromce. Rnoos ISLAND
Merck's Index, an Encyclopedia for the Chemist, Pharmacist, and Physician. Fourth edition. Merck and Co., Inc., Rahway, New Jersey, 1930. iii f 585 pp. 15.5 X 23 cm. $5.00 in general. $2.50 t o members of the chemical, pharmaceutical, medical, and allied professions. The fourth edition of Merck's Index is a welcome volume t o those who have enjoyed the privilege of using this hook in its former editions. The book contains five hundred and fifty-seven pages of short yet useful monographs on chemicals, botanicals, and drugs. Each of these monographs gives the names and synonyms; the sources; origin or mode of manufacture; chemical formulas; and molecular weights; physical characteristics; melting and boiling points; solubilities; specific gravities; medicinal action; therapeutic uses; ordinary and maximum doses; incompatibilities; antidotes; and methods of storing. A special feature which enhances the usefulness of this book is the ease with which i t can he used. There are no special codes and systems required t o manipulate the Index. The substances are arranged in alphanoss-inbetical order and thoroughly . dexed. Its supply of common synonyms of various drugs is especially commend~
JANUARY, 1932
able. I n addition to the book's serving as an index for drugs and chemicals, there are included several tables giving the characteristic readions of alkaloids, g h cosides, acids, bases, metals, and salts, along with specific gravity tables. TR. JOFIN C. KRANTZ.
Nucleic Acids. P. A. LEVBNE, The Rockefeller Institute for Medical Research; W. BASS,Mellon Instiand LAWRENCE tute of Industrial Research, now Assistant Director of Research, The Borden Company. The Chemical Catalog Co., Inc., New York City, 1931. 337 pp. 14 Figs. 15 X 23 cm. $4.50. At the present time, more and mare research is being undertaken with the express purpose of learning mare about the chemistry of the cell. These investigations range over the whole field ofchemistry, from physico-chemical determinations of membrane equilibria to the isolation and identification of the organic compounds which go t o make up the cell+ The cells studied range in size from the scarlet fever streptococcus, whose diameter is of the order of one micron, t o certain cells found in tropical waters which get t o be as large as a hen's egg. I n view of this ever-increasing interest in cell chemistry, i t is peculiarly fitting that this volume on nucleic acids should appear a t this time, dealing as i t does with a class of compounds which are tvuical of and are found onlv in cell .. nuclei. The authors have taken ur, the subiect matter in a very logical and orderly manner. As the nucleic acid contains in its molecule phosphoric acid, sugar, and various nitrogenous bases, an understanding of its chemistry is impossible without a working knowledge of its component pa*. Accordingly, the first five chapters deal with the general chemistry of the sugars, purines, and pyrimidines, giving special attention, however, t o those individuals which occur in the nucleic
