BOOK REVIEWS Official and Tentative Methods of Analysis. 6th edition. i i i f 932 pages. Association of Official Agricultural Chemists, P. 0.Box 540, Benjamin Franklin Station, Washington, D. C., 1945. Price. $6.25. Ever since it was founded in 1884 the Association of Official Agricultural Chemists has devoted itself almost exclusively to studies in the field of methodology. Beginning with the standardization of methods for the analysis of commercial fertilizers, the scope of its work has expanded continuously to meet the ever-increasing needs of its members who are now concerned with the enforcement of laws and regulations relating to commercial fertilizers, stock feeds, food, drugs, cosmetics, insecticides, fungicides, caustic poisons, and other articles: or who are engaged in research in these and related fields. Each succeeding edition of the association’s text, which has come to be known by the short title “Methods of Analysis, A.O.A.C.”, represents the elimination of obsolete or little-used methods, revisions and improvements of other methods, and the addition of many new procedures. The 6th edition is notable for new chapters on cosmetics, gelatin, dessert preparations and mixes, enzymes, and extraneous materials in foods and drugs. A chapter on vitamins assembles under one head methods for vitamin assays previously scattered throughout the book under other titles. A mechanical improvement in the form of presentation is the use of Arabic numerals to designate chapters, with decimals for the subheadings therein. A special effort has been made to have the “selected references” cited a t the end of each chapter show, as far as possible, the original work upon which the methods are based. It is pertinent to note that these methods have acquired an added significance in recent years, since many of them are being incorporated in standards for food products promulgated under authority of the Federal Food, Drug and Cosmetic Act. This gives legal status to the procedures thus cited. Laboratory workers in this country who are engaged in official work within the scope of the association’s activities, and who comprise the active membership of the association, will welcome this new edition as an indispensable laboratory guide. So also will workers in like fields in foreign countries, among whom this text has come to have wide recognition and arceptance. E. M. BAILEY
Quantitative Organic Microanalysis. Edited by Julius Grant; 4th English ed. Based on the methods of Fritz Pregl. vii f 238 pages. The Blakiston Co., 1012 Walnut St.. Philadelphia. Pa., 1946. Price, $5.00.
The book under review has only 288 pages of text a8 compared with 271 in the previous edition. Despite this, more actual text is provided; this is achieved by better organization of material and by space economies in make-up. The older book had 27 chapters: the present, seven: Microchemical Balances, General Microanalytical Technique, Determinations of the Element$, Determinations of the General Groups, Determinations of the Physical Constants, Miscellaneous Physical Methods, and Calculations of the Results of Microanalyses. The author has made a real attempt to discriminate among alternative methods, giving first place to those he believes to be the best, even though they originated outside the Pregl school. But, as stated earlier, the reviewer believes that this policy might have heen pursued even more vigorously. Specific mention should be made of Chapter 111, wherein the sections of the determinations of the metals have been gratifyingly expanded. The book is modernized by brief mention, in Chapter VI. of the new techniques of electrometry, polarography, radioactive indicators, and ultraviolet fluorescence analysis. This is all to the good, as far as it goes: but it is hoped that the next edition will go much further. The indexes are much improved, and it is noted that the tables of gravimetric factors have been recalculated to take account of changes in atomic weights. For the benefit of those not familiar with other editions of Pregl, we quote from Dr. Grant’s Preface: “The needs of the beginner in microanalysis have been borne prominently in mind, although a background of knowledge of ordinary organic analysis is assumed.” This book is strongly recommended to all who have occasion to practice. teach, or study quantitative organic microanalysis. B. L. C L l R K E
CORRESPONDENCE Semimicrodetermination of Saponification Equivalent ~ I R : Ketchum (I) has devised a semimicromethod for the determination of the saponification number (or the saponification equivalent). In comparing his method with ours (9) he states: “The procedure of Marcali and Rieman is limited to compounds which are readily soluble in alcohol and which can easily be saponified.!’ This statement is not correct, as is proved by the successful application of our method t o eleven oils ( 2 ) , of which only castor oil is readily soluble in alcohol.
LITERATURE CITED
(1) Ketchum, D., IND.ENG.CHEM.,ANAL.Eo., 18, 273 (1946) (2) Marcali, K., and Rieman. W.. 111, Ihid.. 18, 144 (1946).
The third English edition of Pregl’s classical book, published in 1937, was, like its two predecessors, simply a literal translation of the corresponding German edition. I t was evidently felt that the Pregl text was sacrosanct. Now comes Dr. Grant, with what is stated to be not just another and better translation, but rather something between that and a new and original treatise on organic microanalysis. This seems to the reviewer to be a proper development. With all the great respect due to Pregl, there is no sense in continuing to pretend that he wrote the last word in organic microanalysis. The fact that he wrote the first words is sufficient to ensure him enduring fame. It is to be hoped that the next author to build upon the base estahlished by Pregl will be even more emancipated than is Dr. Grant from an obligation to classicism. Indeed, the reviewer’s only real criticism of Dr. Grant’s book is that he did not give nearly enough recognition to the hundreds who have followed Pregl. There was a time, not too many decades ago, when i t would have been heresy to write a book on general analytical chemistry that was not described in the flyleaf as based on Fresenius. We have long since got over that; and yet Fresenius’ fame as a pioneer has not dimmed. So let it he with Pregl!
Kutgers University New Brunswick, N. J
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SIR: In the sentence, “The procedure of Marcali and Riernan (3, is limited to compounds which are readily soluble in alcohol. .”, the word “readily” was employed only fn the loose sense in which the word is often used. It was not a good choice of word, but the sentence does not alter the main theme that my method has a wider application than theirs, because of the solubility limitations imposed by their method. This is illustrated by the fact that the ketones which were successfully analyzed Ey my procedure could not be run by their method because of the solubility limitations. When these ketones were mixed with only twenty times their weight of alcoholic potash they would not open the ring. DONALD KETCHUM Eastman Kodak Coinpans Rochester, N. Y .
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