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REVIEWS 857 Reviews FOOD TABLES. By V. H. MOTTRAM and ELLEN M. RADLOFF. Pp. 63. London: These tables should be of wide use not only to the dietitians or “nutritionists” for whom they appear to be primarily intended by the authors but also to all those who have from time to time to concern themselves with the composition of individual foods or of meals and dietary regimes. The authors have very wisely in my opinion ignored certain classical and established figures and pinned their faith to results obtained by some of the more recent methods of analysis. It is refreshing for example to find that in several places they have called attention to and given figures for the difference between phytin and non-phytin phosphorus; since the phytin phosphorus of many foods is possibly not utilised at all in the human gastro-intestinal tract the amount present in a food may be of botanical rather than of dietetic interest.A distinguished member of this Society reviewing these Tables elsewhere, has criticised the authors for giving values to a number of “significant figures” that they themselves admit to have no significance. The authors explain in their Preface that they have given the figures as determined frequently by calculation from other figures although they are fully aware that practical nutritionists should and in most instances will use rounded off figures. Why asked that reviewer give these meaningless numbers at all ? There is no simple answer to this question which seems to me to overlook what is really the guiding principle.There have always been among analysts two schools of thought on this matter the one school insisting that only those figures should be given that have statistical significance allowing for the precision of the methods used and the other insisting that the figures to be reported should be based upon the figures found whether or not the last one or two of the reported figures are indeed significant. Surely the answer is that the latter figures should in fact be published in such places as the columns of THE ANALYST when the reader is himself an analyst or at least a chemist and is capable of judging for himself of the significance of the figures. On the other hand where the information is intended for those less analytically expert who are to some extent likely to be misled by them rounding off is not only justified but desirable.I am inclined, therefore in this particular instance to agree with my fellow-member reviewer, for it is certain that these valuable Tables will find their greatest use outside the circle of professional analysts. Besides protein fat and carbohydrate contents for most of the large number of foods included in the 54 pages of the tables the calorific values and the contents of calcium phosphorus and iron are also given. Moreover all of these have been calculated not only for 100-gram portions of food but also for 1 oz. 4 oz. and 1 lb., thereby saving the practical dietitian a deal of arithmetic. The distinction recognised by the authors between phytin and non-phytin phosphorus has an interesting analogy in the difference between easily available and poorly available iron on which matter the publications of McCance and Widdowson may be consulted.It is hoped that in subsequent editions Professor Edward Arnold & Co. 1937. Price 5s 858 REVIEWS Mottram and Dr. Radloff may be able to call attention to the proportions of “dipyridyl” iron in many of the more important foods. There is one other matter that might receive attention in subsequent editions. A t several places in the tables figures appear in italics. On page 9 it is made quite clear what the italicising indicates but the authors seem to have become less alert as they went on. The next set of italic figures appears on page 22 and their meaning can possibly be found by analogy with the earlier. The same applies to those on page 25.Those on pages 28 30 37 and later have presumably also the same meaning but it would be very much better if they were all covered by a note in the general introduction. Incidentally if the figures were rounded off in the manner already suggested there might be room for a further column in which could be inserted figures for say magnesium or some other element when it is of particular importance in a particular food. It would be pleasant to see the barium content of Brazil nuts recognised here if only as a tribute to Mr. Seaber’s pertinacity . A. L. BACHARACH QUALITATIVE AKALYSIS FOR STUDENTS OF PHARMACY AND MEDICINE. By CHARLES B. JORDAN Ph.C. M.S. D.Sc. and HENRY GEORGE DEKAY, Ph.D. Second edition. Pp. xii + 178. New York McGraw-Hill Book Co.Inc.; London McGraw-Hill Publishing Co. Ltd. 1938. Price 15s. The advent of a new text-book on elementary qualitative analysis or even the revision of an old edition requires some justification especially when comparison with a standard text-book published in 1909 indicates how little the scheme of analysis has changed since that time. In fact one of the few reasons that would justify the publication of such a book is a definite need existing among a particular group of students. This need is presumably felt to exist among students of phar-macy and medicine and the book may quite properly be regarded as meeting their requirements and should make an appeal to them that the merely chemical text-book does not; for the importance in pharmacy of many of the reactions used in the conventional scheme of qualitative analysis is emphasised throughout.Thus, several of the incompatibilities met with in dispensing are explained as are the reasons for the use of certain chemicals as antidotes to poisons. Moreover, constant reference is made to the contents of the United States Pharmacopoeia and the National Formulary so that the student can see the practical application of many of the things he is asked to do. The theoretical background of the book is sound and it may be said to be written around the concepts of ionisation and solubility product. Unfortunately two criticisms may be levelled against it : first the price is too high for a book of this type; secondly more attention might have been paid to the newer “spot” reactions.I t may be difficult to modernise a subject that has hardly changed in thirty years but the only “spot” reagents that find mention are aurin tricarboxylic acid a-nitroso-P-naphthol and dimethylglyoxime. So many are in common use to-day that it seems a pity to have missed the opportunity of referring to them Incidentally chemical historians should note the final departure from the analytical scene of blowpipe analysis; even Thenard’s blue is now made on burnt filter-paper instead of on the once-popular charcoal block ! F. A. ROBINSO REVIEWS 859 AN INTRODUCTION TO MICROCHEMICAL METHODS. CECIL WILSON B.Sc. Pp. xi + This book as its title states is intended as an introduction to microchemical methods for senior students of chemistry and as such fulfils its purpose admirably.It is clearly and simply written and the beginner obtains the impression that the micro methods are as easy to learn as those of the normal laboratory scale which indeed they are. As the book is intended for student beginners the author devotes half the space to the use of the microscope for observing physical properties and the results of crystal tests. A short chapter is devoted to a few typical spot tests without however any reference to the precautions necessary in the presence of interfering ions. A useful chapter on inorganic qualitative analysis includes complete separation tables for most of the commoner ions. The filter-stick procedure for inorganic quantitative analysis and a few examples of its application in the estimation of barium phosphorus nickel and copper and two examples involving a separation are given.The uses of the tintometer colorirneter, spectrograph and nephelometer and the practice of photomicrography are briefly described. The chapter on organic preparative methods is well written and illus-trated. As the book is intended to be introductory only two pages are devoted to organic quantitative analysis. Within its scope the book is excellent and may be found of use to teachers of chemistry. THE SOYBEAN INDUSTRY. By A. A. HORVATH D.Sc. Pp. vi + 221. London: The Foreword to this book describes the author as a research worker and practical technologist in the soybean industry and he has provided perhaps the most comprehensive treatment of the subject in our language. Practical details of many of the manufacturing operations are included.The soya bean has now become the source not only of a valuable oil and a food for cattle but of numerous products of industrial importance. After dealing with the edible oil and flour and the technical uses of the oil the author describes the commercial extraction of Fhosphatides (mainly lecithin and cephalin) from the beans and the employment of these substances as emulsifiers in foodstuffs and for a variety of purposes in the manufacture of soaps cosmetics and paints. Then follows an account of the production of soy protein and its use in the manufacture of plastic products and of the commercial preparation of detergents sizings and adhesives from the solvent-extracted meal. When manufactured from shelled beans whole soya bean flour contains on the average about 40 per cent.of protein 20 per cent. of oil and 3 per cent. of phosphatides. By treatment with steam the resultant flour is freed from the “bean” flavour (mainly due to methyl-n-nonyl ketone) and since the enzymes are thereby rendered inactive a flour of good keeping quality is obtained. Soybean oil is obtained by pressure and by solvent extraction the latter method having been greatly developed in recent years in order to obtain the maximum yield of oil. The extracted meal is less liable than the “press meal’’ to develop rancidity and is a more satisfactory stock food. Moreover the meal can be more advantageously used for industrial purposes. The various extraction 196 with 93 diagrams. London Methuen.1938. Price 7s. 6d. J. W. MATTHEWS E. & F. N. Spon Ltd. 1938. Price 16s 860 REVIEWS methods are described the most commonly-used solvent being a petroleum spirit of boiling range about 52” to 93” C. Ethylene dichloride is a suitable solvent as are mixtures of benzene or petroleum fractions with trichloroethylene. The last-named solvent however has pronounced toxic properties. This book is commendably free from typographical errors but its price seems rather excessive. ARKOLD R. TANKARD TABLES OF REAGENTS FOR INORGANIC ANALYSIS. First Report of the “Inter-national Committee on new Analytical Reactions and Reagents” of the “Union Internationale de Chimie” (in English German and French). Pp. xxiv + 409. Leipzig Akademische Verlagsgesellschaft m.b.H.1938. Price RM.36 bound; RM.34 unbound. It is the work of an International Committee whose members are acknowledged authorities on the newer analytical chemistry. It is slightly annoying though quite unimportant that the only bit of consecutive writing in the book the Preface however good it may be in German and French is in the English version a precise and painful translation. This book, however is not literature but a piece of apparatus; and judged as such it is well made and useful. It is essentially a trilingual tabular summary of spot reactions, drop reactions and other highly sensitive qualitative tests for cations and anions, including all such tests discovered between 1910 and 1936 and a selection of those known earlier. As the Committee remark in their Preface the newer drop reactions and spot tests are much less known and used than they deserve to be largely because their number is so great that it is very difficult for the average chemist who can devote but a limited time to the study of technique even to look up let alone to evaluate critically the tests which might best serve his purpose.The Committee therefore decided very wisely in the reviewer’s opinion that the interests of chemists generally would best be served by publishing their compilation without delay, even though they recognise that a longer period of preparation would have in-creased the critical value of their work. The Tables list the known tests for each ion giving for each test (a) the reagent and an indication of its mode of use (b) the type of reaction (whether a precipitation or a colour test etc.) (c) the phenomena of the test ( d ) its sensitivity (e) remarks (which indicate inter alia interfering ions and the Committee’s opinion of the test) and (f) references to the original papers or books where the test is more fully described.The comprehensive character of the list may be inferred from the fact that some 1600 separate tests are given for the 58 cations and about 350 tests for the 38 anions. In order to keep this mass of material down to a manageable size and make it intelligible in three languages much use has been made of symbols and as a result the Tables look rather formidable a t first glance. The system of symbols however is so simple and sensible that it is very quickly grasped and its use certainly makes it easy to see at once the essential features of each test To the busy chemist who occasionally needs to find quickly a convenient and sensitix-e test for some unusual substance this Report is invaluable because in i t To describe this book is to commend it REVIEWS 86 1 he can learn in two or three minutes what would take him as many hours to hunt up in the Abstracts.The Committee is authoritative and one need not hesitate to rely upon the tests they remark as “recommended,” or to pass over those marked “not recommended.” On the other hand for those who are specially interested in the critical study and development of microchemical tests it is very useful to have at hand so complete and compact a survey of their field. The utility of the Tables is considerably enhanced by an appended “Register of Reagents,” which is really an index whereby one can trace easily all the reactions given by each.The thanks of all chemists are due to the Committee for their arduous and unselfish labour for the common good and it is to be hoped that the success of these Tables will be such as to encourage them in the continuance of their valuable critical work. H. V. A. BRISCOE SCIENCE AND NUTRITION. By A. L. BACHARACH M.A. F.I.C. Pp. 149. London: The aim of this book (one of The Changing World Library Series) is to put before the reader “the kind of methods used in the laboratory study of nutritional problems and the kind of knowledge obtained thereby.” The treatment of the subject is intended to have a chemical rather than physiological tendency and the reader is expected to be in the main a “layman” or a “man in the street.” The book opens with a chapter on the use of animal experiment-not the ethical considerations but the ability of such experiments to give quantitative evaluations and an examination of the extent to which the animal experience may be translated into the human.There follows a section on “classical” nutritional science this being dealt with in chapters-carbohydrate chemistry carbohydrates in the body fat chemistry fats in the body protein chemistry amino acids in the body pure chemistry being followed by the physiological chemistry in each group. These chapters are the reviewer suggests made more difficult than they need be; they are certainly stiff reading.They might perhaps have been made more easy of understanding if a number of side issues had been avoided and a simpler more strictly connected account of the chemistry been given. As a test of the suitability of the treatment of a difficult subject for the man in the street the reviewer tried it on his wife-a course permitted by the Preface. In view of the maxim that none should conduct experiments save those who have done many it would be wrong to record precisely the result of this single trial; suffice it to say that it did disclose some fault either in the book or in the particular man in the street chosen. But indeed it is ungenerous to be critical of a gallant attempt to write organic chemistry for the general reader. There follow short chapters on the major mineral elements hormones and trace elements and then the dive into the vitamins takes place.Vitamins as one would expect are most interestingly and instructively dealt with; the methods of vitamin research are expounded and there is related how through the misty regions of biological assay there have emerged the several pure chemical entities which are vitamins or pro-vitamins. This part is short but deals with big issues and economics raises its baleful head. The author scorns a Watts & Co. 1938. Price 2s. 6d. Finally comes the consideration of diets not in detail 862 REVIEWS minimum a safe a normal and even perhaps a good diet he goes all out for the optimum diet which should be secured by a reduction in retail prices or an increase in wages or both.“The fact that such a diet is immeasurably beyond the reach of the average or even the best paid urban industrial worker is not germane to the purely dietary aspect of the problem.” Germane or not it is depressing to think that it is “immeasurably” beyond reach. And even an average sort of optimum diet though it may be too much for some is not apparently sufficient when the population is viewed as a whole. Statistically it is argued it can be shown that what is optimal for many must be sub-optimal for from a third to a half of the population; those on the lower side of the mode will be receiving their optimum or more while their less fortunate brothers on the upper side may come perilously near starvation. “It is surely better . . . that a dozen men shall be overfed than that one should starve to death.” The prescription of over-feeding is regarded by the author it is true, as a temporary measure and it is to be hoped that some more economical way of feeding the population may ultimately be devised.Professor J. C. Drummond too in the Preface which he contributes when referring to the very recent tracing of the cause of pellagra to a deficiency of nicotinic acid and contrasting the use made of this knowledge in two quarters of the globe says “It is not a question of nicotinic acid it is simply one of E s. d.” The annual cost of a generous daily prophylactic dose of calciferol for the child population of these islands (is millions) is given as &100,000. Infantile rickets could therewith be rapidly, completely and finally eradicated.This cost the author can “leave to the reader to evaluate in terms of bombers and tanks.” But the reader could make another evaluation; he could find that the annual cost per child is two-fifths of a shilling-the price of a modest pint. However it is for the future in which the present should play its part to decide how to answer social questions arising from the work of the scientists in recent years. In spite of the manifest difficulties which this book must present to the general reader it is to be hoped that it will be widely read; and there must be many disdaining to be called general readers in this sphere who could read it with great profit. It should cause all to think for Professor Drummond warns us in his Preface “The survival of democracy or its annihilation during the next few years may easily be determined by the measure of attention given in the various countries to what have come to be called the problems of human nutrition.” Not all dietary reforms however are expensive. Either evaluation is startling. Mr. Bacharach describes how this work has been done. E. HINK

ISSN:0003-2654    

DOI:10.1039/AN9386300857

出版商:RSC    

年代:1938

数据来源: RSC