MAY. 1950
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that the frozen mass could he heated during sublimation, without melting, the heat provided being utilized so rapidly st the evaporating surface of the ice that the temperature of the frozen mass might still be retained at such a temperature as -20°C. This application of heat shortened the time required for the removal of the ice from days to hours, and was the necessary step in making the process practical. A rapid development followed and is continuing. Freeze-drying, the author shows, is applicable to various foodstuffs, although its expens-relatively minor in the preparation of high cost biologicals-becomes a seriously inhibiting factor. A thorough bibliography is appended to each chapter, a patent list is given, and, in an appendix, work done on the process a t M.I.T. durine the war is summarieed. and the use of freeze-drying . in the prepar&ion of anrutamieal spe&ens is described. The book can be recommended to all who are involved in research on biologicals, to all who are interested in a development which made possible the widespread use af serum, plasma, penicillin, and the like, and to those actually applying the process in industry. Chemists with imagination may also perceive possible applications to the isolation of unstable compounds or to the crystallization of those which tend to resist that procedure. J. E. CAYELTI Amr;onar*uC o r ~ k a a MEADVIGL.,PGNNBTLYANIA
PRINCIPLES OF ORGANIC CHEMISTRY James English, Jr., and Harold G. Cassidy, Assmiate Professors of Chemistry, Yale University, New Haven, Connecticut. International Chemical Series. McGraw-Hill Bwk Co., Inc., New York, 1949. xiii 512 pp. Illustrated. 16 X 24 cm. $5.
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T m s textbook for a year course in organic chemistry is written from a somewhat more theoretioal point of view than are most similar texts. The terms electropbilie and nucleophilic are introduced emly and used repeatedly. Possible mechanisms of reaetionsrarementionedfrequently. In fact, aslightly theoretical point of view is maintained throughout, even though the subject matter a s s whole is pretty much what we have come to expect. The hook opens with a short introductory chapter, largely of a. theoretical nature. I t is less extensive in scope than similar sections in tents that have long been well known. But whereas some of these sections have been little more than introductions to a traditional trest,ment of organic chemistry that from there on differed little from the presentation used for decades, this textbook uses constantly and even expends the limited theoret,ical material with which it opens. The following six chapters (106 pages) are devoted to the hydrocarbons, including aromatics. Chapters 8 to 19 cover simultaneously the aliphatic and aromatic members of the various common functional classes, starting with alcohols and phenols and ending with amino acids. C h p t e r 20, "Color and chemical constitution," is quite brief and draws the illustrative material largely from t,he field of quinones. Chapters 21 to 24, "Stereoisomerism," "Carbohydrates: the sugsrs," "Macromolecules: polysaccharides, proteins, and plastics," "Topics in biochemist,ry," are adequate but, except for the sugars, rather brief. The authors have wisely taken the stand that since this is a textbook and not a reference book, it should not contain more material then can reasonably be covered in a year course. Anyone, therefore, is likely to find some of his pet subjects missing. For the most part, however, the important basic material is certainly ~resented,the pruning having been done largely on the special topics type of material. As interesting as such material is, there is no real reason why an elementary organic chemistry textbook must contain extensive sections on natural and synthetic drugs, alkaloids, dyes, hormones, vitamins, terpenes, heterocyclic compounds, and sterols. There me many excellent references, pertinently and con-
cisely annotated. As usual, some will he useful mainly to the teacher, but many are suitable for student reading. The exercises are unusually numerous and seemingly very carefully compiled. The reviewer has long believed that most organic chemistry texts have been deficient in this respect. Students learn best by practice, and practice is more efficient when guided. Many of the exercises are of types commonly used in courses in qualitative organic analysis. I t is quest,ionable how much the average student in a first year course o m profit by some of these. The emphasis on this kind of exercise may be advantageous in courses with laboratory work consisting to a considerable extent of identifying organic compounds and separating mixtures of them. I t will he less helpful sud less meaningful in courses where the laboratory work consists larzelv - . of orwara. . tions. The authors deserve congratulations for having produced a book that is relativelv free of errors. A fair nro~ortionof tho* spoucd by r l w reviewer nwe in conuertim wirh systematic ~lllmcnclnturu,the lrcnrnicl~tof a.l&4l, irrv~&ntnlly.dren sccnrs insdequrre. Sinec the Inrgcsale iudusrri.*lu~ilir!rirmof such 2 process must be well known to the authors, it is interesting to speculate on what they might have had in mind when they wrote the statement on page 181, "Direct halogenntion. Not applicable in aliphatic series." Unfortunately, there seem to be no statements elsewhere in the book that would clearly correct the erroneousimpression that this issure to makeupon thestudent. This hook should be seriously considered by any teacher who wants a rigorous presentation of the fundzmentsls of organic ehemistrv from a somewhat theoretical point of view without too many frills, and who does not object to teaching aliphatic and aromatic compounds simultaneously.
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LAWRENCE H. AMUNDSEN U r r v e n a ~ rOF CONNECTICUT S ~ o n n sC o l r r s c ~ ~ c u r
ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY. VOLUME IV: CINEOLE TO DEXTROSE Edited by Raymond E. Kirk and Donald F. Othmer, Professors and Heads, Deparhnents of Chemistry and Chemical Engineering, respectively, at the Polytechnic Institute of Braolrlyn. Assistant Editors, Jonet D. Scott and Anthony Standen. The Inter969 pp. science Encyclopedia, Inc., New Yark, 1949. xvi 19 X 27 cm. $20.
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THEindex letter "C" finally ended with a discussion of cyclohexanol and cyelohexanone; a total of 1947 pages devoted to this one index letter. As mentioned previously, because of the high quality of the articles no one will object to an increased coverage or increased number of volumes over the ten that were scheduled for the set. Some of the longer sections in Volume IV are: citric acid, clays, coal, coated fabrics, industrial coatings, cobalt and its compounds, coffee, colloids, color, colorimetry, columbium, conductometry, confectionery, conveying, coordination compounds, copper and its alloys and compounds, corrosion, cosmetics, cotton, cottonseed, orystaIlization, crystals, cyanamides, cyanides, cyanine dyes, oyclohexaue, dairy products (73 pages), datainterpretation and correlation, density, dental materials, detergency, and dextrose. The section on Data-Interpretation and Correlation by Prof. D. F. Othmer is particularly noteworthy. For the first time his method of making reference substance plots, which has been a p pearing as journal articles since 1940, is gathered into one article. The wide variety of topics covered in E. C. T. becomes more impressive as the volumes increase in number, so that their utility and need by students becomes greater. The library in the small college cannot afford to be without this set, for it will serve a large group of reference users. KENNETH A. KOBE Umvansmr on T s x ~ s
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