MICROSCOPY FOR CHEMISTS Harold F. Schaeffer, Rensselaer Polytechnic Institute. D. Van Nostrand Co., Inc., New York, 1953. viii 264 pp. Illustrated. 15.5 X 23.5 cm. $4.50.
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A BOOK of this general title and purpose has been long overdue. l l ~ preface e quotes several well-known authorities on the importance of a microscope to the chemist and ends bv swine: ". .The
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author has endeavored to present the m a t e r i a L 6 be intelligible to the worker who must depend an his own resources without benefit of a mentor." The book is avowedly designed for the graduat,e chemist's self-instruetion. How well this objective has been achieved is uncertain. Part I(157 pages) has ten chapters of which the first five disouss elementary optics, the microscope, its oculars, objectives, and illuminution. These five chapters are quite good, although some of it could have been abbreviated for the graduate chemist. I t is unfortunate that the erroneous use of "depth of focus" for "depth of field" is perpetuated. Chapter 6 on Quantitative Microscopy is very suggestive and one wishes it were longer. Chzpter 7 on Polari~edLight could have been the most important in the book. Instead it sometimes discusses the trivial (e. y., the use of a cap analyzer in photomicrography) s t the expense of omitting the useful (6. g., the sign of elongation). It Uses the anachronism, "petrographic" microl;cope, instead of polarizing mictwscope, as most modern manufacturers do. This may mislead some cl~emists. Toward the end of Chapter 7 there are several confusing errors. For instance, Pages 109-10 ". . . .Those substsnces which exhibit oblique extinction are hiaxid. . ." is not true. In fact the author denies it himself on page 215 hy giving as examples of substances with parallel extinction some substances which are birtxial (picric acid) and then repeats the refutation again on page 216. A1.w on page 111 the statement, "A Maltese cross would indicate the presence of a. uniaxial substance," irr true only if no mica (I/, wave) test plate is used. And "This type of figure would $so exhibit two dots in diagonrally opposite quadrants" is only true if the mice plate is used. Figure 7.11, page 111, shows some uniaxial (Maltese cross) interference figures and same biaxial figures, both said to be obtained by using biaxial mica as the objeot. The chapter ends ". . .the laboratory manual explains how to obtain figures without the use of expensive scceswries," but the descrip tion an pages 213-14 is too brief for the inexperienced. Chapter 8 presents very briefly some miorochemical manipulationi and spends over a page explaining stem corrections of thermometers. C h a ~ t e9onInoreanic r Resctions mav, be suewstive for beeinners .t,ut only auggrrtivt.. Of tlnr 1.5 photomicrographs u u l I 4 oi I,crrrr qunlit?. n r p to be found i n another refcrrrrec. Chapter 10 cunrnin* s i photoncirrogrnphs ~ of some sulfa drug drrivativ,.s 1,ut otherwise is largely a discussion of how to make some crystalline organic derivatives on a micro slide and determine the melting point, rather than a discussion of the use of the mioroscope. Part 11 (90 pages) gives directions for performing 32 experiments which parallel the previous material. As there are no cross references (other than by chapter), much page turning is required to fit the two parts together. The first 12 experiments on the use and adjustment of the ordinary mierascope are excellent and should precede the usual laboratory work of biology students as well as chemists interested in microsoapy. Experiment 16 on Refmctive Index explains briefly the determination of the refractive index of isotropic (cubic ~ystem)materials only, and then discusses tho use of the microscope as a refractometer for ~~~
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liquids. The great usefulness of the Kofler hot stage for the determination of melting points under the microscope is given in Experiment 18. Experiment 19 on Polarired Light omits much and has the wrong emphasis; for instance, a half-page discussion of the "selenite" plate does not mention the sign of elongation or its use with interference figures. I t is the polarizing part of the polarizing microscope which is most useful to chemists, in the reviewer's opinion. The remaining experiments consist of selected inorganic ion identifications and some micromanipulations of s few organic derivatives usually ending with a meltingpoint determination! The book ends with a good six-page "condensed bibliography" of 31 books and 84 papers. However, some statement of the relative difficulty and usefulness of each, with a recommended order of study, would have improved its self-helpfulness. The chapters and experiments on the general use of the microscope will be valuable to the beginner and the others will suggest some chemical uses. The book is too verbose in pasts, and much valuable materid has been omitted. Ae there are several excellent reference books on the subject, in the opinion of the reviewer this is not the introductory book which is needed. H. COURTNEY BENEDICT
POLYSACCHARIDE CHEMISTRY Roy L. Whistler and Charles L. Smart, Department of Agricultural Chemistry, Purdue University. Academic Press, Inc., New York, 1953. xv 493 pp. Illustrated. 16 X 23.5 cm. $10.80.
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CARBOHYDRATE chemistry, particularly the chemistry of the polysaceharides, has been making such rapid progress in recent years that the average chemist whose chief interests lie in other directions has found it nearly impossible to keep abreast of di% coveries. Various review monographs have summarized very well different sectors of the advancing front, hut a book presenting the over-all picture was badly needed. The subject of this review goes a long way toward tilling that need. The authors begin with a discussion of the occurrence, nomenclature, and classification of polysaccharides which is the best this reviewer has found anywhere. Various tables are included, illustrating the remarkable and even amazing variety of ways in which Nature combines monosaccharide units to farm polyaacoharides. A second general chapter is devoted to methods used in the general characterization and proof of structure of polysacoharides. Here again the authors have rendered a valuable service in bringing together and explaining with great clarity principles and techniques, a knowledge of which has been too often assumed in other similar discussions. Here are explained the new techniques which are of such great utility in proving the structure of compounds which s. few years ago would have been considered unsolvable. The remainder of the hook is devoted to chapters on various types of polysaccharides. These 33 chapters cover all types of polysaccharide material with known or partially known structures and include such titles as Cellulose, Hemieellulose, Xylan, Mannan, Pectic Substances, Galactans, Starches, Tragacanth, Alginic Acid, Pneumococcal Polysaccharides, Dextrans, Chitin, Blood Group Polysaccharides, and Glycogens. Some of these
