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NEW BOOKS
prove a correspondingly useful reference work. As an interesting commentary on the importance attached to these data, we note that over 400 papers are cited regarding the physical constants of the parent aromatic, benzene. We cannot suppress a note of regret for the high price of this volume. BRYCEL. CRAWFORD, JR.
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Physical Chemistry f o r Premedical Students. By JOHNPAGE AMSDEN. x 298 pp.; 54 fig. New York: McGraw-Hill Book Company, Inc., 1946. Price: $3.50. This slim volume is designed by its author to treat those portions of physical chemistry which are of value to the premedical student; i t includes, after the more or less usual chapters on dimensions and units, gases, and liquids, chapters on solutions, properties of solutions, both non-electrolytic and electrolytic, chemical equilibrium, hydronium ion (including a very elementary treatment of galvanic cells), oxidation and reduction, reaction rates, and eo oids, including some membrane phenomena. We believe that Prof. Amsden’s selection of topics to include in his text is quite good, wisely omitting all material with which the medical student will not come into contact. The various formulas which are developed are well illustrated by numerical examples, rather clearly worked out; each chapter has a t its conclusion a number of problems on which the student can exercise his understanding. We should not favor quite as much strictly physiological material as Prof. Amsden has included in, for example, the last few pages having t o do with osmotic pressure, or in the last page or two of the chapter on colloids; but this is a matter of taste, and is certainly not too serious. We feel we must vigorously criticize the oversimplified derivations given for many of the important relationships in this text. We agree thoroughly with the position Prof. Amsden takes in his preface, that “for the student to appreciate fully the possibilities and limitations of the equations of physical chemistry i t is essential that he be familiar with their derivations.” We also agree with Prof. Amsden that simplified derivations may be best for premedical students, whose mathematical background is never too sure; but we fear that Prof. Amsden’s derivations are simplified to the point of inaccuracy in many cases, and in some cases to the point where they smack of an intellectual swindle. Thus the derivation given for the osmotic-pressure relationship on pages 91-93 would lead the student to believe that the equation arrived a t (No. 37) is exact for the approximations of a perfect gas for the vapor and of a perfect solution; as a matter of fact, the equation is not exact under these circumstances, and we believe that the premedical student can profit from a knowledge of the more exact osmotic-pressure relationship. Again, the derivation of the Nernst equation given on pages 186-189 caused us definitely to squirm. Another criticism we must make, again arising from our dissatisfaction with Prof. Amsden’s simplifications, is of the section on oxidation and reduction energy changes, given on page 226 and following. The brief discussion of calorimetric and potentiometric energy determinations is most likely to lead the student to believe that the heat of a reaction and its free energy are equivalent (though of course this statement is not made in just these terms). We do not believe i t wise to leave such a misconception in a student’s mind. Perhaps this is a difference in pedagogical viewpoint; Prof. Amsden may feel that it is better to give his students a simple half-truth which they can understand, than to risk confusing their minds with a distinction that they will, probably, never encounter in medical work. We do not; we would prefer that students get a misty glimpse of a difficult truth rather than a clear understanding of a simple falsehood. To teachers who feel that our viewpoint is too meticulous, and who agree with Prof. Amsden that oversimplification is justified in persuading premedical students that they know something of physical chemistry, his book should be worthy of consideration. BRYCEL. CRAWFORD, JR.
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