484. 



SCIENCE 



[X. S. Vol. XXX. No. 771 



■expected to construct correct crystal drawings 

 if the text to which he naturally turns for 

 comparison is lacking in this? If some of 

 the figures had been drawn on a larger scale 

 and then reduced these errors would have been 

 to some extent eliminated. 



Fig. 3, p. 51, is given as a combination of 

 the plus and minus diploids. What the author 

 has really drawn is a left gyroid (pentagonal 

 icositetrahedron). Diploids are symmetrical 

 to three principal planes of symmmetry where- 

 as gyroids lack these elements. The figure of 

 chrysolite on page 105 is very poor, as the 

 lines of intersection of the bipyramid (111) 

 with both the macro (101) and the brachy 

 (021) domes are incorrect. 



The method of determining the position of 

 the axes of the triclinic system is an ingenious 

 one, being a graphic solution of a spherical 

 triangle when three sides are given. The last 

 chapter on twinned crystals is very instructive, 

 as the author gives numerous practical sug- 

 gestions which are of great service in the con- 

 struction of these diificult forms. 



The work as a whole is a marked contribu- 

 tion to the science of crystal drawing and is a 

 valuable reference book in spite of the errors 

 referred to above. Walter F. Hunt 



mineealogical laboratory, 

 University of Michigan 



The Chemical Constitution of the Proteins. 

 E. H. Aders Plimmer, D.Sc, Assistant Pro- 

 fessor of Physiological Chemistry in, and 

 Pellow of University College, London. In 

 two parts. Part I. London and New York, 

 Longmans, Green and Co. 1908. 

 This volume forms one of a series of mono- 

 graphs appearing from time to time, covering 

 selected topics in biological chemistry and 

 written by investigators in the subjects dealt 

 with. The contents are divided into the 

 chemical composition of the protein molecule 

 and the chemical constitution of its units, or 

 the discovery and synthesis of the amino 

 acids. The introduction gives a list of the 

 proteins according to the British classification 

 followed by a complete list, with their struc- 

 tural formulae, of the various protein nuclei 



thus far discovered. The first section con- 

 sists of a short survey of the methods em- 

 ployed for the decomposition of the proteins; 

 this is succeeded by a detailed account of the 

 method of isolation and estimation of the 

 monamino and diamino acids, the former fol- 

 lowing the ester method of Fischer with some 

 variations suggested by Levene and the latter 

 employing the method described by Kossel. 

 The results of the analyses of the various pro- 

 teins made by the several authors are given in 

 tabular form. The collection of this data and 

 presentation in compact form forms one of the 

 chief advantages of the book. The second 

 section is but a compilation of data relating 

 to the many protein nuclei covering the date 

 of their discovery, determination of their con- 

 stitution, and methods of preparations by syn- 

 thesis. Some of these details have been tab- 

 ulated at the end with the specific rotatory 

 power of the natural and synthetic amino 

 acids, mentioning by whom the observations 

 were made. The book closes with a complete 

 bibliography including about 500 titles and 

 index. 



The function of such a compilation must 

 naturally be somewhat circumscribed. It can 

 only be of value as a bibliography mainly and 

 as a source of supply of somewhat complete 

 data for the busy teacher who would utilize 

 this book rather than investigate the original 

 communications. The synthetic reactions are 

 described by equations with structural for- 

 mulae which are undoubtedly a valuable aid to 

 their proper understanding and elucidation. 

 The contents are too detailed for the student; 

 investigators and teachers would probably pre- 

 fer to consult the original articles. 



Practical Physiological Chemistry. A Book 

 Designed for Use in Courses in Practical 

 Physiological Chemistry in Schools of 

 Medicine and of Science. By Phillip B. 

 Hawk, M.S., Ph.D., Professor of Physiolog- 

 ical Chemistry in the University of Illinois. 

 Second edition, revised and enlarged. Phil- 

 adelphia, P. Blakiston's Son & Co. 1909. 

 In the revision of the book the author has 



placed at the beginning a new chapter of 



