NATURE 



609 



THURSDAY, OCTOBER 17, 1907. 



STF-REOCHEUISTRY. 

 Stereochemistry. By Dr. A. W. Stewart. Pp. xx + 

 5S3. (Tcxt-BooUs of Physical Chemistry. Edited 

 by Sir William Ramsay, K.C.B., F.K.S.) (Lon- 

 don : Longmans, Green, and Co., n)Ci7.| Price 

 lux. 6rf. 



THIS book is practically a complete and in many 

 cases a detailed account of the subject of stereo 

 or space chemistry since the foundations of this ex- 

 ceedingly fruitful branch of chemical science were laid 

 by Pasteur and Wislicenus. It is not an historical 

 summary, but a carefully thought out treatise, and 

 one which chemists who have to lecture or teach the 

 subject will find of the greatest use. 



The book commences with a short historical intro- 

 duction. Part i. deals with optical activity, the first 

 section describing the asymmetry of the carbon atom. 

 The author's idea of explaining the effect of polaris- 

 ation on light by means of a paper-knife and two 

 books is distinctly good. The next chapter deals with 

 inactiv-e compounds, and from this we are led up to 

 the active compounds and the determination of con- 

 figuration. 



Chapter viii., on " other active elements," is a 

 review of the work done upon nitrogen compounds, 

 and also deals with the isolation of active compounds 

 of sulphur, selenium, and tin by Pope and his co- 

 adjutors. The first part of the chapter is a survey 

 of cases in which nitrogen is known to show 

 isomerism; the second part is a consideration of the 

 various theoretical explanations put forward upon the 

 configuration of nitrogen compounds. This complex 

 part of the subject would perhaps have been more 

 easy to follow if the author had been able to devote 

 a little more space to the consideration of these 

 theories, but as the references are ample and the book 

 is by no means short, even as it is. Dr. .Stewart must 

 be left as the best judge of how much space to devote 

 to each portion of the work. As the author himself 

 says in his preface, stereochemistry is much easier 

 to follow if one has a set of models to work with. 

 It is, in fact, very difficult to study the subject from 

 a book alone, and in .'\ppendix B directions for the 

 construction of stereochemical models are given, one 

 of the simplest methods for making tetrahedra being 

 to cut them out of hard yellow soap, needles being 

 used for bonds. 



Steric hindrance is a subject which is very much 

 to the fore at the present time, and one rarely visits 

 a meeting of the Chemical Society without hearing it 

 mentioned. For this reason the chapter on steric 

 hindrance in this book is of particular interest. To a 

 certain extent also interest is added because the 

 author, in, connection with his work with Baly upon 

 absorption spectra, has come across facts which in 

 the opinion of the authors are a contradiction to the 

 theory of steric hindrance, -Stewart and Baly holding 

 that in the' case of the carbonyl group the reactivity 

 is not inherent in the group itself, but depends upon 

 the " nascency " of the radical, this " nascency " 

 NO. 1 98 I, VOL. 76] 



being governed by the action of the adjacent groups 

 upon the carbonyl radical. Could not some rather 

 more euphonious name be chosen for the activity of 

 the group than " nascency "? One can perhaps 

 hardly talk about the atomic character of a group ; 

 would not activity itself do? It is not unusual to 

 speak of hydrogen, at the moment of its liberation, 

 being in the active form, but one never talks of the 

 " nascency " of hydrogen. Or one might borrow an 

 electrochemical term, and speak of the potential of 

 the group. Thus the potential of hydrogen is high 

 or low, depending upon the surface and character 

 of the electrode from which it is liberated^ and the 

 tension or potential of the carbonyl group might be 

 high or low, depending upon the character of the 

 adjacent groups. 



Appendix A deals with the relations of stereo- 

 chemistry to physiology. That the configuration of 

 the groups should affect the physiological action is cer- 

 tainly interesting. Thus when given to rabbits in 

 various ways it was found that in the case of the 

 three arabonic acids more of the laevo- than of the 

 dextro-variety was acted upon, and in the case of the 

 mannoses the dextro-variety appears to be best suited 

 for nourishment. The taste, at any rate to some 

 extent, depends upon the stereoisomeric form ; thus 

 in the case of glutaminic acid the dcxtro-form is 

 sweet, but the laevo-form is tasteless. Furthermore, 

 the toxic action in some cases varies considerably with 

 the different isomeric modifications. For example, 

 ;-hyoscyamine is almost twice as active in its effects 

 upon the pupil nerve-endings as d/-hyoscyamine. This 

 branch of the subject is of great interest, and doubt- 

 less the gathering together of these facts will serve 

 to stimulate investigation in this valuable practical 

 part of the subject. 



The illustrations are good, some of the half-tone 

 reproductions of models being excellent, and the book 

 itself is well got up. It is decidedly one of the most 

 useful of the series, and Dr. Stewart is to be con- 

 gratulated upon the completion of a very painstaking 

 work. F. M. P- 



ORIENTAL PLAGUE. 

 Studies in the Bacteriology and Etiology of Oriental 

 Plague. By Dr. E. Klein, F.R.S. Pp. xv + 301. 

 (London: Macmillan and Co., Ltd., 1906.) Price 

 I2S. net. 



THE appearance of this book at the present time 

 is opportune, for plague is ravaging our Indian 

 Empire, some 900,000 deaths having been recorded 

 there from January i to May 31 this year. The work 

 is based on Dr. Klein's large experience of the 

 bacteriological examination of cases which clinically 

 and epidemiologically were under suspicion of being 

 plague. Many epizootics among rats on shipboard 

 were also investigated by Dr. Klein, and the results 

 of his examinations are included. The data so ob- 

 tained, and published in many scattered papers, arc 

 thus brought into a convenient form for reference. 



In chapter i. a good account is given of the histology 

 of plague lesions and of the distribution of the plague 



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