May 19, 1910J 



NATURE 



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conceived under the limitations of ordinary cogni- 

 tion. 



The concluding' chapter dwells on the relative and 

 symbolic nature of science and its subordination to 

 life; on the insufficiency of human life in itself as an 

 end ; on the ideal of duty which summons us beyond 

 the specifically human to a noble struggle and a great 

 hope, an ideal which implies faith and love, which 

 demands a God, and a God with whom we can be in 

 communion. It is in the '" living reason " interpreted 

 in the light of duty that science, without which we 

 cannot live, and religion, without which we do not 

 wish to live, find their reconciliation. It must be 

 admitted that this chapter, fine as it is, could not 

 endure the rigorous logic which M. Boutroux has 

 applied to others. His duty is formal, and though a 

 formal notion ma);, as he says, be efficacious, that 

 concrete efficacy is psychological ; we are no nearer 

 a logical synthesis than we were, say, with the 

 notion of concrete activity. But the failure of this 

 effort at construction does not diminish the success 

 of the book in its main intejition of critical estima- 

 tion. ?*I. Boutroux is, like most French writers, a 

 master in exposition ; he excels especially in revealing 

 that natural logic by which a biassed view tends to 

 correct itself, an excellence which indicates both the 

 generous critic and the trained philosopher. Probably 

 no bock has been written on the subject which will 

 so well repay the student's attention. 



THE CHEMISTRY OF THE SUGARS. 

 The Simple Carbohydrates and the Glucosides. By 

 Dr. E. Frankland Armstrong. Pp. ix+112. (Lon- 

 don : Longmans, Green and Co., 1910.) Price 

 35. 6s. net. 



CHEMISTS as well as physiologists will welcome 

 the latest addition to the monographs on bio- 

 chemistry, for there is no other branch of the subject 

 which has afforded so many brilliant examples of 

 successful synthesis or shed so much light on the intri- 

 cate problems of enzyme action. 



The editors have been fortunate in securing the 

 collaboration of Dr. E. F. Armstrong, who has made 

 a special study of the chemistry of the carbohydrates, 

 and writes with an intimate practical knowledge of 

 his theme. .\t the first glance through the pages of 

 this volume one receives the impression that the author 

 starts on too high a plane, and assumes an acquaint- 

 ance with the methods and problems of stereochemistry 

 which the biochemical reader may not possess ; but 

 one realises on reflection that if he has to compress 

 into ninety-two pages the substance of a subject 

 upon which volumes have been written, he has deter- 

 mined wisely in concentrating, into this restricted 

 space those modern developments of sugar chemistry 

 which are of special interest to the biologist, and in 

 leaving other things to take care of themselves. 



It is, no doubt, for this reason that the main atten- 

 tion is directed to the natural sugars and glucosides, 

 and that the artificial products are only touched upon 

 where questions of a more general nature are con- 

 cerned. 



The first two chapters are devoted to the structure 

 NO. 21 16. VOL. 8^1 



and properties of glucose, and are followed by one 

 describing the natural hexoses and pentoses, whilst 

 the fourth contains a description of the disaccharides. 

 The succeeding two chapters contain an account of 

 problems with which the author is more closely identi- 

 fied, apd furnish much the most interesting reading. 

 In the first of these the subject of configuration in 

 its relation to enzyme action is discussed, and includes 

 the selective action of maltase and emulsin on the 

 glucosides to which Fischer first directed attention, and 

 the selective oxidation of alcohols and sugars by the 

 sorbose bacterium described by Bertrand. 



L'nder " Hydrolysis and Synthesis," in which refer- 

 ence is made to the rate of hydrolysis of the disacchar- 

 ides bv acids and enzymes, the author discusses his 

 stereochemical hypothesis, based on a series of inter- 

 esting numerical data. Such a hypothesis, which 

 mav be tested experimentally, can only enlarge our 

 outlook, and the same may be said of the mechanical 

 similes of templates (p. 71) and glove fingers (p. 58), 

 provided we regard the latter, as Fischer did his lock 

 and key, as similes only and nothing more. The 

 writer would, however, like to raise a mild protest 

 against a fusion of the two ideas which the author 

 makes use of in the formula on p. 58, where the 

 atoms of enzyme and substrate are represented as 

 interlocked, a theory which, on the one hand, can 

 never be tested experimentally, and, on the other, 

 can offer no advantage over the lock and key or 

 other mechanical simile. 



On the whole, the subject is well and clearly 

 written, and there is very little with which the critical 

 reader can find fault. Here and there certain passages 

 occur which might be improved by expansion or modi- 

 fication, and in this connection reference may be 

 made to the following paragraphs : — 



On p. 66 we are told that the difference in the 

 hydrolvtic behaviour of enz\-mes and acids is "due 

 mainly if not wholly (i) to the superior affinit}^ of 

 the enzjmes for the carbohydrates ; (2) to the very 

 different behaviour of the two classes of hydrolysts 

 toward water — which is a consequence of the colloid 

 nature of the one and the crystalloid nature of the 

 other." One would like to know more precisely how 

 the ■■ superior affinity" and "colloid nature" act in 

 favour of the enz\-me. 



On p. 70 the author refers to Fenton's reduction of 

 carbon dioxide to formaldehyde by magnesium as a 

 deeplv significant observation when considered in rela- 

 tion to Willstatter's discover}- that chlorophyll con- 

 tains magnesium. Are we to suppose that the mag- 

 nesium in chlorophyll plays the part of the free metal? 

 If not, what is the deep significance of the obser\-a- 

 tion? 



There is a slip on p. 59, where o-carbon atom should 

 be " first carbon atom," and on p. 68, where it is 

 stated that sorbose is derived from mannitol. Xylose 

 is not limited to straw, but is found in most kinds of 

 wood (p. 37). In the separate description of the 

 disaccharides, for some reason not given, three mem- 

 bers in table viii. are omitted. On the first page of 

 the introduction the author says, '"The members of the 

 sugar group are usually distinguished by names hav- 



