5o^ 



NA TURE 



[September 22, 1904 



Though M. Cels has devoted so large a part of his 

 work to the logical methods of anthropology, he tells 

 us little or nothing of the immense advance that has 

 been made in recent years in anthropometrics. No 

 science makes much progress until precise measure- 

 ment is applied to the characters the distribution and 

 correlations of which are to be ascertained. Measure- 

 ment has been applied to the body of man for more 

 than fifty years, but only within the last few years 

 has a statistical method been devised which enables 

 us to give the true interpretation of the vast amount 

 of anthropometric statistics that has been accumulated. 

 But the work of Galton and Karl Pearson receives no 

 notice from M. Cels in his work on the science of 

 man and anthropological method; we are referred 

 rather to the works, published fifty or more years ago, 

 of Cuvier, Krause, and Saint-Hilaire, whose ideas on 

 co-relation were mere shadows of the precise know- 

 ledge we now possess. 



As a highly abstract and suggestive exposition of 

 the nature and scope of anthropology, the book de- 

 serves a place in the library of the anthropologist. 



J. Gray. 



PROGRESS IN THE CHEMISTRY OF FATS. 

 Chemical Technology and Analysis of Oils, Fats, and 



Waxes. By Dr. J. Lewkowitsch, M.A., F.I.C. 



Third edition, re-written and enlarged. Two vols. 



Pp. xxviii+iiS2. (London: Macmillan and Co., 



Ltd., 1904.) Price 36s. net. 

 T N this, the third edition of Dr. Lewkowitsch 's well 

 i known work, there is naturally much that was not 

 included in the former issues. And since the second 

 edition was itself a somewhat bulky tome of more than 

 eight hundred pages, the author has wisely divided 

 the present work into two volumes, corresponding 

 broadly to the analytical and technological branches 

 into which his subject resolves itself. 



Briefly, the first volume deals with general principles, 

 the second with individual products. In the earlier 

 chapters there is a discussion of the theory of saponifi- 

 cation, and a description of the glycerides, esters, 

 alcohols, and acids which form the proximate con- 

 stituents of oils, fats, and waxes ; the rest of the first 

 volume is mainly devoted to an account of the chief 

 physical and chemical methods now employed in the 

 examination of these substances. In the second 

 volume, after a short generalised description of their 

 commercial methods of preparation, the individual oils, 

 fats, and waxes are dealt with. Under each article 

 are given its source, characteristic features, physical 

 and chemical constants, and such miscellaneous in- 

 formation as the technical uses of the product and the 

 nature of its probable adulterants. Finally, the last 

 two chapters embody an account of modern manu- 

 facturing processes employed in the various industries 

 —soap, candle, rubber, glycerol, and so on— for which 

 the raw materials are furnished by oils and fats. 



To specialists, the foregoing summary will show the 



present arrangement of what is now the standard 



English book of reference on the subject. To chemists 



who have not followed the progress of the chemistry 



NO. 182 1, VOL. 70] 



of the glycerides very closely it may be useful to indicate 

 a few of the more recent developments which, among 

 many others. Dr. Lewkowitsch has described or 

 referred to in the book under review. 



Looking back over the work of the last few years, 

 what strikes one as being the most notable advance 

 in the chemistry of fats is the recognition of mixed 

 glycerides as frequent if not normal constituents of 

 fats and oils. Since the days of Chevreul, until quite 

 recently, these latter bodies have been almost 

 universally regarded as mixtures of simple triglycerides- 

 — usually triolein, tripalmitin, and tristearin. True, 

 evidence was adduced more than a quarter of a century 

 ago, on the one hand by Bell and Lewin, and on the 

 other by Blyth and Robertson, which pointed to the 

 fact that butter-fat contained a mixed glyceride, 

 oleopalmitobutyrin. But, probably owing to the 

 difficulty of isolating and definitely proving the identity 

 of such compounds, the observation long remained 

 almost unnoticed. During the last few years, how- 

 ever, the mixed glyceride oleodistearin has been 

 obtained by Heise from kokum butter, stearopalmitin 

 by Hansen from tallow, oleopalmitostearin and oleo- 

 dipalmitin by Klimont from cocoa-butter, and daturo- 

 distearin by Kreis and Hafner from lard. This does 

 not exhaust the list; and, indeed, the probability is 

 that on further investigation mi.xed triglycerides will 

 be found in most oils and fats. Several have also been 

 synthesised, chiefly by Guth ; thus two isomers of 

 stearodipalmitin have been prepared, the a variety from 

 o-monostearin and palmitic acid, and the 3 form from 

 a-dipalmitin and stearic acid. 



Another point of interest is the frequent, and perhaps 

 general, occurrence of fat-splitting enzymes such as 

 steapsin in both vegetable and animal oils and fats. 

 The author is strongly in favour of the view that the 

 rancidity of fats is due initially to hydrolysis of the 

 glycerides by these ferments. To this, however, one 

 possible objection suggests itself. Enzymes are usually 

 destroyed at moderately high temperatures — e.g. 

 maltase at So°. Is there any evidence to show that 

 lard or tallow prepared at steam-heat, or any fat 

 specially raised to a temperature of, say, 95° to 100°, 

 does not turn rancid? If it does not, so much the 

 better for the enzyme theory of rancidity. If it does, 

 one would still like to have other evidence that the 

 enzymes present are capable of withstanding these 

 higher temperatures. 



As regards the analytical chemistry of fats, the most 

 important among recent advances is undoubtedly 

 Hehner and Mitchell's method of determining stearic 

 acid. It is not an ideal process, and shows at least 

 one anomaly; but it does place in the chemist's 

 hands a valuable and long-wanted means of estimating, 

 with reasonable accuracy and expedition, the propor- 

 tion of one of the most frequent constituents of natural 

 glycerides. To the same investigators, following 

 Hazura, is also due the working out of what promises 

 to be a very useful aid to the study of unsaturated 

 glycerides, namely, the quantitative determination of 

 their hexabromide derivatives. Of new methods 

 having an immediate value to the practising analyst 

 there may be mentioned Bomer's phytosterol test for 

 vegetable oils, and Polenske's process for detecting 



