December 19, 1907 J 



NA TURE 



147 



lar.cre proportion of the hundred thousand compounds 

 which organic chemistry is said to include. He 

 might, after a firm foundation had been laid, study 

 with advantage only those special subjects which 

 come within his sphere of interest. He cannot very 

 well know how to select these for himself, and Prof. 

 Bunge has therefore attempted to do it for him. 



On the whole, Prof. Bunge has been very success- 

 ful in the choice and arrangement of his materials, 

 and has produced an eminently readable book. But 

 the task cannot have been an easy one. In a small 

 volume of 250 pages, which is assumed to start with 

 the rudiments and finishes with such complex vital 

 products as the purines, the proteins, and the alka- 

 loids, there is a danger that the treatment may be 

 diffuse and superficial. But though this is certainly 

 not the case, it must be confessed that some prelim- 

 inary knowledge of analysis, molecuiar-weight 

 determinations, and especially about methods ot 

 studying structure, is desirable, if not indeed 

 necessary, if the subject is to be understood. In 

 support of this it may be pointed out that the struc- 

 tural formula of oxalic acid is given on p. 2, of 

 glyceric aldehyde and dioxyacetone on p. 5, and of 

 hippuric acid on p. 8, without any previous reference 

 to Kekule's structural laws. But this appears to be 

 the only serious defect, and one which the student 

 can easily remedy by a little preliminary study. 



The chapters are written in a manner well cal- 

 culated to stimulate the reader; indeed, no organic 

 text-book within the writer's knowledge is so full of 

 human interest. The following few errors have been 

 noted : — Chlorine does not convert aldehyde into 

 chloral, but mainly into butyl chloral (p. 50). It is 

 not true that " no one has yet succeeded in obtain- 

 ing directl)- by .synthesis either a d- or a Z-compound " 

 (p. 7g). On the contrary, asymmetric synthesis is an 

 accomplished fact. A racemic compound and a mix- 

 ture of enantiomorphs are not synonymous, and the 

 difference is indicated by r and dl (p. 89). The author 

 refers to the separation of synthetic tartaric acid into 

 its d- and Z-components by Jungfleisch as causing a 

 great sensation, " for up to that time many chemists 

 thought that optically active compounds could only 

 be formed by the living cell " (p. 89). There must 

 surely be some confusion here, for did not Pasteur 

 resolve racemic acid? Pasteur, it is true, considered 

 asymmetric synthesis, or the formation of one enan- 

 tiomorph without the other, as a peculiar property of 

 living matter, but that is another thing altogether. 

 Finally, on p. 147 occurs the old story of Wohler's 

 discovery of artificial urea in 1828, a date which 

 tradition and the text-books have fixed upon as that 

 of a two-fold event — the first organic synthesis and 

 th? downfall of the vital-force theory. In reality it 

 wa?. neither the one nor the other, and perhaps the 

 following observations may help to put the matter in 

 a clear light. 



The preparation of natural products in the 

 laboratory began before Wohler was born, for in 

 1776 -Scheele obtained oxalic acid bv oxidising 

 sugar. Doebereiner's preparation of formic acid 

 from tartaric acid in 1S22, and Hennel's synthesis 

 of alcohol from olefiant gas were both prior to 

 NO. 1990, VOL. 77] 



Wohler's discovery. That Doebereiner's discovery 

 received contemporary recognition is evident from 

 Berzelius's reference to it in the Jahresbericlit for 

 1823. " Doebereiner," he says, "has made the re- 

 markable discovery that formic acid may be produced 

 artificially." Now Liebig, in his treatise of 1840, 

 falls into a curious error, w-hich may lie at the bottom 

 of the text-book myth. In reference to formic acid 

 he writes, " Doebereiner was the first who prepared 

 it bv chemical means," whilst in another place he 

 says, " Woehler found a way of obtaining urea arti- 

 ficially, and it was the first substance formed in the 

 animal-life process which had been successfully repro- 

 duced by chemical means." Now formic acid is as 

 much a product of the animal-life process as urea, 

 and no real distinction can be drawn between them. 



It is clear, therefore, on Liebig's own showing, that 

 of the two artificial products, Doebereiner's has the 

 prior claim. How little Wohler's discovery served to 

 remove the belief in a vital force is very clearly indi- 

 cated in Gerhardt's " Precis de Chiniie Organique," 

 published in 1844. 



" A number of animal and vcget.-ible substances 

 have been reproduced by acting with oxygenating 

 agents on more highly carbonised compounds . . . 

 thus, the chemist has followed a path entirely opposed 

 to that pursued bv vegetable life . . . one need not 

 therefore feel astonished that he has not yet pro- 

 duced cerebral matter, nor the constituents of the 

 blood, nor equally complex substances." 



Thus the vital-force theory did not suddenly col- 

 lapse, as generally stated; on the contrary, it died a 

 slow and lingering death. We may, indeed, ask, is 

 it quite dead vet? For to quote the words of an 

 authoritative contemporary writer, " the testimony of 

 pure chemistry cannot as it at present stands be 

 legitimately interpreted into a direct negation of 

 vitalism in any form." 



There onlv remains to add a reference to the work 

 of the translator. Dr. Plimmer has not only rendered 

 the German into excellent English, but has added 

 verv considerablv to the text. J. B. C. 



OUR BOOK SHELF. 



(i) Some Nature Biogrnpliies : Plant, Insect, Marine, 



Mineral. By J. J. Ward. Pp. xvii + 307 ; illustrated. 



(London : John Lane, 1908.) Price 55. net. 

 (2) The Fairyland of Living Things. By R. Kearton. 



Pp. viii+'iSi; illustrated. (London: Cassell and 



Co., Ltd., 1907.) Price 3^. 6d. 

 (i) Mr. Ward's little work, which consists of a 

 series of articles originally published in the Strand, 

 Pall Mall, English Illustrated, and other maga- 

 zines and periodicals, may be regarded as a kind 

 of kinematograph in book form, and may be unre- 

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 the main based on actual personal observation, and 

 that, too, of a kind which demands constant attention 

 and the expenditure of no inconsiderable amount of 

 time. In his preface the author very modestly sug- 

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 to this credit, so far as our information goes, he is 

 fullv entitled. Nothing in nature-photography can, 

 indeed, be more interesting than his pictures of the 

 sequence of events which herald the complete liber- 

 ation of the butterflv or the moth from its chrysalis, 



