i 



Supplement to "'Nature" November 14, 1901. 



lication. The above example is typical of the treatment 

 throughout, and the student or worker may confidently 

 make use of any portion of the vast mass of information 

 crowded into every page as accurate and authoritative. 

 It is interesting to note also how among compounds of 

 industrial importance references to patents figure occa- 

 sionally in the literary notes. We have on former 

 occasions pointed out that discoveries of first-rate 

 scientific importance are often in the first place published 

 through the Patent Offices, owing to their being also of 

 commercial value. 



The larger portion of the eighth volume deals with the 

 vegetable alkaloids, and concerning this we have only to 

 refer our readers to the opinion expressed in the former 

 notice (NATURE, vol. l.xiii. p. 486, March 21, 1900). Dr. 

 Briihl states in the preface that this monograph was sent 

 to press in January 1900, and the printing concluded in 

 October of the same year. The volume contains in 

 addition a monograph on vegetable glucosides which 

 occupies 138 pages, sections on bitter compounds (non- 

 glucosidic) and natural organic colouring-matters, and 

 sections amounting to monographs on chlorophyll and 

 the compounds obtained from lichens. The concluding 

 section is devoted to the indifferent or neutral compounds 

 not previously considered. It will be only necessary to 

 indicate very briefly the contents of these sections. The 

 glucosides are classified according to the nature of the 

 complex associated with the carbohydrate residue such 

 as hydrocarbon glucosides (picrocrocin), glucosides of 

 benzophenols, of alcohols, of aldehydes, of acids, of oxy- 

 anthraquinone, of oxyflavone, &c., and those glucosides of 

 which the products of hydrolysis are at present imper- 

 fectly known. The neutral bitter principles comprise 

 compounds such as aloin, picrotoxin, podophyllotoxin, 

 cantharidin, &c. The natural colouring-matters are 

 classified as derivatives of pyrone, of benzophenone, of 

 hydrindene, of naphthalene and anthracene, &c. Not 

 the least interesting of this group of compounds are the 

 colouring-matters derived from insects, such as cochineal, 

 lac-dye and kermes, which are classified as hydrindene 

 derivatives. Our knowledge of these compounds has 

 made considerable progress of late years, as will be seen 

 on reading this connected account of the researches of 

 Lieberniann and his pupils on carminic acid. So also it 

 may be noted that our knowledge of the constitution of 

 the colouring-matters of logwood, Brazil wood and of 

 other familiar vegetable dye-stuffs has been much ad- 

 vanced by the work of W. H. Perkin, jun., and his col- 

 leagues. Should these ever (as is not at all improbable) 

 come Within the domain of accomplished syntheses, we 

 might see the last of the vegetable dyes replaced by the 

 products of chemical factories. 



The section on chlorophyll is quite remarkable for its 

 completeness, and will appeal not only to chemists, but 

 to physiological botanists and biologists generally. It 

 occupies more than seventy pages and comprises a biblio- 

 graphical list of no less than nine pages, giving full refer- 

 ences to all the papers and memoirs of any importance 

 that have been written on the chemistry of this subject, 

 the arrangement being chronological from the memoirs 

 of Senebier in 1782-178S down to the latest papers of 

 Marchlewski and Schunck in 1900. Under this section 

 NO. 1672, VOL. 65] 



there are comprised not only chlorophyll and its deriva- 

 tives, but the various yellow colouring-matters which 

 accompany chlorophyll and other related compounds 

 Equally remarkable as a revelation of progress is the 

 long list of lichen products, our knowledge of which has 

 been so largely extended of late years, chiefly through 

 the labours of Hesse and Zopf, who have won for them- 

 selves the foremost position as pioneers in this branch 

 of plant chemistry. Nearly 100 distinct compounds of 

 this group have now been isolated and analysed, and 

 considerable progress has been made towards establish- 

 ing the constitutional formulae of some of them. Vulpic 

 acid, which occurs in many lichens and which was first 

 isolated in 1831, was synthesised by Volhard in 1894. 



The prevailing impression left after looking through 

 the contents of this eighth volume is that its interest 

 will extend to a much wider circle of readers than those 

 who are likely to make use of it from the purely chemical 

 point of view. The immense number of natural products 

 — such as alkaloids, colouring-matters, neutral com- 

 pounds, chlorophyll, glucosides, lichen products, &c. — 

 described and discussed will make this instalment of the 

 new " Roscoe and Schorlemmer '' particularly valuable 

 to physiologists. In the words of Ur. Briihl, who in the 

 preface calls attention to the circumstance that the present 

 volutne contains a large amount of material which has 

 now in part undergone systematic chemical investigation 

 for the first time : — 



" VVenn dieses Material fiir den Chemiker mehr als 

 alle bisher behandelten Gruppen noch Unbekanntes en- 

 thiilt, so ist es fiir den Biologen nicht minder fragenreich 

 und von grosser Bedeutung. In dem rapiden Entwickel- 

 ungsgange der Naturwissenschaften niihert sich die 

 Chemie in neuester Zeit immer rascher den biologischen 

 Disciplinen, una eine zusammenfassende Bearbeitung 

 derjenigen Gegenstiinde, welche gegenwartig diese 

 Wissenszweige beschaftigen und mit der Chemie ver- 

 kniipfen, wird daher zweifellos Vielen willkommen sein. 

 Es ist in diesem Bande, mit besonderem Hinblick auf die 

 Interessen eines weiteren naturwissenschaftlichen Kreises, 

 zwar stets das Chemische als Hauptaufgabe behandelt, 

 indessen auch das Biologische so weit beriicksichtigt 

 worden, als dies in einem chemischen Lehrbuch thun- 

 lich erschien." 



One serious consideration arising from the publication 

 of the present work is that a standard treatise originally 

 planned and published in this country should now have 

 passed out of our hands. The reading public interested 

 in chemical literature cannot have been sufficiently 

 numerous to warrant the publication of a revised edition' 

 in English. On the other hand, we find German chemists 

 of the very highest repute willing to undertake the literary 

 labour and a German firm willing to incur the risk and 

 bear the expense of publication. The writer knows 

 nothing of the cost of printing and publishing in Germany, 

 but the price of the books is not less than that of the 

 original edition in this country (vol. viii., in paper 

 wrappers, is priced at 22 marks), so that it cannot be 

 urged that the German student gets his text-books 

 cheaper than the English student. The natural conclu- 

 sion would appear to be that a sufficiently large number 

 of readers in Germany can be depended upon to warrant 

 the risk of publication of the work in that language, and 

 this again raises the question whether the kind of scientific 



