April 25, 1902.] 



SCIENCE. 



661 



the same conditions miglit inhibit the action 

 of the real lines of propagation, whatever they 

 are. 



Further investigation is demanded for the 

 elucidation of this interesting problem. 



C. R. Barnes. 



The University of Chicago. 



Boscoe-Schorlemmer's Ausfuhrliches Lehrhuch 

 der Chemie. Von Jul. Wilh. Beuhl, Pro- 

 fessor an der Universitat Heidelberg. 

 Neunter Band, Die Eohlenwasserstoffe und 

 ihre Derivate oder organische Chemie; 

 Siebenter Theil. Bearbeitet in gemeinschaft 

 mit Edward Hjelt und Ossian Aschan, 

 Professoren an der Universitat Helsingfors, 

 O. CoHNHEiM, O. Emmeeling und E. 

 Vahlen, Privatdocenten an der Universi- 

 taten Heidelberg, Berlin und Halle, A. S. 

 Braunschweig, Druck und Verlag von Fried- 

 rich Viewig und Sohn. 1901. 

 The present volume, being the seventh vol- 

 ume of 'Organic Chemistry,' and the ninth 

 volume of Roscoe-Schorlemmer's 'Ausfiirh- 

 liches Lehrhuch der Chemie,' constitutes the 

 closing volume of this important work. It 

 deals with three distinct topics of physiological 

 chemistry, viz., the 'Chemistry of the Albumi- 

 nous Bodies and the Constituents of Bile,' 

 written by Dr. 0. Cohnheim, of Heidelberg; 

 'Enzymes,' written by Dr. O. Emmerling, of 

 Charlottenburg ; 'Ptomaines and Toxines,' 

 written by Dr. E. Vahlen, of Halle. 



The section on proteids covers 331 pages, 

 and is a well-presented statement of facts and 

 theories bearing on the various classes of pro- 

 teids of physiological interest. It is thoroughly 

 up-to-date, and makes a valuable addition to 

 the list of handbooks which aim to present a 

 systematic account of the chemical nature of 

 this important group of proximate principles. 

 The section on 'Enzymes' is divided into 

 eight chapters, dealing respectively with 

 enzjrmes which have a splitting action on 

 monosaccharides, disaccharides, polysacchar- 

 ides, glucosides, glycerides, etc., while other 

 chapters or subsections deal with oxidizing and 

 reducing enzymes, clotting enzymes, proteo- 

 lytic enzymes of both animal and vegetable 

 origin, amide-splitting enzymes, etc. 



The last section of the book, by Dr. Vahlen, 

 deals with ptomaines and toxines, and consti- 

 tutes an interesting chapter on the chemistry 

 of these products of bacterial life and grovTth. 



The volume, as a whole, reflects great credit 

 upon the several authors, and will undoubtedly 

 prove of great service as a reference handbook 

 for physiological chemists. 



E. H. Chittenden. 



History of Geology and Paleontology to the 

 End of the Nineteenth Century. By Karl 

 Alfred von Zittel. Walter Scott. 1901. 

 16mo. Pp. xiii -1-562. 



This work is timely. Lyell's synopsis of 

 views and opinions comes down to barely 

 seventy-five years ago; Whewell's chapters on 

 geology, though nominally covering the period 

 down to 1855, are unsatisfactory at best; 

 d'Archiac's work, too voluminous for the ordi- 

 nary student, ends with 1859 ; while nearly all 

 of the other so-called histories are histories, 

 not of the science as a whole, but of separate 

 branches surrounded by a framework of chap- 

 ters upon other branches. The preparation of 

 a history of geology and paleontology is no 

 longer a simple task, and before many years 

 it will be an almost impossible task, for the 

 several lines of investigation now embraced 

 under the general title of geology are fast 

 becoming wholly independent sciences. One 

 must welcome this history, covering the whole 

 period to the end of the nineteenth century, 

 prepared by one who first attained eminence in 

 geology and afterwards turned with equal suc- 

 cess to paleontology. 



The introduction of 153 pages reviews the 

 steps by which the science advanced. The 

 synopsis of opinions held by ancient writers is 

 just, with full recognition of their merits, yet 

 showing their defects in such manner that no 

 excuse remains for regarding the Greek phi- 

 losophers as gifted beyond modern students. 

 One hundred pages are devoted to the 'heroic 

 age,' 1790 to 1820, in which one finds appre- 

 ciative discussions of the doctrines presented 

 by Werner, Hutton, Playfair, Humboldt, Kant 

 and the rest, which, too often, have received 

 either unstinted praise or unstinted censure. 



