591.3 4" 



VI. 



Oscar Hertwig on Mechanics and Biology.' 



THE first volume of Professor Hertwig's " Biological Problems of 

 Today," that dealing with Preformation and Epigenesis, was 

 summarised in these pages by its subsequent translator, Mr. P. 

 Chalmers Mitchell, in August, September, and October of 1894 

 (Natural Science, vol. v., pp. 132-134, 184-194, and 292-297). A 

 review of the English translation was published in our volume ix., 

 pp. 270-271. In the second volume, which has recently been issued, 

 Professor Hertwig has taken "Mechanics and Biology" as his theme, 

 and treats the relation between these two branches of science from a 

 very critical standpoint. The whole book is an energetic protest 

 against the tendency of a certain school of writers, among whom 

 Wilhelm Roux ranks as pre-eminent, to exalt mechanics as the science 

 •of the future, and to regard all biological, and especially embryological, 

 phenomena as the outcome of purely mechanical processes. 



The general question is discussed by Professor Hertwig in his 

 introductory chapter, and the rest of the book deals more particularly 

 with various attempts to elevate the so-called " mechanics of 

 development " into a new and separate science. The goal to which 

 this science of the future tends, and its methods, are discussed under 

 separate headings, while a lengthy appendix, occupying nearly half the 

 book, is devoted to a more detailed consideration of the laws of develop- 

 ment according to Roux, or the " causal morphology " for which he 

 claims such a high place. 



Professor Hertwig is doing good service in leading a crusade 

 against the over-glorification of mathematics, and the attempt to force 

 biology into posing as one of the exact sciences. Apart from questions 

 relating to pressures upon the skeleton and similar problems, 

 mechanics in the strict sense have comparatively little to do with 

 biology, and the introduction into zoological writings of words coined 

 for another branch of science, and bearing therein a different conno- 

 tation, can only lead to mystification. This is, however, an error only 

 too prevalent among modern scientific writers of all nations. Our 

 author draws attention to Roux's present use of the word " mechanics," 



1 Zeit-und Streit-fragen der Biologie. Heft. II., Mechanik und Biologie. 

 By Professor Dr. Oscar Hertwig. Svo. Pp. iv., 211. Jena: G. Fischer, 1897. 

 Price 4 marks. 



2 G 2 



