344 



SCIENCE 



[N. S. Vol. XXX. No. 767 



his failure to notice any of the writings 

 of Joseph Le Conte who certainly was well 

 known to a wide circle of readers in this 

 subject. There was, of course, room for dif- 

 ference of opinion about the validity of re- 

 sults, for Dr. Le Conte's first papers were 

 evoked by what he considered to be mistakes 

 made by Claparede and Hehnholtz. Between 

 1868 and 1882 he published more than a dozen 

 papers on physiological optics in the American 

 Journal of Science; and the substance of these 

 was afterward incorporated in a volume on 

 " Sight," which passed through several edi- 

 tions. His acuteness as an observer was gen- 

 erally conceded, and the value of his work was 

 certainly greater than that of some whose work 

 had been done in Germany. He was not a 

 mechanical inventor, and no instruments are 

 ascribed to him. This fact may possibly ac- 

 count for failure to recognize his theoretic 

 work in a book on " Binokularen Instru- 

 mente," but in this book there is much inter- 

 esting reading on theoretic matters. 



Since 1890 von Rohr finds a renewal of in- 

 terest in binocular vision to have set in. For 

 this much credit is due to Dr. Abbe and the 

 school of scientific workers stimulated by him. 

 The binocular microscope had passed out of 

 favor, but between 1880 and 1895 Abbe pub- 

 lished a considerable number of papers on 

 binocular microscopes and telescopes, in 

 which he described improvements of such 

 marked value as to compel attention. Since 

 his death the work of development has been 

 continued by his successors, and to-day the 

 Optische Werkstatte at Jena constitute the 

 center from which most of the modern binocu- 

 lar instruments have been issued. Among the 

 most important of these are the Zeiss stereo- 

 binocular field glasses with Porro prisms, 

 which are now the standards of excellence in 

 this branch of applied optics. 



The third part of von Rohr's book is a sys- 

 tematic arrangement of its contents and a val- 

 uable index of the literature of the subject. 

 The care and thoroughness with which this 

 has been prepared is worthy of much praise; 

 indeed it is a model of its kind, and is signifi.- 

 cant of the dominant standards where optical 



literature is as completely methodized as me- 

 chanical work. W. LeC. Stevens 

 Washington and Lee Univebsity, 

 July 12, 1909 



Intracellular Enzymes — A Course of Lectures 

 Given in the Physiological Laboratory, Uni- 

 versity of London. By H. M. Vernon, 

 M.A., 1I.D., Fellow of Magdalen College, 

 and Lecturer on Physiology at Exeter and 

 Queen's Colleges, Oxford. London, John 

 Murray. 1908. Pp. xi + 240. Price 

 Ys. 6d. net. 



It is only a few years since Professor Hof- 

 meister expressed the view, in a noteworthy 

 lecture,^ that sooner or later appropriate, 

 specific enzymes would be discovered to ac- 

 count for each of the manifold vital chemical 

 activities of cells. The recognition of the im- 

 portance of enzymes in these diverse physio- 

 logical functions has made it easier to under- 

 stand how a minute cell can be the seat of 

 such a multiplicity of reactions, and how it is 

 possible for the latter to go on side by side in 

 the living protoplasm. Physiological chem- 

 istry has lately witnessed an unusual growth 

 of knowledge in the domain which includes 

 fermentative reactions, particularly those as- 

 sociated with the so-called intracellular or 

 endo-enzymes. The well-knowTi books of 

 Green, Oppenheimer and Effront have been 

 helpful as guides to the literature, but Dr. 

 Vernon's volume is the more welcome because 

 it reviews the newest contributions and pre- 

 sents the subject in a style that is actually 

 readable. 



It is, indeed, quite a contrast to turn from 

 the conventional chapter on pepsin and trypsin 

 written a dozen or more years ago, to the pages 

 of Dr. Vernon's lectures, in which the role of 

 the newly recognized enzymes in various bio- 

 logical processes is described. Historical per- 

 spective and not a little critique characterize 

 the author's descriptions. One becomes ac- 

 quainted with the bearing of enzymes on 

 nucleoprotein and purine metabolism; with 

 the present status of zymase and lactacidase 

 enzymes ; the perplexing problems of so-caUed 

 ^ Hofmeister, " Die chemische Organisation der 

 Zelle," Braunschweig, 1901. 



