editor's note ix 



The authors' names are given in bold-face type in the cita- 

 tions in order to facihtate reference to original papers. Idem 

 denotes a repetition of the author's name while /^?(/. indicates 

 a repetition of the name of the serial next preceding. Most of 

 the abbreviations of serial names are those in general use. 

 Biochem. Z. is used for Biochem. Zeitschr. for the sake of 

 brevity, in view of the large number of citations from this 

 journal. In the case of the names of monographs in Russian, 

 the titles are left in the German version, followed by the word 

 "Russian." 



The index has been enlarged over the original by the insertion 

 of more detailed subject entries and by the compilation of an 

 index to the authors which is merged with the subject index. 

 Authors' names are placed in bold-face type as are the pages on 

 which such names appear in a complete citation. 



Dr. Kostychev took advantage of the opportunity to correct 

 certain errors in the German edition and these changes have 

 been incorporated without comment. A few new paragraphs 

 have been inserted by him, notably those dealing with War- 

 burg's theory of respiration (pages 113-116). This edition is 

 therefore brought up-to-date by the editorial notes and by all 

 changes and additions made in the author's private copy which 

 was kindly loaned to me for the purpose. 



The entire manuscript has been carefully read by my col- 

 league, Mr. George M. Robertson, who has contributed valu- 

 able advice and criticism, for which I am grateful. I also 

 tender my thanks to Prof. C. E. Bolser and Prof. R. W. Jones, 

 of Dartmouth College, and to others who have assisted in the 

 determination of certain troublesome points. I gladly acknowl- 

 edge the material assistance rendered me by the Sigma Xi 

 society which advanced the cost of the translation rights through 

 its Committee on Award of Sigma Xi Aid to Research. 



Charles J. Lyon. 



Dartmouth College, 



Angtiit, 1927. 



