vi TRANSLATOR'S PREFACE. 



use of the words protein and proteid. While this book was in press the 

 "Joint Recommendations of the Committees on Protein Nomenclature" 

 was published in Science, in which the first recommendation was that the 

 word proteid should be abolished. They would call what Dr. Abder- 

 halden designates as proteids the conjugated proteins. The confusion 

 with regard to the word proteid has arisen from the fact that some writers 

 have designated as proteids the whole protein group, while others have 

 used the word only for these compound proteins. It was too late to 

 adopt the recommended nomenclature, as many of the plates were already 

 cast. It seems probable, however, in view of the rapid progress which is 

 now being made in this branch of chemistry that before long we shall be 

 able to adopt a chemical classification of the proteins which shall be 

 better than any yet proposed. 



It has not seemed best to give all of the titles to the papers cited in 

 the footnotes. Most of these titles which appear in the original lectures 

 are in German, and in some cases they were evidently taken from the 

 Centralblatt and are German translations of English titles. It seemed 

 sufficient to give merely the abbreviated titles of the journals where the 

 references could be found with the volume and page. The abbreviations 

 used are, in the main, those adopted by the American Chemical Society 

 in their Chemical Abstracts, the principal ones being given in the front of 

 this book. 



Dr. Abderhalden has kindly looked over all of the "page proof" and 

 has suggested numerous changes bringing the literature in some cases up 

 to 1908. Professor F. Jewett Moore of the Massachusetts Institute of 

 Technology as well as Dr. Percy G. Stiles of Simmons College and the 

 Institute of Technology have also read all of the proof and have rendered 

 invaluable aid by their many suggestions and criticisms. If this trans- 

 lation meets with the same friendly reception that has been accorded to 

 the original, credit is due fully as much to each of these two gentlemen 

 as to either one of the translators. 



WILLIAM T. HALL. 



MASSACHUSETTS INSTITUTE OP TECHNOLOGY, 

 July 11, 1908. 



