PREFACE 



IT was in the first instance my intention to present to English readers 

 a translation of Dr. Otto Cohnheim's Chemie der Eiweisskorper, the first 

 book of its kind dealing with this abstruse subject. In the perform- 

 ance of my self-imposed task I found, however, that, apart from 

 bringing the subject-matter up to date, there was room for extension, 

 and on certain questions it seemed to me necessary to express opinions 

 at variance with those held by the -distinguished author. Under these 

 circumstances it soon became apparent that the work, as presented 

 now to the reader, was no longer a transcript of the German text- 

 book, so that, whilst readily admitting that the present volume is 

 largely based on Dr. Cohnheim's second edition, I thought it better 

 to incur the entire responsibility for all matter therein contained, 

 whilst publicly admitting my indebtedness to Professor Otto Cohnheim 

 of Heidelberg. Proof-sheets of this book were submitted to Professor 

 Cohnheim, and my action in regard to this matter has met with his 

 entire and cordial approval. 



The points on which special stress has been laid are as follows : - 



1. Cellular metabolism is a cyclic event and not a question of 



anabolism and katabolism. That, throughout, the biological 

 aspect of chemistry has been specially kept in mind will 

 be seen by referring to the Index under the heading of 

 'Physiological considerations.' 



2. Every care has been taken to give each investigator his due, for 



I hold Science to be above any consideration of nationality. 

 The reactions in daily use have all been traced back to their 

 originators, and in the chapter dealing with the synthesis of 

 albuminous compounds the respective merits of the different 

 workers have been duly set forth. 

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