PREFACE 



We have sought in this volume to fulfill, with respect to the chosen 

 field, the two fundamental purposes set forth at the time the American 

 Chemical Society Monograph Series was instituted. 



First, we have attempted to present the material "in readable form, 

 intelligible to those whose activities may be along a wholly different line" 

 to the end that they may gain perspective and interest and appreciation 

 of the fundamental unity existing in the broad area involving physical 

 as well as biological science. 



Second, we have sought to promote research in the field of the B vita- 

 mins "by furnishing a well digested survey of the progress already made 

 in that field and by pointing out directions in which investigation needs 

 to be extended." In connection with this latter purpose we have had in 

 mind two groups: the oncoming advanced students who from year to 

 year must have a means of becoming acquainted with the field, and the 

 ever increasing number of chemists whose fundamental training has been 

 in some other branch but who are turning to biochemistry as an attractive 

 field of investigation. 



In keeping with the title of the volume and the purposes set forth, we 

 have not included full discussions of the organic chemistry or technology 

 of the substances involved, nor have we given a historical treatment of 

 their discovery and identification. To trace all the misconceptions and 

 inevitable blunderings which have entered into the development of our 

 present knowledge and at the same time to do justice to the numerous 

 investigators would be an impossible task, and from the standpoint of 

 our purposes an attempt would not be worthwhile. 



We agree with the late G. N. Lewis' statement, "a monograph of this 

 sort belongs to the ephemeral literature of science. The studied care 

 which is warranted in the treatment of the more slowly moving branches 

 of science would be out of place here. Rather with the pen of a journalist 

 we must attempt to record a momentary phase of current thought, which 

 may at any instant change with kaleidoscopic abruptness." 



Although the four authors have found themselves to be in substantial 

 agreement on most points, in the presentation of the material in the four 

 sections they have used their respective judgments, expressed their own 



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