PREFACE 



The story of \itamins i-esembles, in many ways, the story of the Tower 

 of Babel. What once seemed simple has become confounded; what once 

 could be mastered by a few is now only partly understood by the many. 

 The ver\^ large number of publications dealing with the many aspects of 

 vitamin research confronts the investigator and practitioner like a strange 

 and newly discovered land, each area with its own special interests. 



In this book the editors have attempted to provide, as it were, a guide 

 service to these new and complicated areas. Just as guides are chosen for 

 their special knowledge of each specific region, so each contributor to this 

 work has been chosen for his competence in a specific field. For this reason 

 no contributor has discussed one vitamin entirely, and some have discussed 

 the same aspect of knowledge regarding several vitamins. This method will 

 force the reader to change guides as he progresses through each chapter, 

 but it will assure a higher level of competence than if one guide were to 

 attempt to summarize critically and to present adequately the current 

 knowlege concerning the chemistry, industrial production, physiology, bio- 

 chemistry, estimation, occurrence, deficiency effects, pharmacology, and 

 requirements of each vitamin. Since this is essentially a reference work, 

 some repetition of information in the various sections of each chapter is un- 

 avoidable and even desirable. 



Neither the clinical manifestations of vitamin deficiencies nor their treat- 

 ments have been presented in detail, since they are adequately covered in 

 other publications. For the same reason, the methods of vitamin assay are 

 discussed but briefl3\ 



Special emphasis has been given to the chemistry and physiology of the 

 ^•itamins. This compelled the omission of historical material, except where 

 it bears importantly on current knowledge. An extensive bibliography has 

 l)een included so that the student can readily consult original material. 



The vitamins are presented alphabetically because there is no biological 

 reason why they should be arranged otherwise. 



The editors want to express their appreciation to the authors for their 

 scientific devotion and to the publisher for his unending patience. They 

 will feel repaid for their labors if this work contributes to a better under- 

 standing of the role of vitamins and stimulates further research, for it has 

 been said triUy: 



Wisdom is (he principal thing; therefore get wisdom; and with 

 all thy getting gel understanding. — (Proverbs IV. 7) 



W. H. Sebrell, Jr. 

 Robert S. Harris 



