PROLOGUE 



A logical consideration of the role of the B vitamins in living organisms 

 might well follow an outline centering around the answers to these four 

 major questions: 



What are the B vitamin requirements of living organisms? 



What happens to the B vitamins in living organisms? 



How do the B vitamins affect living organisms? 



How does B vitamin deprivation affect living organisms? 

 The first three chapters of this section are an attempt to answer the 

 first of these questions, while the ensuing chapters are devoted respec- 

 tively to the last three questions. The answers, however, are by no means 

 as explicit as are the questions. 



