INTRODUCTION 



The first edition of this book, drafted seven years ago, was intended 

 to serve the purpose of directing the attention of the medical and 

 chemical professions to this new and attractive field of investigation. 

 The findings upon which we based our views in 1913 appeared indeed 

 to be far from indisputable but time has shown the comparative 

 accuracy of our conception. Since then, we have made it a point 

 to note any work that might have some bearing upon the question 

 of the vitamines, and have now undertaken to point out what may 

 be regarded as erroneous and what may be looked upon as correct, 

 in the light of the present status of the subject. 



Our original classification included beriberi, scurvy and Barlow's 

 disease as true avitaminoses, while pellagra, sprue, rickets, 'and some 

 metabolic diseases of animals, were held to be hypothetical avitam- 

 inoses. At present, beriberi, scurvy and Barlow's disease are uni- 

 versally accepted as true avitaminoses, while rickets is quite generally 

 acknowledged as such. The etiology of pellagra and sprue, on the 

 other hand, has not yet been definitely established. Regarding 

 pellagra, which we shall discuss later, the dietetic hypothesis is at 

 present in the foreground. 



As for the chemistry of the vitamines, an examination of the 

 literature reveals little progress in this direction. To be sure, one 

 must bear in mind that the outbreak of the war was not particularly 

 conducive to the long and tedious research that is necessary, if this 

 phase of the subject is to be cleared up. From tune to time, word 

 comes from this or that laboratory to the effect that the puzzle has 

 been solved that progress has been made even towards the synthesis 

 of the vitamines but after much patient waiting, nothing more is 

 heard of the discovery. However, since a large part of the experi- 

 mental work is being carried on in many industrial research labora- 

 tories, it is quite possible that definite important progress has been 

 made, of which reports have not yet been published. 



Incidentally, the war has given added impetus to vitamine research 

 in another direction. The vitamines have now become of great 

 importance from the point of view not only of pure science and medi- 

 cine, but also of political economy much greater than could have 



15 



