276 THE VITAMINES 



personal conception of the cases quoted, which is now usually quite 

 impossible. Since our first edition, no great progress has been 

 made because of the above reasons, in spite of many publications. 

 The conditions regarded at that time as avitaminoses are con- 

 sidered as such to the present day, while the suspected avitaminoses 

 are still as uncertain as before. The author, as the originator of 

 this classification would like to see all these conditions demonstrated 

 as avitaminoses; on the other hand, it would be worth while to elim- 

 inate as soon as possible all that does not belong to this complex. 



Even as regards the definite avitaminoses, we are well aware that 

 there will always remain a minority who will have a different opinion 

 from ours. While we recorded all of these divergent opinions in our 

 first edition, we believed it necessary, from the point of view of uni- 

 formity of the subject, to avoid this at present. It should, however, 

 not be thought that we wish to ignore the opponents of the vitamine 

 subject. This book is intended to treat of vitamines and we shall 

 not stray from its main purpose. 



What has just been said applies even more to the description of 

 those pathological conditions which cannot possibly be regarded as 

 avitaminoses, but in which the presence or absence of vitamines may 

 play a part. The consideration of these conditions in this book 

 should, however, not be construed to indicate the author's belief 

 that they may be related to the vitamines directly. It is possible 

 that some of the diseases to be described here may in the future be 

 explained differently. This book merely pictures the possible 

 aspects of future vitamine study, and does not exclude another solu- 

 tion of the problems. 



The reader may ask why an answer to the above problems is not 

 yet at hand. Why can we not say whether or not a certain condition 

 can be associated with the vitamines etiologically? Apart from 

 the fact that the vitamines are indisputably essential for life, we 

 know very little regarding their physiological significance. To be 

 sure, we see signs of a generally diminished assimilative ability, 

 negative balances of some important inorganic and organic constitu- 

 ents, and decreased resistance to infection. Besides this, we see 

 changes in most organs, in the glands of internal and external secre- 

 tion, and trophic changes in the skin. But just how all these con- 

 ditions can be correlated with the lack of vitamines is at present 

 unknown to us. The above list of symptoms is so large that we 



