BERIBERI 277 



may associate them with all possible conditions. If now we con- 

 sider that there is the possibility that new vitamines may yet be 

 found, we recognize the many-sidedness of the possible vitamine 

 aspects. 



The investigation of the avitaminoses is rendered more difficult, 

 in that the symptoms characteristic of these conditions may be 

 attributed to entirely different causes, aside from the deficiency of 

 vitamines. Thus, we see the development of edema, resembling very 

 much the hunger edema, which is, however, not of dietetic but of 

 infectious origin. We note beriberi-like symptoms, not related to 

 lack of vitamine B but to toxins and poisons; this is- also true of 

 many trophic appearances. Because of these complications, the 

 literature on deficiency diseases has become very clouded, since it 

 frequently happens that the finding of a case explainable by some- 

 thing other than vitamine deficiency is often followed by the attempt 

 to discredit the vitamines entirely. For these reasons, we must be 

 careful in judging the etiology of sporadic and isolated cases; it may 

 easily be .associated with an error in diagnosis. If such cases occur 

 in great number (as is usually found in practice) then a mistaken 

 diagnosis can scarcely be made. 



The vitamines have lately been associated with orthopedic surgery, 

 certain eye troubles, such as hemeralopia and ophthalmia; some 

 infections such as tuberculosis, pneumonia, leprosy; some metabolic 

 diseases such as arthritis, diabetes (also cancer) ; and with dental 

 caries. We know now that these conditions have some relation to 

 the diet but whether they are specifically associated with vitamines 

 has not yet been shown, and is in fact difficult to do so. Since many 

 of these pathological conditions, in spite of tiresome research, have 

 given no real explanation, we see no harm if vitamine research will 

 give a new impulse to the study of these questions. We see many 

 examples of how a misleading hypothesis has led to a favorable 

 solution of some questions; at any rate, if a subject remains quiescent 

 it can never lead to progress. 



In the description of beriberi, we shall dwell exclusively on 

 the human type, since many phases of this question have already 

 been treated in avian beriberi. Above all, we recommend to the 

 reader who is particularly interested in beriberi the fundamental 

 work of Vedder (838) as well as to contributions by Castellani and 

 Chalmers (839) and Schilling (840), who treat the subject from the 



