The incidence of pellagra in the Southern States has increased rapidly during the past ten years, but in spite of the advances which have been made in prophylaxis and in treatment, its etiology is still in doubt.
Various views have been advanced by investigators to explain the etiology of pellagra. These views may be divided into two classes: those which deal with it as a communicable disease, and those which consider it to be due to an unbalanced diet. Numerous organisms have been described as the etiologic agent, but sufficient proof has not yet been offered to justify us in accepting any of them. Two conceptions have been advanced by those who believe pellagra is caused by an unbalanced diet. One group of observers believes it is due to the lack of some essential substance in the diet, while the other considers it an intoxication due to the excessive use