ascorbic acid and vitamin A and the rapid improvement and return to normal of the tongue when vitamin B6 was administered constitute, we believe, experimental evidence of a vitamin B" (pyridoxine) deficiency.We have observed, in addition, a stomatitis characterized by the persistence of redness of the mucosa and the presence of many small plaques, looking like milk curds, which could not, however, be washed or rubbed off the mucous membrane. The exact nature of the deficiency causing the stomatitis is not known. We have found