Recently Schoonmaker and Webb1reported a case of auricular fibrillation in a toxic adenoma of the thyroid. Because of the great improvement noted in all symptoms in this case and the rarity of this condition among our patients with goiter we thought it worth while to investigate the literature on this subject. In looking through the literature we find that as yet not many cases have been reported in detail, and that as a rule there are only incidental references to cases of goiter in descriptions of various cardiac conditions. However, that auricular fibrillation is not rare in goiter is shown by Willius2who stated that at the Mayo clinic 7 per cent. of patients with exophthalmic goiter and 9 per cent. with hyperactive adenoma have auricular fibrillation on admission, and that these figures were doubled while the patients were under observation. Willius and Boothby3in a more recent paper,