One of the most experienced cardiologists1has estimated that serious cardiac failure is accompanied by auricular fibrillation in more than half the cases. Experienced practitioners know that extrasystoles are at least as frequent in cases coming to a doctor's office. Therefore it becomes apparent that the treatment of the cardiac irregularities is one of the important services rendered by the physician to his clientele. Moreover, the treatment of the cardiac irregularities is today, comparatively, speaking, very efficacious and easily carried out. I shall first discuss the treatment of auricular fibrillation because this makes up nearly one half of all the cases of cardiac irregularity that one has to treat and because it has a very harmful effect on the pumping mechanism of the heart. Eyster and Swarthout2have shown that the mere presence of auricular fibrillation in a dog's heart reduces the output of the heart by an