... criterion of the condition Of the circulation. There is always a certain amount of heart block associated with auricular fibrillation so that not all of the auricular stimuli pass through the bundle of His. James and Hart determine the heart rate both at the radial pulse and at the apex, the difference being called the pulse deficit. They use this deficit as an aid in deciding when to stop the administration of digitalis. When the pulse deficit is zero, the digitalis is stopped. In this connection they also ... — DISTURBANCES OF THE HEART • OLIVER T. OSBORNE, A.M., M.D.