In accordance with the prevailing view that cardiac pain results chiefly from relative cardiac ischemia, any one or a combination of several primary changes in cardiovascular dynamics may be considered competent either to produce or to relieve this symptom in patients with angina pectoris, such as changes in heart rate or rhythm, systemic blood pressure, return flow, stroke volume, minute volume, and size of the coronary bed. The influence of the digitalis bodies on the foregoing functions is variable, and from the extensive pharmacologic literature observations may be assembled in the support of divergent possibilities; namely, that pain is uninfluenced, that it is increased or that it is diminished by members of this group of drugs. The experimental results which appear to have exerted a strong influence on clinical views are those which indicate that digitalis may directly constrict the coronary arteries. It is stated that through this action1