To one who for many years enjoyed the privilege of friendship with Frank Billings, and who admired both his character as a man and his acumen as a clinician, it is a source of gratification to be invited to deliver this annual lecture which perpetuates his name. It is natural, I think, in such circumstances, to cast around for some subject in which Frank Billings himself was interested, and among the many topics on which he wrote was pericarditis.1For this reason I have chosen to speak today on a particular type of this disease; namely, the so-called pericarditis epistenocardica. DEFINITION OF THE TERM I would remind you, first of all, that it is only in recent years that we have been able to differentiate the angina pectoris of effort from coronary occlusion, and I would point out that, in the past, both conditions were described in the literature