Since the time when Billroth characterized the operation of tapping the pericardium as "a surgical frivolity and a prostitution of surgical skill," the pericardium has assumed a more important place in surgery. The pericardial cavity has been aspirated for fluid, and it has been incised for pus. It has been opened for the suture of cardiac wounds, for the removal of foreign bodies and for relief from valvular stenoses. The pericardium has been excised when involved by neoplasms. It has been excised, sometimes with the precordial ribs, for adhesive pericarditis and for cardiac hypertrophy. It is apparent that the pericardium has entered the domain of surgery for numerous reasons, and we believe that a fuller appreciation of its pathologic physiology will give it a place of even greater importance than it has held in the past.
Despite the notable progress that has been made along these various lines of endeavor,