The symptoms and signs of concretio cordis as a type of obstructing pericarditis were clearly described by Volhard and Schmieden1in 1923. They measured the venous pressure and found that it was elevated. Beck and Griswold2in 1930 were able to produce in dogs constricting pericardial scars associated with an elevated venous pressure, a diminished cardiac output, a small pulse and edema. Resection of these scars was followed by a fall in the venous pressure, a rise in the cardiac output and a diminution in the edema. Burwell and Strayhorn3in 1932 reported quantitative studies of the circulation in a young man subsequently proved to have concretio cordis. He exhibited a high venous pressure, a small pulse pressure and a diminished cardiac output per minute and per beat. Exercise was associated with an increase in the arteriovenous oxygen difference; but no increase occurred in the output per