While the cell is the basic biological unit, the contractile chamber follows closely in fundamental importance. Understanding the heart, the circulation and other systems in the body requires one, first, to recognize that common factor and basic unit, the contractile chamber. The heart is just one of many organs composed of contractile chambers. Some individuals do survive, despite a period when their hearts appeared to be doing little or nothing. Cases are cited which illustrate this seeming discrepancy between cardiac delinquency and patient's longevity. Some extra-cardiac propulsive mechanism must be identified to explain such cases. The extrapericardial vessels contain muscles which must have a dynamic role in the circulation of blood, supplementing, complementing, and perhaps even replacing cardiac action. In addition to transplants, and artificial hearts, the possibilities of enhancing the role of the extra-cardiac circulatory mechanisms (already provided by nature) should be studied.