Scope and Contents Sequence: Testing of valves; testing machine; tricuspid valve on high speed pictures; bad valve in tester; natural valve of a dog in testing machine; polyurethane valves; placement of a tricuspid valve in a dog (natural heart); cineangiocardiogram of mitral in a dog; rubber valves in testing machine; valve in a natural heart showing clot; plastic patches for clot investigation; clots in plastic valve in a dog's heart; woven Teflon valves, clotted. 20 minutes.