Researches in blood oxygenation through a membrane, in an extracorporal circuit, with the physiological flow of an adult and an oxygen saturation have led up, by experimental way, to use dissolved oxygen. The membrane is a plastic microporous film coating a strong textile support which constitutes a cylindrical rotor. The rotor micropores are crossed through by a pH 7.4 phosphate buffer aerosol which conveys the oxygen. This aerosol is dropped in the revolving rotor. Venous blood which spreads out on the external surface of the rotor is immediately hematosed in contact with the atmospheric pressure with free release of carbon dioxide without microbubbles formation. The low pressure which prevails in the rotor is maintained only when the membrane is hydrated by the aerosol. To do that, it is enough to maintain the hydratation by a buffer drip: one drop per second can be enough. During the high flow open-heart operation of an adult patient, the curves of physiological constants remain normal. The membrane is perfectly stable during the period it is used. In France, according to François de Gaudard d'Allaines, this equipment has allowed "the adult first open-heart operation with extracorporal circulation" (1958). About sixty operations have been realized under the responsibility of François de Gaudard d'Allaines and myself.