Abstract: A device and method for movement and measurement of fluid volumes involves defining a fluid volume in a measuring chamber of a rotation vessel by at least first and second pistons movable within the measuring chamber, with the first and second pistons separating and indicating the volume of fluid moved into and out of the measuring chamber via flow-regulating valves. A holding means alternately holds the first and second pistons at fixed positions within the measuring chamber while the other piston rotates. A device and method of respiration involves a respirator including a plurality of flexible gas bags and a stiff gas tank with a first flexible gas bag positioned inside a second flexible gas bag and both gas bags being positioned inside the stiff tank. The respirator is connected to the device for the movement and measurement of fluid volumes via respirator valves.