A dual chambered syringe includes: an inner barrel defining a first inner chamber, the inner barrel having an apertured stopper at its distal end, the inner barrel being open at its proximal end； a shaft adapted to fit within the inner barrel, the shaft having a distal end which is engageable with the aperture of the stopper； a device for controlling engaging and disengaging of the distal end of the shaft with the aperture of the stopper； an outer barrel concentric with the inner barrel defining a second inner chamber, the outer barrel having a distal end for receiving and dispensing fluids and a proximal end into which the distal end of the inner barrel is insertable into the second inner chamber； the apertured stopper engages the second inner chamber of the outer barrel and selectively prevents or permits the passage of fluids between the outer barrel second chamber and the inner barrel first chamber； the inner barrel having an engageable surface on its outside surface； and, the outer barrel having operatively associated therewith an engaging device for selective engagement and disengagement with the engageable surface on the inner barrel.
