Hypodermic syringe

Claim 1

A SYRINGE, COMPRISING: A CYLINDER STRUCTURE HAVING A DISCHARGE END ADAPTED TO RECEIVE A HYPODERMIC NEEDLE; A PLUNGER STRUCTURE INCLUDING A PISTON AXIALLY MOVABLE IN SAID CYLINDER STRUCTURE AND A STEM EXTENDING FROM SAID PISTON THROUGH THE END OF SAID CYLINDRICAL STRUCTURE OPPOSITE FROM SAID DISCHARGE END; A SEAL FOR SAID STEM FITTED IN SAID OPPOSITE END, SAID PISTON INITIALLY OCCUPYING A POSITION INTERMEDIATE THE ENDS OF SAID CYLINDER STRUCTURE, SAID STRUCTURES INITIALLY DEFINING AT LEAST TWO ISOLATED COMPARTMENTS ON OPPOSITE SIDES OF SAID PISTON, ONE OF SAID COMPARTMENTS SURROUNDING SAID STEM; AND INITIALLY CLOSED VALVE MEANS CARRIED BY SAID PLUNGER STRUCTURE AND SEPARATING SAID COMPARTMENTS, SAID VALVE MEANS ADAPTED TO OPEN ON MOVEMENT OF SAID PLUNGER STRUCTURE AWAY FROM THE DISCHARGE END OF SAID CYLINDER STRUCTURE TO PERMIT INTERMIXING OF THE CONTENTS OF SAID COMPARTMENTS, SAID VALVE MEANS ADAPTED TO CLOSE IN RESPONSE TO MOVEMENT OF SAID PLUNGER STRUCTURE TOWARD THE DISCHARGE END OF SAID CYLINDER STRUCTURE TO DISCHARGE THE MIXED CONTENTS OF SAID COMPARTMENTS THROUGH SAID DISCHARGE END.