Abstract: The desired invention concerns a syringe with a double compartment. The first compartment (10) is bounded by a first cylinder (12), closed off at one end by a first partition (13) in which an opening (15) is provided, and at its other end by a first sliding piston (14). This syringe also contains a second cylinder (17) coaxial to and inside of the first cylinder, attached at its first extremity to the first piston and closed of at its second extremity by a second partition (18), and an axial rod (16), coaxial to and inside of the secnd cylinder, that is attached to the first partition by its first extremity, sliding across the first piston (14) and supporting at its other extremity a second piston (19) that slides into the second cylinder. In this manner, a second compartment is formed by the second cylinder, the second piston, and the second partition, the volumes contained in the two compartments fluctuating simultaneously when the second cylinder is shifted in relation to the first one.