Hollow-needle device (100) comprises a hollow plunger (105), a body part affording a cylindrical chamber (101) within which the plunger (105) is sealingly slidable, a needle-carrying hub (120) for automatic retraction into the plunger (105), and a closure (130) for the plunger (105). The closure (130) comprises a member (131) normally in sealing relation with end-adjacent internal provision (133) of the hollow plunger (105) but disengageable therefrom and bodily movable into the hollow plunger (105) by localised first engagement (135) of the member (131) at or near end of contents expression stroke of the plunger (105). |