Fluid passing apparatus with means for covering the same

Apparatus for passing a fluid into or out of a warm-blooded animal which includes a fluid containing body (4), a needle assembly (24) releasably mountable on the exterior surface of the body, a plunger (14) for urging fluid into or out of the body and an externally mounted cap (34) or retraction device for automatically covering the needle after it has been used and preventing the needle from reentering the aperture in the body.