This device comprises means for supporting a first and a second chamber,
means for allowing these chambers to communicate with each other, and a
movable member for applying a suitable force to reduce the volume of the
first chamber. The means for supporting the first and second chambers
comprise two tubular bodies, each open at one end, the dimensions of
these openings being such as to allow these tubular bodies to be brought
together and slid one into the other, a double-ended needle, with
associated guide means, being interposed between the said chambers in
such a way that when the said tubular bodies are slid towards each other,
the respective ends of the said needle pass into the chambers and the
volume of the chamber is reduced.