The plunger 20 is preferably {HEAD ~ a standard syringe plunger} formed of Polystyrene or {TAIL ~ Polypropelene} and comprises a shaft 26 having a cross section which is a cruciform, i.e. X shaped, as best illustrated in FIG 4 
The plunger 20 is preferably { HEAD ~ a standard syringe plunger } formed of Polystyrene or { TAIL ~ Polypropelene } and comprises a shaft 26 having a cross section which is a cruciform , i.e. X shaped , as best illustrated in FIG 4
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH