| abstract |
A delivery apparatus for selectively delivering one or more liquid reagents into a reaction or test chamber ( 2 ), especially of an assay apparatus, the apparatus comprising: one or more respective storage chambers ( 5,6 ) for containing the one or more liquid reagents and arranged generally above the reaction or test chamber ( 2 ); and a plunger element ( 4 ) arranged and operable for insertion into the mouth of a selected storage chamber so as to displace a selected reagent from therewithin into the reaction or test chamber ( 2 ) generally therebelow by gravitational liquid overflow from the mouth of the chamber. The apparatus may conveniently be provided as a discrete delivery unit, with the storage chambers ( 5,6 ) prefilled with the selected reagents. |