Abstract: A dispensing means (10) for delivering a dose of a first liquid into a second liquid is provided, the dispensing means comprising an enclosure (12) for the first liquid, and valve means (16), the dispensing means being operable such that raising a level (114) of a second liquid relative to the dispensing means so as to subject the dispensing means to hydrostatic pressure causes a dose of the first liquid to be displaced from the enclosure (12) to establish a column (118) of the first liquid that acts on the valve means, and subsequent lowering of the level (114) of the second liquid relative to the dispensing means so as to reduce the hydrostatic pressure acting on the valve means (16) causes the valve means to deliver the dose.