Abstract: A dispenser for dispensing a metered amount of a liquid comprises a body having sidewalls defining a hollow interior and an opening at a forward end of the body, a cartridge having a reservoir adapted to contain a liquid and an outlet at the forward end of the cartridge, the cartridge being sized and shaped to be positioned in the hollow interior of the body so that the outlet is aligned with the opening in the body. A plunger is positionable in the reservoir and slidable within the reservoir, and a metering unit comprises a plunger advancement mechanism that can cause the plunger to slide within the reservoir, the metering unit causing the plunger advancement mechanism to advance the plunger a predetermined amount. The metering unit is configured to cause advancement the plunger in the reservoir to apply pressure on the liquid in the reservoir and cause a droplet of the liquid to be dispensed through the outlet. The dispenser produces a droplet of from about 0.5 ?l to about 10.0 ?l.