A liquid dispenser includes a downwardly inclined slide surface. A carrier liquid dispensing channel includes an outlet that exits onto the downwardly inclined slide surface. A carrier liquid source provides a carrier liquid that flows continuously through the carrier liquid dispensing channel, through the outlet of the carrier liquid dispensing channel, and down the downwardly inclined slide surface. A functional liquid supply channel includes an outlet that exits onto the downwardly inclined slide surface. A functional liquid source provides a functional liquid to the outlet of the functional liquid supply channel. A drop formation device, associated with an interface of the outlet of the functional liquid supply channel and the downwardly inclined slide surface, is selectively actuated to form a discrete drop of the functional liquid in the carrier liquid flowing down the downwardly inclined slide surface. The functional liquid is immiscible in the carrier liquid.