(from λίθος, "a stone," and ἀποπλάνη, "to break"); an epithet for medicines that are supposed to break the stone in the bladder. Though the different stones that are generated in the human bladder require different solvents when out of the body; and though art hath not yet afforded a medicine which, when injected into the bladder, will, without injury thereto, dissolve the stone therein lodged; it cannot thence be concluded, that there are no lithontriptic medicines. It may be here observed, that one solvent affects one subject, but hath no effect on another; so a solvent may yet be met with that will destroy the stone, and not hurt the human body. The water into which the boiled white of egg dissolves will liquefy myrrh, but may be put into the human eye without causing any uneasiness.

Soap ley taken at first in small doses in broth that is freed from all its fat, succeeds in most cases which require an alkaline solvent. The patient may begin with 20 drops, and gradually increase the dose as he is able; and by repeating it three times a-day for six, eight, or twelve months, the wished-for effects often follow.