a kind of paste, sometimes hard and dry, and sometimes soft and liquid, much used in washing, whitening linens, and by dyers, fullers, &c. See CHEMISTRY, p. 93, 149, 154.

The purer hard soap is the only sort intended for internal use. This, triturated with oily or resinous matters, renders them soluble in water; and hence becomes an ingredient in pills composed of resins, promoting their dissolution in the stomach, and union with the animal fluids. Boerhaave always prescribed soap in resinous pills, unless where an alkaline or putrid state of the juices forbade its use. From the same quality, soap seems well fitted for dissolving oily or unctuous matters and viscidities in the human body; thereby opening obstructions, and deterring all the vessels it passes through. It is likewise a powerful menstruum for the calculus, or stone in the bladder; a solution of it in lime-water being one of the strongest dissolvents that can with safety be taken into the stomach: the virtue of this composition is considerably greater than the aggregate of the dissolving powers of the soap and lime-water when unmixed.