This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Tamarindus Pharm. Lond. & Edinb. Oxyphaenicon. Tamarind: the fruit of a pretty large tree, (siliqua arabica qua tamarindus C. B. Tamarindus indica Linn.) growing in Arabia and in the East and Well Indies. The fruit is a pod, somewhat resembling a bean-cod, including several hard seeds, together with a dark-coloured viscid pulp: the East.India tamarinds are longer than those of the Weft, the former containing six or seven seeds each, the latter rarely above three or four: they never-theless seem both to be the produce of one species of plant. The pulp, with the feeds, connected together by numerous tough firings or fibres, are brought to us freed from the outer shell: the oriental sort is drier and darker coloured than the occidental, and has more pulp: the former is sometimes preserved without addition, the latter has always an admixture of sugar.
The pulp of tamarinds is an agreeable laxative acid; of common use in inflammatory and putrid disorders, for abating thirst and heat, correcting putrefaction, and loosening the belly. The dose, as a laxative, is two or three drams: an ounce or two prove moderately cathartic. It is an useful addition to the purgative sweets, cassia and manna, increasing their action, and rendering them less liable to produce flatulencies: the resinous cathartics are said to be somewhat weakened by it. Tournefort relates that an essential salt may be obtained from tamarinds, by dissolving the pulp in water, and setting the filtered solution, with some oil upon the surface, in a cellar for several months; that the salt is of a sourish taste, and difficultly dissoluble in water; and that a like salt is some-times found also naturally concreted on the branches of the tree. The salt, as Beaume observes, may be obtained more expeditiously, by clarifying the decoction of the tamarinds with whites of eggs, then filtering and evaporating it to a proper consistence, and setting it to cool: the salt shoots into crystals, of a brown colour, and very acid taste; but in dissolving and crystallizing them again, or barely washing them with water, they lose almost all their acidity, the acid principle of the tamarinds seeming not to be truly crystallizable.