This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Althaea Pharm. Lond. & Edinb. Althaea diqscoridis & plinii C. B. Althaea officin. Linn. Marshmallow: a soft hoary plant: with oblong undivided leaves; and pale flesh-coloured monopetalous flowers, cut deeply into five sec-tions, set in a double cup, the outermost of which is divided into nine parts, the inner into five: the fruit consists of a number of capsules, set in form of a flat disk, containing each a single seed: the roots are long and (lender, with several fibres, of a pale yellowish colour on the outside, and white within. - It grows wild in marshes and other moist places, though frequently cultivated in gardens. It is perennial, and flowers from June to near the end of summer.
All the parts of althaea abound with a glutinous juice, of scarcely any smell or particular taste. The dry roots, boiled in water, give out near half their weight of gummy matters which, on evaporating the aqueous fluid, forms a flavourless, yellowish mucilage. The leaves afford scarcely one fourth their weight, and the flowers and seeds still less; though the two latter have been looked upon by some as the most mucilaginous, and accordingly prescribed in less quantity (a) than the other parts of the plant.
Of all the mucilaginous vegetables, marsh-mallow root is, among us, of the most general use; for obtunding and incraffating acrimonious thin fluids, in tickling coughs from de-fluxions on the fauces and lungs, in hoarseness, erosions of the stomach and intestines, difficulty and heat of urine; and for lubricating and relaxing the passages in nephritic and calculous complaints.
The root is sometimes given in powder, from a scruple to a dram or two, either by itself, or in conjunction with other materials of similar intention, as gum tragacanth, starch, etc. It is rather too bulky, however, for this form; and may, in most cases, be taken to better advantage in that of an infusion or decoction, sweet-ened with a little liquorice: an ounce of the dry root is sufficient for a quart or three pints of water, a larger proportion rendering the liquor disagreeably slimy. - A syrup, made by boiling a pound of the fresh roots in a gallon of water till half the liquor is wafted, pressing out the decoction, and after fettling for a night, boiling it down with four pounds of fine sugar till the weight of the whole is six pounds, is kept in the shops, and employed occasionally in some disorders of the breast, and for sweeten-ing emollient decoctions in nephritic cases.
(a) Geoffroy, mat, med. ill. 73.