[This plant is found in almost every part of the United States in low and moist situations. It flowers in May and June, and the root is the only part used in medicine. By analysis this is found to contain resin, bitter extractive, fœcula, and a slight proportion of a gummy substance. The root of the May Apple is an excellent active cathartic, operating in a manner very similar to the common Julap. It is given in powder, in doses of about grs. xx. The proper period for collecting the root for medicinal purposes is the autumn, when the leaves of the plant have turned yellow. It should be carefully dried and then pulverized.]
POTASSA CUM CALCE. L.E.
Kali Causticum cum Calce. D.
The addition of lime to potass renders it less deliquescent, and more manageable, as an escharotic.
POTASSA FUSA. L.
Potassa. E. Kali Causticum. D.
Lapis infernalis. P.L. 1720.
Qualities. Form, a white brittle substance, extremely caustic and deliquescent, and possessing in an eminent degree all the properties denominated alkaline. Solubility. f℥j of water dissolves ʒvij; it is also soluble in alcohol. Chemical Composition. This preparation, independent of its impurities, is the hydrated protoxide of potassium, although in the state in which it is cast into sticks it generally contains a little Peroxide,[[608]] and therefore evolves oxygen when dissolved in water. Med. Uses. It is a most powerful caustic (causticum commune acerrimum), and is frequently employed to establish an ulcer; or, instead of incision, to open a tumour. It has the advantage of other caustics, from the circumstance of our being able to neutralize its powers by touching it with vinegar, and thus to arrest its progress in an instant; it is however more liable to produce a large eschar than nitrate of silver, in consequence of the chemical action of the alkali upon the skin. Within the last few years, surgeons have greatly preferred the use of this caustic to that of nitrate of silver, in cases of organic stricture of the urethra, as acting more powerfully, and yet occasioning less irritation than the latter substance; it is also said that the part which it destroys is sooner detached and more easily eliminated. Its disposition, however, to extend its sphere of action has occasioned such a destruction of the membrane as to allow the urine to pass into the cellular substance, by which very serious effects have been produced. For this reason there are cases in which the nitrate of silver is still to be preferred. As an internal remedy it is only employed in solution. See Liquor Potassæ.[[609]]
POTASSÆ ACETAS. L. Acetas Potassæ. E.
Acetas Kali. D. Kali Acetatum. P.L. 1787.—Sal diureticus. P.L. 1745.—Terra foliata Tartari.—Sal Sennerti.—Magisterium Purgans Tartari.—Sal Essentiale vini. Oleum Tartari Sennerti.—Sal digestivus Sylvii, &c.