Charta Potassii Nitratis (U. S. P.)—Potassium Nitrate Paper.

SYNONYMS: Saltpetre paper.

Preparation.—"Potassium nitrate, two hundred grammes (200 Gm.) [7 ozs. av., 24 grs.]; distilled water, eight hundred cubic centimeters (800 Cc.) [27 fl℥, 25♏]. Dissolve the potassium nitrate in the distilled water. Immerse strips of white, unsized paper in the solution, and dry them. Keep the paper in well-closed vessels"—(U. S. P.).

In making this preparation, which is sometimes known as asthma paper, it is essential that a paper free from chlorine and its compounds, and a potassium nitrate uncontaminated with chlorides be employed. If the medicated paper is to be used in making moxas, these precautions are not so necessary. The potassium salt should be completely dissolved, so that aggregations of the salt may not form upon the paper, thus causing the paper to burn unevenly. Medicated cigarettes may be prepared from this paper by rolling it with such leaves as those of belladonna, stramonium, digitalis, hyoscyamus, sage, etc., or the paper may be formed into a quill, whose edges are held in contact with each other by means of a little gelatin, and the medicated substance to be inhaled introduced into the hollow tube. Moxas may be prepared by rolling the nitrated paper into firm, cylindrical sticks about 1/4 inch in thickness and cutting them into sections of the desired length.

Action and Medical Uses.—This paper is to be burned and the fumes inhaled for the relief of nervous asthma. It is thought by some that the heating converts the potassium nitrate into potassium nitrite.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.