Note 638 — PHARMACOLOGIA. (continued 7)

Sodaic Powders.—Contained in two distinct papers, one of which is blue, the other white; that in the former consists of ʒss of the carbonate of soda, that in the latter of grs. xxv of tartaric acid. These powders require half a pint of water. It is very evident that a solution of these powders is by no means similar to “Soda Water,” which it is intended to emulate; for in this latter preparation, the soda is in combination only with carbonic acid; whereas the solution of the “Sodaic Powders” is that of a neutral salt, with a portion of fixed air diffused through it.

Patent Seidlitz Powders.—These consist of two different powders; the one, contained in a white paper, consists of ʒij of Tartarized Soda, and ℈ij of Carbonate of Soda; that in the blue paper, of grs. xxxv of tartaric acid. The contents of the white paper are to be dissolved in half a pint of spring water, to which those of the blue paper are to be added; the draught is to be taken in a state of effervescence. The acid being in excess renders it more grateful, and no less efficacious as a purgative. This preparation cannot be said to bear any other resemblance to the mineral water of Seidlitz, than in being purgative. The water of this spring, which was discovered by Hoffman about a century ago, contains Sulphate of Magnesia as its active ingredient, together with Muriate of Magnesia, and Sulphate, and Carbonate of Lime. In the Codex Medicamentarius of Paris there are two formulæ for the preparation of a water which may resemble that of Seidlitz, the one differing from the other merely in the proportion of its Sulphate of Magnesia.