Contractions. - Merc. Mer.

Mercurius solubilis Hahuemannii. Impure Hg2O.

This preparation has an historical interest, as it was discovered by Hahnemann; it is, however, most unsatisfactory in a pharmaceutical sense. The process for making it is needlessly complex, and it is difficult to insure any two consecutive preparations being alike. Therapeutically, however, it seems to act well, although in this respect it is in no way different or superior to Mercurius vivus, which, if well prepared, is pharmaceutically much more trustworthy. According to Jahr, Hahnemann entirely abandoned this preparation in favour of Merc. vivus many years before his death.

The process recommended by Hahnemann is as follows: -

"Having purified the Mercury, it is dissolved, cold, in common Nitric Acid, which requires many days; the salt which results is dried on blotting-paper, and triturated in a glass mortar for half an hour, adding one-fourth of its weight of the best alcohol. The alcohol which has been converted into ether is thrown aside, and the trituration of the Mercurial is continued with fresh alcohol, for half an hour each time, until this fluid no longer has the smell of ether. That being done, the alcohol is decanted, and the salt dried on blotting-paper, which is renewed from time to time. Afterwards it is triturated for a quarter of an hour, in a glass mortar, with twice its weight of distilled water; the clear fluid is decanted, the salt is again washed by a second trituration with a fresh quantity of water, the clear fluid is united to the preceding, and thus we have the aqueous solution of all that the saline mass consisting of Mercurial Nitrate really saturated. The residuum is composed of other Mercurial Salts, of Chloride and Sulphate. Finally, this aqueous solution precipitates, by Caustic Ammonia, the so-called Black Oxide of Mercury (Blackish-grey Oxidule of Mercury)."

From the time stated to be required to dissolve the Mercury, it is evident that a subnitrate was formed. To secure uniformity in the preparation of this subnitrate, the following formula is suggested as being in accordance with Hahnemann's directions: -

Take of

Mercury .....

4 ounces;

Nitric Acid, sp. gr. 1.2 . . .

9 fluid ounces.

Macerate at a temperature below 70° for a week or ten days, then separate the crystals which have formed from any metallic Mercury which may remain undissolved, dry them, and proceed as directed above.

Preparation. - Trituration.

Reference to Horn. Proving. - R. A. M. L., i.

Proper forms for dispensing. - lx to 3, Trituration only. 4, dilute Tincture only. 5 and upwards, Tincture, Pilules, or Globules.