"Take of the hydrochlorate of morphia, one ounce; of solution of ammonia, Jive fluid drachms; of distilled water, a pint. Add to the solution of ammonia diluted with an ounce of distilled water, the hydrochlorate of ammonia dissolved in the remainder of the water. Wash the precipitate in distilled water, and dry it with a gentle heat."

In this process, the superior affinity of the ammonia than the morphia for the hydrochloric acid, occasions the decomposition of the hydrochlorate; the morphia being little soluble is thrown down, and hydrochlorate of ammonia remains in solution.

Qualities. - Pure morphia, by this process, is thrown down in a flocculent form; but when it is stirred and left at rest, it crystallizes: but it is most perfectly crystallized when it is dissolved in alcohol. Its crystals are six-sided prisms, with dihedral summits. They consist of 1 eq. of anhydrous morphia=288.23 + 2 eq. of water = 18, making the equivalent =306.41.1 The anhydrous salt consists of-

This salt is almost insoluble in cold, and sparingly so in boiling water. It is readily soluble in 40 parts of alcohol at 60°, and in 30 at 212°; and in the fixed and volatile oils: but it is scarcely soluble in aether. The pure alkalies dissolve it. Nitric acid decomposes it, forming at first a red solution, which becomes yellow, and is converted into oxalic acid. Persalts of iron give it a blue tint. When added to iodic acid, it decomposes the acid, and evolves iodine.

Medical properties and uses. - Owing to its little solubility, morphia is rarely employed as an internal remedy., I have employed it with great advantage as an external application, sprinkled on blistered surfaces, in neuralgia, spasm, and stiff joints. If more than two grains be thus used for one sprinkling, it causes inconvenient narcotic effects.

1 Liebig.

Officinal preparations. - Morphia Acetas, L. Morphia Hydro-chloras, L.