This extract is well known as an excellent covering for the taste of quinine; consequently we occasionally find the two together in mixture, with far from good results. Thus:

In this mixture a dense precipitate is formed which renders it most unsightly. So also in the following :

However dispensed a precipitate is unavoidable. Compounded as written a thick flaky precipitate is produced, which, when allowed to stand for a day, becomes tenacious and hardly diffusible. Omitting the acid, the precipitate is very fine and easily diffused through the liquid. The explanation is that liquorice extract is very readily decomposed by alkaloidal solutions, with separation of glycyrrhizin, the sweet principle of liquorice. There are several inorganic salts which precipitate the glycyrrhizin- as, for example, sodium sulphate and potassium acid tartrate. In the second prescription the acid also has an influence in inducing separation, less of it giving a better-looking mixture.

Tr. Quininae Ammon. is a preparation in which the quinine exists as hydrate kept in solution by means of the excess of ammonia and by the rectified spirit, especially the latter. Consequently when it is mixed with much water, the alkaloid is precipitated, as in the following:

Science cannot prevent the precipitation without inducing chemical change. The addition of a few drachms of mucilage of acacia is advisable. Dissolve the ammonium bromide in 4 ounces of camphor-water; add the syrup and 2 drachms of mucilage, pour in the tincture, shake gently, and make up.

There are two possible forms in which the quinine may be precipitated in a, hydrate and salicylate; the precipitate is a mixture of both, and is peculiar in being green at first and gradually changing to brown. When b is dispensed in an unthinking way, a resinous-looking separation occurs and adheres to the sides of the bottle. Dissolve the bromide in the chloroform- water; add the tincture of jaborandi, then pour in the ammoniated tincture gradually, stirring all the time. Dispensed in this way there is a slight precipitate in very small particles, which diffuse perfectly on shaking and do not adhere to the bottle.

In the case of c mix the tincture and liquor, then add the water. A clear mixture results. The spt. ammon. arom. in d precipitates the quinine as hydrate, which will not diffuse without assistance. Place 10 grains of powdered tragacanth in a dry measure, pour on it the tincture of nux vomica and the aromatic spirit of ammonia, add about 4 ounces of chloroform-water, and stir; in the mucilage thus formed dissolve the sodium bromide, add the glycerin, and make up with chloroform-water. Then place the quinine sulphate in a dry mortar and add to it the mixture gradually with steady trituration. In this way the precipitate is forcibly prevented from clotting as it is formed, and, although some of it rises to the surface of the mixture on standing, it readily diffuses by shaking.