Adulterations. The ordinary acid of the shops contains in general 3 or 4 per cent. of saline matter, which consists of about two-thirds of sulphate of potass, and one-third of sulphate of lead. Dr. Ure observes, that even more is occasionally found, in consequence of the employment of nitre to remove the brown colour given to the acid by carbonaceous matter; the amount of adulteration, he observes, may be readily determined by evaporating a definite weight of the acid in a small capsule of platinum; these impurities however in a medical point of view are immaterial, since they are at once separated by dilution, but in a commercial sense they deserve attention, as their presence considerably increases the specific gravity of the acid. Dr. Ure is of opinion that genuine commercial acid should never exceed 1·8485, and that any density beyond this is the effect of saline combination. Journal of Science and the Arts, No. 7.
ACIDUM SULPHURICUM DILUTUM. L.E.D.
Dilute Sulphuric Acid.
By the dilution of this acid two objects are accomplished,—it is purified, and its dose is more easily apportioned; but it is a circumstance of regret that the strength of this preparation should so materially vary in the different Pharmacopœias.
After the acid is diluted, the sediment ought to be carefully removed, and the water employed for the purpose should be distilled, for although it be in its purest natural state, it will nevertheless contain impregnations capable of affecting the acid. Uses. In addition to the antiseptic and refrigerant virtues which it possesses in common with the other mineral acids, it has astringent properties that render it a most valuable medicine, especially in weakness and relaxation of the digestive organs, in colliquative sweats, in internal hæmorrhagy; in Epistaxis and Hemopthysis it was Sydenham’s favourite remedy; on the same account, when sufficiently dilute, it has been successfully used as a collyrium in the atonic stages of ophthalmia, and as an injection in protracted gonorrhæa. Dose, ♏︎x to xl, the quantity of strong sulphuric acid in any given quantity of the dilute may be found by the Dynameter. To prevent it from injuring the enamel of the teeth it may be sucked through a quill, and the mouth should be carefully washed after each dose. The Infusum Rosæ furnishes an elegant vehicle for its administration. See Form. 40. Officinal Preparations. Acidum Sulphuricum Aromaticum.[[354]] E. Infusum Rosæ. L.
ACIDUM TARTARICUM. L.
Tartaric Acid.
Qualities. Form, Crystals of considerable size, whose primary form is an oblique rhombic prism; they do not deliquesce when exposed to the air, but melt at a heat a little exceeding 212°. Taste, very acid and agreeable. Solubility. Water at 60° dissolves about one-fifth of its weight, and when boiling, a much greater proportion. The solution, which, if saturated, has the specific gravity 1·230, acquires, when diluted, like that of most vegetable acids, a mouldy pellicle by keeping. The saturating power of crystallized tartaric acid is almost exactly equal to that of crystallized citric acid, the atomic weight of the former being 76, and that of the latter 75. Chemical Composition. When uncombined with water, as it exists in tartrate of potass, it is composed of 5 atoms of oxygen, 3 atoms of hydrogen, and 4 atoms of carbon. The crystals consist of 1 atom of acid and 1 of water. Incompatible Substances. Alkalies, Earths, and their carbonates; the salts of lime and lead. The solutions of the salts of potass are converted by it into bi-tartrate, or super-tartrate. Medicinal Uses. It is introduced into the Pharmacopœia as a cheap and efficient substitute for the citric acid. It is also used in the preparation of Sodaic powders, Seidlitz powders, &c. Adulterations. When carelessly prepared it will contain sulphuric acid, to detect which, let a portion be dissolved in distilled water, and a solution of acetate of lead be added. A precipitate will appear which, if the acid be pure, will be entirely redissolved by a few drops of acetic acid, or pure nitric acid. If any portion remain undissolved, sulphuric acid is the cause. Muriate of Baryta also, when sulphuric acid is present, but not otherwise, gives a precipitate insoluble by an excess of muriatic acid.
ACONITI FOLIA. L.E.D. (Aconitum Napellus.[[355]]) Aconite.
Woolfsbane, Monkshood.