ACID

washed with water, and then decomposed by dilute sulphuric acid toform sulphate of lime, which is separated by a filter, and the citricacid crystallized by evaporation. An ounce of this dissolved in apint of water is about equal in strength to lemon juice; soluble incold, but more readily in hot water ; also in alcohol.

Incompatible with the sulphuric and nitric acids, with the acetates oflead and mercury, and the nitrate of mercury.

Medicinally it is antiseptic, antiscorbutic, refreshing, slightly diuretic,and an antidote to narcotic poisons, such as belladonna. Dose from1)^x to ^ss in 31V of water.

The tartaric acid is often sold instead of the citric, as it closely resem-bles it, and is much lower in price.Acidum Formicarum. See Formic Acid.Acidum Hydrociii.oricum. New. See Acidum Muriaticu.m.Acidum Hydrocyanicum. P. Hydrocyanic, or Prussic Acid. Onepart of the strong acid with eight parts and a half by weight or sixparts by volume of water is the medicinal acid. Dr. Ure says, thespecific gravity should be 0-996, or 0-997. It is liquid, colourless,transparent, and has a powerful deleterious odour, like that of bitteralmonds, with a taste at first cooling, but afterwards acrid and irri-tating.

Medicinally it is tonic. Dose from two drops to eight drops of thediluted acid in dyspepsia, phthisis, &c. It is also antispasmodic.As a lotion it is said to be good in impetigo and acne rosacea.

Poisonous, when pure, in very small doses; a single drop put on thetongue of a dog making him fall as if shot; the common acid is poi-sonous in large doses, producing stupor, nausea, dilated pupils, syn-cope, and death, almost instantaneously. Even the vapour hasproved fatal during its preparation.

Antidotes. When it is possible, hot brandy and water, turpentine, orcamphor mixture should be given without delay, along with aroma-tic spirit of ammonia, or any other powerful stimulant.

Tests. The peculiar nutty smell of the acid. Sulphate of iron givesa precipitate of a dark brown colour, which, on adding a little sul-phuric acid, becomes first green and then fine blue. The poison will

frequently be found in the blood as well as in the stomach___

(Sciieklb.)Acidum Muriaticum. L. E. D. Muriatic or Hydrochloric Acid,Spirit of Salt. Procured from common salt by distilling it withsulphuric acid and water over a water bath. It is composed of chlo-rine or oxymuriatic acid gas and hydrogen, according to Sir H. Davy.It is, when pure, usually transparent, but may have a yellow tingewithout being very impure.