Lond. Creasote.1

This substance, now introduced into the list of Materia Medica of the London College, is prepared from the oil of wood tar. Carbonate of potassa is first added to the oil, to free it from some acetic acid; after which the acetate is separated by distillation. Some phosphoric acid is then added to the product to neutralize ammonia, and it is distilled a second time. What comes over is mixed with a strong solution of potassa, which combines with the creasote : this compound is then neutralized by sulphuric acid, and the oil which separates, after being distilled, is impure creasote. It is purified by repeatedly treating it with potassa, and as frequently redistilling.

Qualities.-Creasote, when pure, is a colourless limpid liquid, having a sp. gr. of 1.037. It has a hot pungent taste, which leaves a degree of sweetness on the palate: its colour resembles that of impure pyroligneous acid, or smoked meat. It is soluble in 80 parts of water : and in every proportion in alcohol and ether. It unites with chlorine, iodine, bromine, sulphur, the alkalies, and the earths; but the latter compounds are decomposed by weak acids. It is a compound of carbon, hydrogen, and oxygen in unknown proportions.

Medical properties and uses.-Creasote is a powerful stimulant. In large doses it is destructive to animal life; and even its aqueous solution kills fish, insects, and plants. It has been administered, internally, in cases of anorexia, and affections of the stomach depending on atony of the organ, but its chief value consists in its powerful influence in relieving rheumatic and neuralgic pains, when it is externally applied. It has also been used with advantage pinorrigo scutulata.

The dose is from vj. to xv. in a glassful of water, or any bitter aqueous infusion.