Caustic, I′odine. Syn. Causticum iodin′ii, L. Prep. (Lugol.) Iodine and iodide of potassium, of each 1 part; water 2 parts; dissolve. Used in similar cases to iodine paint, and to scrofulous growths and ulcers.

Caustic, Lu′′nar. Syn. La′pis inferna′lis, L. Prep. 1. Nitrate of silver fused and formed into sticks by pouring it into moulds.

2. (E. R. Squibb.) Nitrate of silver fused with a small quantity of chloride of iron, and formed into sticks or points. The chloride of iron gives toughness to the caustic.

Caustic, Mercu′′rial. Syn. Caustic of nitrate of mercury; Causticum ac′idi hydrar′′gyri nitra′tis, C. h. deutronitratis, L. From mercury, 1 part; commercial nitric acid, 2 parts; dissolve.

2. (Cutan. Hosp.) Mercury, 1 part; nitric acid (sp. gr. 1·5), 2 parts.

3. (P. C.) As No. 1, but evaporating the solution to 34ths its weight. These liquids are applied with a pencil or lint, in scrofulous and syphilitic ulcers and eruptions, and in lupus, psoriasis, lepra, and other obstinate skin diseases; but their use requires great care.

4. (With arsenic.—Cutan. Hosp.) Mercury, 12 oz.; nitric acid, 12 oz.; arsenious acid, 12 dr.; as before.

Caustic, Ni′tric. Syn. Solid′ified nitric acid; Causticum ni′tricum, L. Prep. (Dr Rivallie.) Concentrated nitric acid is gradually dropped on a piece of lint, placed in a saucer or glass; as soon as the lint is gelatinised, it is pressed into a suitable shape with a glass rod, and applied to the part; it must be removed in 15 minutes. In cancerous tumours, fungoid growths, &c.

Caustic, O′′piated. Syn. Causticum opia′tum, L. Prep. 1. Common caustic (potassa with lime), 4 dr.; powdered opium, 1 dr.; soft soap, q. s. to make a paste. Applied to fungous ulcers.

Caustic, Plunket’s. Upright crowfoot and lesser spear-wort, of each 1 oz.; sulphur, 5 scrup.; white arsenic (in very fine powder), 1 dr.; beat to a smooth paste, form it into balls, and dry them in the sun. In cancer; a portion of one of the balls is reduced to powder, which is mixed up with yelk of eggs, and applied on a piece of bladder.