(I. Eq. = 127.)

Iodum Purificatum. Purified Iodine. [Iodinium, Iodine. IT. S.] Iodine, in crystals (so named from ίωδηζ, violet).

Prep. Iodine is prepared from kelp, the vitrified ashes of sea-wrack; found in the Western Islands, north of Scotland and Ireland; from the solution of this substance, after the crystallization of most of the salts, as the carbonate of soda, etc, a liquor remains, containing the iodides of sodium, potassium, and magnesium; this, when treated with sulphuric acid and binoxide of manganese, yields iodine, which sublimes, and is collected in receivers; by means of the peroxide of manganese oxygen is set free and replaces the iodine; if we suppose one equivalent of iodide of sodium to be acted on by one of binoxide of manganese and two of sulphuric acid, the formula representing the changes is as follows:

(Na I + Mn O2+2 So3=Na O, So8 + Mn O, So3 + I).

Prop. & Comp. Black scales, or laminar crystals, with metallic lustre, sp. gr. 4.95, odour similar to chlorine, melts when heated, then sublimes in a beautiful violet vapour, soluble in rectified spirits and ether, but slightly so in pure water, about 1/7000 much more soluble in a watery solution of iodide of potassium and chloride of sodium. The aqueous solutions precipitate starch of a dark-blue colour. In free alkaline solutions iodine dissolves and forms salts.

Off. Prep. Linimentum Iodi. Liniment of Iodine. (Iodine, one ounce and a quarter; iodide of potassium, half an ounce; rectified spirit, five fluid ounces.)

[Liquor Iodinii Compositus. Compound Solution of Iodine. Lugol's Solution of Iodine. Iodine, 360 grains; iodide of potassium, 720 grains; distilled water, a pint.]

Tinctura Iodi. Tincture of Iodine. (Iodine, half an ouuce: iodide of potassium, a quarter of an ounce; rectified spirit, twenty fluid ounces.)

[Tinctura Iodini. Tincture of Iodine. Iodine, a troy ounce; alcohol, a pint. U. S.]

[Tinctura Iodinii Composita. Compound Tincture of Iodine. Iodine, half a troy ounce; iodide of potassium, a troy ounce; alcohol, a pint. U. S.]

Unguentum Iodi Compositum. Compound Ointment of Iodine. (Iodine, thirty-two grains; iodide of potassium, thirty-two grains; proof spirit, one fluid drachm; prepared lard, two ounces.)

[Unguentum Iodinii. Ointment of Iodine. Iodine, twenty grains; iodide of potassium, four grains; water, six minims; lard, a troy ounce. U. S.]

[Unguentum Iodinii Compositum. Compound Ointment of Iodine. Iodine, fifteen grains; iodide of potassium, thirty grains; water, thirty minims; lard, a troy ounce. U. S.]

Therapeutics. When applied externally, free iodine acts as an irritant, or vesicant, according to the mode of using it; and when rubbed in for some time, it is absorbed, and influences the neighbouring parts, and also the system at large: when the diluted vapour is inhaled, it acts topically on the mucous membranes of the respiratory passages. Internally, free iodine produces irritation of the mucous membrane of the alimentary canal, causing, in large doses, heat and pain at the epigastrium, and vomiting; and, when the full influence of iodine upon the system is desirable, the drug is usually given in combination, more especially as iodide of potassium, which produces but little local irritation. Iodine is rapidly absorbed into the blood, and can be detected in many of the fluids soon after administration, especially in the urine; the constitutional effects produced are increased activity of most of the secreting and excreting organs, as the kidneys, mucous membranes, and skin; it also powerfully influences the glandular and absorbent systems, as seen when such parts are enlarged, as in bronchocele, and in scrofulous glands of the neck and abdomen. It is stated occasionally to cause the wasting of even healthy glands, as the breasts and testes; it has a powerful alterative action, as exhibited in its influence over scrofulous affections and secondary syphilitic disease. When given in large medicinal doses, the mucous membrane of the nose, frontal sinus, eyes, pharynx, etc, often become irritated, and catarrhal symptoms, coryza, etc, are induced; occasionally much depression ensues from its administration, accompanied by a low febrile state of system.

Iodine or iodide of potassium is administered in very many diseases, as the different forms of scrofula, in bronchocele and other glandular enlargements, in hypertrophy and induration, of organs or other structures, produced by inflammation, as in hypertrophy of the spleen, liver, or uterus, in nodes, etc.; in chronic skin affections, syphilitic or not; for the relief of other secondary or tertiary symptoms, and also in chronic rheumatism; in dropsies as a diuretic; in some forms of amenorrhoea, as an emmenagogue; and in various obstinate mucous discharges, as leucorrhoea, as an alterative.

Externally iodine is used in chronic skin diseases and over enlarged and indurated parts and diseased joints, to alter action or cause absorption; for this purpose it may be applied in the form of the liniment, tincture, or ointment. As a speedy vesicant, the liniment may be painted over the part two or three times; one application, however, is often sufficient. A few drops of the tincture, put into half a pint of hot water, may be used as an inhalation in some forms of chronic bronchitis and phthisis.

Dose. Of iodine (free) 1/2 gr., gradually increased; of tinct. iodi., 5 to 20 minims; of iodide of potassium, vide Potassii Iodidum. [The compound tincture of iodine, U. S., may be given in doses of from 10 to 30 drops, largely diluted, and repeated two or three times a day. The compound solution, 5 to 15 minims in water three times a day.]

Adulteration. Water is often present, also iodide of cyanogen; besides these, fixed impurities, as plumbago, black oxide of manganese, charcoal, iron, etc. The first two are volatile; water can be detected by finding whether bibulous paper is moistened by the iodine; iodide of cyanogen by distilling at a very low temperature, when this body sublimes, if present, in white crystalline needles before the iodine; the fixed impurities are left after sublimation. The Pharmacopoeia gives the following quantitative test: 12.7 grains, dissolved in an ounce of water containing 15 grains of iodide of potassium, require for complete decoloration 100 measures of the volumetric solution of hyposulphite of soda. In this process, iodide of sodium (Na I), which is colourless, and also tetrathionate of soda (Na O, S4 O5), are formed. The following formula will serve to illustrate the changes which ensue, 2 (Na O, S2 O2) + I=Na I, + Na O, S4 O5; the amount of iodine can thus be estimated, 100 measures of the volumetric solution corresponding to 12.7 grains of iodine.

Sulphuris Iodidum. Iodide Of Sulphur. (Not Officinal.) [Officinal. U.S.]

Prep. (Sulphur, one ounce; iodine, four ounces. Put the sulphur in a glass vessel, and place on it the iodine; hold the vessel immersed in boiling water until they have united; afterwards, when cool, the vessel being broken, break the iodide into fragments, and keep in a well-stoppered vessel.)

Prop. & Comp. A bluish black crystalline metallic-looking substance, not unlike sulphuret of antimony in appearance, having the odour of iodine, it stains the skin yellow, is decomposed by boiling in water, and, if properly prepared, should give, when so boiled, 20 per cent. residue of sulphur. Composition (Is2) or a bisulphuret of iodine.

Therapeutics. Applied externally in the form of an ointment of the strength of about thirty grains of the salt to an ounce of lard, it acts in a manner very similar to iodine, and has been employed in some obstinate chronic skin diseases, as lepra, porrigo, acne indurata, etc. Internally it possesses no particular value, but has been given as an alterative.

Dose. Half gr. to 3 gr. or more.