Iodine. Iodinium. A simple body, obtained chiefly from incinerated Sea-weed, or Kelp. It exists

* Ann. de Therap., 1857, p. 205. Journ. de Chim. Med., 1853. Edin. Med. Surg. Journ., lviii. p. 538.

§ Med. Gaz., Aug. 1836. || Braithwaite's Retrospect, xxxiv. p. 178.

largely in many marine plants. It was discovered by M. Curtois, in 1812. Eq. Wt. 127. Soluble in Alcohol and Ether. Soluble in 7000 parts of water. Much more soluble in a watery solution of Iodide of Potassium or of Chloride of Sodium.

Med. Prop. and Action. Iodine, given internally in small or medicinal doses, is tonic and alterative. One of the first and most important effects of this remedy observed by Lugol* is a great increase of appetite. This is certainly one of its best effects; for not only does it indicate an improved state of the digestive organs, but it enables us with ease to invigorate the constitution by wholesome and sufficient nourishment. Together with increased appetite, the general health improves, and the body gains strength and plumpness. There is also increased activity of most of the excreting and secreting organs. The urine is generally much increased in quantity. Some experience this effect so instantaneously, that Iodine has been detected in the urine almost immediately after the dose has been taken; indeed, Prof. Porta observes, that after inhaling the vapour of Iodine for one minute, not so much as a grain of the metal having been lost, his urine gave forth the odour of Iodine for four or five days. It occasionally causes purging, in which case it should be discontinued. In large doses, it produces irritation of the gastro-intestinal mucous membrane, causing pain and heat of the epigastrium and vomiting. When combined with potassium, it does not produce the same amount of local irritation. Some persons, from idiosyncrasy, are unable to take Iodine, even in small doses, without its causing headache, vertigo, coryza, derangement of the digestive organs, &c. This state is designated lodimn; it only remains as long as the patient is taking the remedy; on its being discontinued, the whole of the symptoms disappear. The subject of Iodism has been examined by M. Rilliet, whose observations, though highly interesting, are too lengthy for insertion in this place. Externally applied, it produces intense local action, and often causes a prolonged sensation of pricking and smarting. The skin, when rubbed with it, becomes of a reddish yellow colour, from the absorption of the remedy, its presence in the cutaneous tissue, and its injection into the capillary vessels. The epidermis soon becomes detached in layers of various sizes. When applied to ulcerated surfaces, it at first causes much pain; but as the healing process progresses, the Iodine causes less and less irritation. This diminution of pain was not uniformly observable. When the vapour is inhaled, it excites cough and irritation of the air-passages. Whether inhaled, or applied endermically, it becomes absorbed into the system, and evidences its presence in the urine, on the addition of starch. It has been deemed emmenagogue. Iodine has lately been proposed as a deodorizer and disinfectant by Dr. B. W. Richardson. Air charged with organic impurities is rendered entirely inodorous by the volatilization of Iodine in the apartment.

Offic. Prep. 1. Linimentum Iodi (Iodine oz. 1 1/4; Iodide of Potassium oz. as.; Rectified Spirit fl. oz. v.). This Liniment acts as a speedy vesicant. One to three applications with a camel's-hair brush are usually sufficient.