Fatal Dose.—One fluid drachm of the tincture has proved fatal; recovery has taken place after taking one fluid ounce of the tincture.
Treatment.—The stomach should be emptied by the aid of the stomach pump, and then diluent drinks—arrowroot and barley water—may be given.
Chemical Analysis.—Add bisulphide of carbon to the suspected mixture, and shake them together. The sulphide will dissolve out the iodine, which may be obtained on evaporation and sublimed. The characteristic reaction of iodine, the development of a blue colour on the addition of a small quantity of starch, will be conclusive evidence of its presence. If chloroform be added to iodine in aqueous solution and shaken up, the chloroform is coloured crimson by the iodine, and falls to the bottom as the mixture is allowed to settle.
IODIDE OF POTASSIUM
This salt is largely used in medicine; and though poisonous effects may be produced, due probably to some constitutional idiosyncrasy, it has seldom been used as a poison. It must, however, be placed among noxious irritant substances.
General Characters.—Iodide of potassium—hydriodate of potash—occurs in cubical crystals of a white or faint yellow colour, very slightly deliquescent when pure, and with a feeble odour of iodine.
Symptoms.—Iodide of potassium acts as an irritant in large doses, producing also many of the symptoms which attend a violent catarrh, with profuse discharge from the nose, lachrymation, and swelling of the eyelids, also pustular eruptions like acne on the face and body generally. Small doses—three to five grains—have produced in some persons most unpleasant and even alarming symptoms. In chronic poisoning, certain glands, the mammary and testicles, are said to waste away. Salivation is not infrequently present. I have seen the administration of the salt produce a severe bullous and hæmorrhagic eruption, simulating hæmorrhagic smallpox, with sloughing. (See also the account in British Medical Journal, 1878, of a case of purpura in a child five months old, after a dose of two and a half grains of the salt.)
Treatment.—The use of emetics and the stomach pump, starch, &c.
Chemical Analysis.—In solution, iodide of potash gives the following characteristic reactions:
| 1. With a salt of lead | Bright yellow precipitate. |
| 2. With corrosive sublimate | Bright scarlet precipitate. |
| 3. With strong nitric acid and starch | A blue colour. |