Bromides

Bromides.—Bromine combines very rapidly with most of the metals, occasionally so as to cause ignition, as in the case of antimony, and forms a class of salts usually known as bromides, though perhaps they are rather hydrobromides (see HYDROBROMIC ACID). Bromide of silver, which is very sensitive to the sun's rays, is used in photography. Bromide of potassium, which is the most important of the bromides, may be prepared by the action of bromine on solution of caustic potash. The whole is then evaporated to dryness, and ignited along with charcoal. On solution in water and crystallisation, the bromide is obtained in colourless, cubical crystals, possessing a pungent saline taste, and which are very soluble in water. This salt has been used in a very large number of diseases, owing to its powerful sedative properties. Other bromides (such as those of sodium and lithium) are of comparatively little importance, although they possess similar medicinal properties. Hydrobromic acid combines with these the tonic effects of hydrochloric acid. In epilepsy, bromide of potassium affords marked relief. As a sedative in nervous excitement and sleeplessness, its use produces beneficial results, while in delirium tremens and tetanus large doses give relief. In excessively large doses, general depression, lowering of the temperature, and even death may result. And it should be known and remembered that the administration of bromine compounds in large doses and for long periods often leads to unpleasant effects, collectively termed bromism. The earliest and most common are skin eruptions, resembling Acne (q.v.) or boils; the further results are due to diminished activity of the nervous system—viz. lassitude, low spirits, weakened brain power, &c. All these symptoms soon disappear when the use of the drug is discontinued.