BROMIDE OF POTASSIUM.

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and tlieir neutrality with respect to litmus and turmeric. A solution ofthis salt should give no precipitate with chloride of barium, shewing theabsence of carbonates and sulphates. The method employed by Rose(. Journ. de Pharm. t. 23, p. 489) for detecting minute quantities of thechlorides in bromides, is the following :—If pure bromide of potassiummixed with excess of bichromate of potash be distilled with concentratedsulphuric acid in a tubulated retort, to which is adapted a receiver con-taining excess of solution of caustic ammonia, pure brome distils over, andthe ammoniacal liquor remains perfectly colourless. But if the bromidecontained a chloride, both brome and the chromate of chloride ofchromium distil over, and the ammoniacal liquor becomes yellow:chromic acid may be detected in the solution by the usual tests.

Physiological Effects. —(a.) On vegetables. —The effects on plantshave not been ascertained.

(b.) On animals. —Thirteen grains of bromide of potassium dissolved inwater, and injected into the jugular vein of a dog, coagulated the blood,caused convulsions and death in a few minutes (Barthez, Journ. de Chim.Med. t. 5 me . p. 214). The same experimenter introduced a drachm ofthe salt into the stomach of a dog without any ill effects, save vomiting.But two drachms, and even a drachm and a half, killed dogs in threedays, when retained in the stomach by a ligature of the gullet, withmarks of inflammation in the gastro-intestinal membrane. Maillet {Journ.de Chim. Med. t. 3, 2 e . Serie, p. 225) gave two ounces to a dog withoutanv ill effect; and he observes, that according to the principle, that thedose of a saline substance for the horse should be eight times that for thedog, a pound of bromide of potassium would have no ill effect onhorses.

(c.) On man. —The effects of bromide of potassium on man requirefurther investigation. They appear to be analogous to those of iodide ofpotassium. Dr. Williams ( Elements of Medicine, vol. i. p. 338) gave fivegrains of this salt three times daily for fourteen months, without anyinjurious effect.

In most cases it acts as a diuretic. In irritable conditions of the ali-mentary tube it is apt to occasion diarrhoea. Three cases are mentioned byDr. Williams, in which, on account of this state of the bowels, more thanfour or five grains could not be exhibited at a time, and even then it wasoccasionally necessary to give opium. Under the continued use of it,enlargements of the spleen and liver, and swellings of the lymphaticglands, have disappeared ; so that it appears to agree with iodine, mer-cury, and the alkalies, in exercising that kind of influence over the nutri-tion of the body which has been designated by the terms resolvent,alterative, and deobstruent. Dr. Williams thinks that it possesses“ unusual, if not specific, powers in the cure of diseases of the spleen.”

Uses. —In 1828, Pourclie {Journ. de Chim. Med. tom. iv. p. 594) em-ployed this saltwdth benefit in the treatment of broncliocele and scrofula:it was taken internally, and applied externally in the form of ointment.In 1836 it was introduced into the London Pharmacopoeia, in conse-quence of the great success obtained from the use of it in a case ofenlarged spleen, under the care of Dr. Williams {op. cit.) In this, andin three other successful cases of the same disease, it was used internallyonly. Dr. Williams also gave it with success in a case of ascites. Ma-gendie {Formulaire, 8 m °. cd. 1835) employs it as an anti-scrofulous remedy,