Potassii Bromidum - Potassii Bromidi - Potassium Bromide (U. S. P.).

Origin. - Prepared by adding bromine to a solution of potassa, evaporating to dryaess, mixing with charcoal, heating to redness, dissolving in water, and crystallizing. It should contain not less than 97 per cent. of pure potassium bromide.

Description and Properties. - Colorless or white cubical crystals or granules, odorless, with a pungent, saline taste; permanent in air; soluble in about 1.5 parts of water and in 180 parts of alcohol at 250 C.

Dose. - 5-60 grains (0.3-4.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Sodii Bromidum - Sodii Bromidi - Sodium Bromide (U. S. P.). - Origin. -Obtained from a solution of soda in the same manner as potassium bromide. It should contain when dried not less than 97 per cent. of pure sodium bromide.

Description and Properties. - Colorless or white cubical crystals, or a white granular powder, odorless, and with a saline, slightly bitter taste. From air the salt abstracts moisture without deliquescing. Soluble in 1.7 parts of water and in 12.5 parts of alcohol at 250 C. It should be kept in well-stoppered bottles.

Dose. - 10-60 grains (0.6-4.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Ammonii Bromidum - Ammonii Bromidi - Ammonium Bromide (U. S. P.). - Origin. - Obtained by neutralizing hydrobromic acid with ammonia or ammonium carbonate, evaporating, and crystallizing. It should contain not less than 97 per cent. of pure ammonium bromide.

Description and Properties. - Colorless, transparent, prismatic crystals, or a white crystalline powder, odorless, and of a pungent, saline taste; permanent in the air. Soluble in 1.2 parts of water and in 12.5 parts of alcohol at 250 C.

Dose. - 5-30 grains (0.3-2.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Lithii Bromidum - Lithii Bromidi- Lithium Bromide (U. S. P.). - Origin. -Prepared by a solution of ferrous bromide and lithium carbonate, the cool liquid being evaporated and crystallized. It should contain when well dried not less than 97 per cent. of pure lithium bromide.

Description and Properties. - A white granular salt, odorless, and having a sharp, slightly bitter taste; very deliquescent. Soluble in 0.6 part of water and very soluble in alcohol. It should be kept in well-stoppered bottles.

Dose. - 5-20 grains (0.3-1.2 Gm.) [15 grains (I Gm.), U. S. P.].

Calcii Bromidum - Calcii Bromidi - Calcium Bromide (U. S. P.). - Origin. -Prepared by dissolving pure calcium carbonate in hydrobromic acid and evaporating. It should contain not less than 97 per cent. of pure calcium bromide.

Description and Properties. - A white granular salt, odorless, of a sharp, saline taste, and very deliquescent. Soluble in 0.5 part of water and in 1 part of alcohol at 25 C. It should be kept in well-stoppered bottles.

Dose. - 10-30 grains (0.6-2.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Zinci Bromidum - Zinci Bromidi - Zinc Bromide (U. S. P.). - Origin. - Prepared by digesting granulated zinc in hydrobromic acid, concentrating the solution, acidulating with hydrobromic acid, and drying upon a water-bath. It should contain when anhydrous not less than 97 per cent. of pure zinc bromide.

Description and Properties. - A white granular powder, odorless, and having a sharp, saline, and metallic taste. Very deliquescent. Readily souble in water and alcohol.

Dose. - 1-5 grains (0.06-0.3 Gm.) [2 grains (0.025 Gm.), U. S. P.].

Strointii Bromidum - Strontii Bromidi - Strontium Bromide (U. S. P.). Origin. - Obtained by neutralizing hydrobromic acid with strontium carbonate, filtration, and evaporation. It should contain not less that 97 per cent. of pure strontium bromide.

Description and Properties. - Colorless, transparent, hexagonal crystals, odorless, and having a bitter, saline taste. Very deliquescent. Soluble in 1 part of water and readily soluble in alcohol.

Dose. - 5-30 grains (0.3-2.0 Gm.) [15 grains (1 Gm.), U. S. P.].

Acidum Hydrobromicum Dilutum - Acidi Hydrobromici Diluti - Diluted Hydrobromic Acid (U. S. P.). - Definition. - A liquid composed of not less than 10 per cent. by weight of absolute hydrobromic acid and 90 per cent. of water.

Description and Properties. - A clear, colorless liquid, odorless, and having a strongly acid taste. Miscible in all proportions with water and alcohol. It should be kept in glass-stoppered bottles, protected from light.

Dose. - 20 minims to 2 fluidrachms (1.23-7.39 Cc.) [1 drachm (4 Cc), U. S. P.].

Bromoformum - Bromoformi - Bromoform (U. S. P.). - Definition. - A liquid consisting of 99 per cent. by weight of absolute bromoform (CHBr3), and 1 per cent. of absolute alcohol.

Obtained by the action of bromine upon equal parts of methylic alcohol and caustic potash.

Description and Properties. - A heavy, transparent, colorless, mobile liquid having an ethereal odor and a penetrating, sweetish taste resembling chloroform. It is only slightly soluble in water, but readily in alcohol and ether. Specific gravity at 25o C, 2.808. It is only slightly volatile at ordinary temperature, boils at I480 C.,and solidifies at 6 C.

Absolute bromoform is decomposed in presence of light and air more rapidly than chloroform. The addition of 4 per cent. of alcohol, as in the case of chloroform, will preserve bromoform for months. When decomposed, bromine is set free, which colors the liquid yellowish red.

Dose. - 1-5 minims (0.06-0.3 Cc).

Antagonists and Incompatibles. - The bromides are antagonized by the motor excitants and muscle stimulants. The incompatibles are acids, acidulous and metallic salts. Spirit of nitrous ether is incompatible with the ammonium bromide.

Synergists. - Their action upon the brain is enhanced by opium and the hypnotics, while the cardiac depressants increase the effect of potassium bromide upon the circulatory system.

Physiological Action. - The action of the bromides depends upon both ions found in the salt, since practically all are dissociable. Thus each bromide salt shows a certain amount of variation in its reaction. The action of the bromine ion is distinctive, however. The actions of the Na, K, NH4, Li, Zn, and Sr ions are also distinctive and obey the general laws of the inorganic salts. Potassium bromide being the most widely employed, its action will be considered in detail first.