Uses.-Iodine is very largely used in medicine. It excites the action of the absorbent and glandular systems, and is employed both internally and externally. TINCTURA IODI. U. S. Tincture of Iodine. A 7 per cent. alcoholic solution of Iodine (see page 369), 6.3 C.c. of the Tincture, mixed with a solution of 2 Gm. of potassium iodide in 25 C.c. of water and a little starch T.S., should require, for complete decoloration, 35 C.c. of the volumetric solution of decinormal sodium hyposulphite (corresponding to about 7 Gm. of iodine in 100 C.c.). LIQUOR IODI COMPOSITUS. U. S. Compound Solution of Iodine. [LUGOL'S SOLUTION.] Old form. oz. av. Metric. 5 Gm. 10 Gm. 1 oz. av. Dissolve the Iodine and Potassium Iodide in a sufficient quantity of Distilled Water to make the product weigh 100 Gm. [or measure, old form, 9 fl. oz.]. Keep the Solution in glass-stoppered bottles. In this Solution iodine is dissolved in water with the assistance of potassium iodide. Iodine dissolves sparingly in water, but freely in a solution of potassium iodide. In using that salt to render iodine more soluble in water, the iodide is generally employed in a quantity twice the weight of the iodine. The Solution contains about 3.25 grains of iodine in the fluidrachm. The official quantitative test requires that 12.66 Gm. of the Solution, mixed with a little gelatinized starch, should require, for complete decoloration, 50 C.c. of the volumetric solution of sodium hyposulphite. Uses. This Solution affords an efficient means of administering iodine internally. It is given in five-minim (0.3 C.c.) doses, and, to prevent gastric irritation, it must be largely diluted. UNGUENTUM IODI. U. S. Iodine Ointment. An ointment containing 4 per cent. of Iodine, 1 per cent. of Potassium Iodide, 2 per cent. of Water, and 93 per cent. of Benzoinated Lard. (See Unguenta, Part VI.) SYRUPUS ACIDI HYDRIODICI. U.S. Syrup of Hydriodic Acid. This is a syrupy liquid containing 1 per cent. of absolute hydriodic acid [HI; 127.53] and having the specific gravity 1.313 (see page 300). It is made by dissolving potassium iodide and potassium hypophosphite in water and decomposing them by adding a solution of tartaric acid in diluted alcohol. Tartaric acid forms with soluble potassium salts acid potassium tartrate (cream of tartar); this is but sparingly soluble in water, and less so in diluted alcohol, and hence is precipitated out. Hydriodic acid is liberated, and dissolves in the aqueous liquid. A little hypophosphorous acid is also liberated by the action of the tartaric acid on the potassium hypophosphite. The reason for placing the mixture in ice-water is to facilitate the crystallization of the acid potassium tartrate by lowering the temperature. The alcohol is used with the same intention. The object of this preparation is to furnish an agreeable mode of administering hydriodic acid, and also a liquid which will be reasonably stable. Hydriodic acid, HI, is easily decomposed in simple aqueous solution, free iodine being liberated, and if taken internally when in this condition, serious results might follow. Syrup of hydriodic acid was formerly made by passing hydrogen sulphide through an alcoholic solution of iodine (see U.S. P. 1880). The chemical reaction which takes place may be expressed as follows: 4I + 2H,S = 4HI + 2S. Uses.-Syrup of hydriodic acid is used as an alterative and antipyretic. The dose is twenty to forty minims (1.2 to 2.4 C.c.). QUESTIONS ON CHAPTER XXXIV. PREPARATIONS OF THE HALOGENS. What is meant by the term "halogen"? What four elements are called "halogens"? Describe chlorine. Give its symbol and molecular weight. What is its specific gravity? What is its most characteristic property? What is its principal use, and how is it generally employed? What is its principal hydrogen compound? What are its compounds with metals and bases termed ? When combined with oxygen, what are its compounds with metals and bases termed? How may chlorides in solution or hydrochloric acid be recognized? How may chlorates be recognized? How is chlorine water recognized? What amount of the gas should it contain? Explain the reaction which takes place in its production. How may its strength be tested? How may excess of hydrochloric acid be detected? How may chlorine water be prepared extemporaneously? What explosive gas is generated at the same time? What does the liquid contain besides chlorine? What are the uses of chlorine water? How may chlorine be conveniently used as a disinfectan What is chlorinated line? Give its Latin name. How much available chlorine should it contain? How is it prepared? What is a popular name for it? Wherein does it differ from the French preparation known as "Eau de Javelle" (Javelle's Water)? Give the symbol and atomic weight of bromine. Where is it obtained, and how is it prepared? What is bittern, and what does it contain? What is the character of the vapor of bromine ? What are the tests for bromine ? How may the presence of iodine be detected? What is its medicinal use? What is "Bibron's antidote" to rattlesnake poison? Give the symbol and atomic weight of iodine. How was it formerly obtained, and how is it now obtained? Explain the reaction which takes place in its production. How soluble is iodine in alcohol? How may the following impurities be detected?-viz.: moisture; iodine chloride; iodine cyanide; more than traces of chlorine or bromine. In what form is its combination with hydrogen official? What are the tests for iodine and the iodides? What is its use in medicine? What is tincture of iodine? How may its strength be tested? How is it used medicinally, and what is the dose? Give the formula for compound solution of iodine. What is the official name and synonyme of compound solution of iodine? How much iodine does a fluidounce of the solution contain? What is the object of using iodide of potassium in this preparation? How much iodine is there in a fluidounce? How is it used medicinally, and what is the dose? What is ointment of iodine? How is syrup of hydriodic acid prepared? How much absolute hydriodic acid does it contain? What is its specific gravity? What are the objects of this preparation? What is the chemical reaction which takes place when hydrosulphuric acid is passed into a solution containing iodine? What is the use of syrup of hydriodic acid, and what is the dose? CHAPTER XXXV. SULPHUR AND PHOSPHORUS. S; 31.98. P; 30.96. THESE two elements furnish many important compounds to medicine. They present several analogies, both physically and chemically. Official Preparations of Sulphur and Phosphorus. Sulphur Sublimatum.-Made by subliming crude sulphur. Sulphur Lotum.-Made by washing sublimed sulphur. Sulphur Præcipitatum.—Made by precipitating a solution of calcium disulphide with HCI. Sulphuris Iodidum -Made by heating iodine with sulphur. Unguentum Sulphuris.-Made by mixing 30 parts of sublimed sulphur with 70 parts of benzoinated lard. Sulphur loosely combined. Hydrogen Sulphide. By acting on ferrous sulphide with diluted sulphuric acid. (See Tests.) Carbonei Disulphidum.-By passing sulphur vapor over red-hot charcoal. Phosphorus.-Made by deoxidizing phosphoric acid with carbon. Oleum Phosphoratum.-Made by dissolving 1 per cent. of phosphorus in almond oil. Pilulæ Phosphori.—Each pill contains of a grain of phosphorus. Unofficial Compounds of Sulphur and Phosphorus. Acidum Hyposulphurosum, H2SO2. Acidum Hypophosphorosum, H3PO2. Acidum Metaphosphoricum, HPO3. Acidum Phosphorosum, H,PO.. Acidum Pyrophosphorosum, H4P207. Sulphur. Add metallic zinc to sulphurous acid contained in a closed vessel. Decompose barium hypophosphite by the aid of sulphuric acid, filter, and evaporate to a syrupy consistence. (See Acidum Hypophosphorosum Dilutum, page 488.) Evaporate a solution of phosphoric acid until the residue ceases to give off water. This solidifies on cooling, and on exposure absorbs moisture and deliquesces. Expose phosphorus to moist air under a bell-jar, Precipitate sodium pyrophosphate with a solution Sulphur is found uncombined in Sicily and in other parts of the world. In the form of sulphates and sulphides it is widely diffused. It is prepared for use by fusing it, allowing it to stand to permit the earthy impurities to settle, and then pouring it into cylindrical moulds. The sulphur in cylinders is termed roll-sulphur. Three forms of sulphur are official,-sublimed, washed, and precipitated sulphur. Sulphur forms with hydrogen an offensive gas, which is known officially as hydrogen sulphide, HS. It is also termed sulphuretted hydrogen and hydrosulphuric acid. The formula for its preparation will be found under "Tests," in Part V. It is used for proving the presence or absence of certain metallic salts, lead, bismuth, antimony, copper, mercury, zinc, etc., with which it produces characteristic precipitates. Sulphides are compounds of elements with sulphur. Some of the sulphides are analogous to acids, others to bases; and these different sulphides, by combining with one another, form compounds, which, from their analogy to salts, are called by Berzelius sulpho-salts. It forms with oxygen two oxides, sulphurous oxide, SO, and sulphuric oxide, SO,. These oxides, by their union with water, form sulphurous acid, H,SO,, and sulphuric acid, H,SO. These are considered in the chapter on inorganic acids. There is also known hyposulphurous acid, H2SO, the corresponding oxide of which is not known, and thiosulphuric acid (frequently known as hyposulphurous acid), H2SO,, and a series of acids, H2S2Ó ̧‚ H¿S ̧Ö¿‚ нSO, and H2SO, known as the thionic series. Sulphurous acid forms with bases salts which are termed sulphites. The salts similarly produced from sulphuric acid are termed sulphates. The sulphates are much more important salts. Pharmaceutically, they have totally different properties. The official sulphites and sulphates will be considered under their respective bases. 69 Tests for Sulphites and Sulphurous Acid. 1. Solution of barium chloride produces with sulphurous acid or a solution of a sulphite, a white precipitate of barium sulphite, which is soluble in hydrochloric acid. 2. If a solution of a sulphite or sulphurous acid be added to diluted sulphuric acid and zinc, hydrogen sulphide gas is liberated. 3. An acid solution of potassium permanganate is decolorized and deoxidized by sulphurous acid. Tests for Sulphates and Sulphuric Acid. 1. A solution of barium chloride produces a white insoluble precipitate of barium sulphate with sulphuric acid or a soluble sulphate. 2. A soluble salt of lead produces a white insoluble precipitate of lead sulphate with sulphuric acid or a soluble sulphate. SULPHUR SUBLIMATUM. U. S. Sublimed Sulphur. S; 31.98. Preparation. When vapors of sulphur are conducted into a chamber properly cooled, they are condensed in the form of a crystalline powder, which collects on the sides and bottom of the chamber. The yellowish powder is known as sublimed sulphur, or flowers of sulphur. It is in the form of a fine, yellow powder, having a slight, characteristic odor, and a faintly acid taste. Insoluble in water; slightly soluble in absolute alcohol; more readily soluble in benzin, benzol, oil of turpentine, and many other oils; also in ether, in chloroform, and in boiling, aqueous solutions of alkaline hydrates. Carbon disulphide promptly dissolves a portion of it, but leaves a residue of crystalline sulphur, which may be dissolved by a boiling solution of an alkaline hydrate. |