CHARACTERS.-It is a colorless gas possessing a slight characteristic odor and a somewhat sweet taste. Solubility.—Quite soluble in water at low temperatures; I volume of water dissolves 1.3 volumes of Nitrous Oxide at 25°C. (77°F.).

IMPURITIES.-Carbon dioxide, halogens, acids, bases, reducing substances. For the Therapeutics of Nitrogen Monoxide see p. 788.

III. AQUA.—Water. H2O=18.016.-Potable water in its purest attainable state.

CHARACTERS.-A colorless, limpid liquid, practically tasteless and odorless. When heated nearly to the boiling point and agitated, no disagreeable odor is evolved.

IMFURITIES. Soluble salts, lead, copper, iron, sulphates, chlorides, nitrates, nitrites, ammonium compounds and organic or other oxidizable substances.

IV. AQUA DESTILLATA.-Distilled water. Abv.-Aq. Dest. SOURCE.-Take 1000 volumes of water, distil from a suitable apparatus provided with a block tin or glass condenser, reject the first 100 volumes, which contain volatile impurities, and preserve the next 750 in glass-stoppered bottles, rinsed with hot distilled water immediately before being filled.

CHARACTERS.-A colorless, limpid liquid, without odor or taste, and neutral to the official indicators.

TESTS.-When 100 mils are evaporated on a water bath to dryness, not more than 0.001 of residue should remain. On heating to boiling 100 mils acidulated with 10 mils of diluted sulphuric acid, and adding 0.1 mil of tenth-normal potassium permanganate volumetric solution, the color of the liquid should not be completely destroyed by boiling for ten minutes, nor by afterwards setting the vessel aside, well covered, for ten minutes (absence of organic or other oxidizable substances). Not the slightest turbidity should result upon the addition to separate portions, of barium chloride test solution (sulphate), silver nitrate t.s. (chloride), ammonium oxalate t.s. (calcium) hydrogen sulphide, t.s., or sodium sulphide, t.s. (metals); nor should its transparency be affected when it is mixed with twice its volume of calcium hydroxide t.s. (absence of carbon dioxide). It shows no deep yellow, orange or brown coloration when I mil of Nessler's reagent is added to 100 mils of the water (ammonia).

V. AQUA DESTILLATA Abv.-Aq. Dest. Steril.

STERILISATA.-Sterilized Distilled Water.

SOURCE.-Transfer the necessary quantity of freshly distilled water to a flask of hard glass of sufficient size which has been previously cleansed and sterilized. Close the mouth of the flask with pledget of sterilized purified cotton, boil for thirty minutes and allow the water to cool without removing the plug. Finally protect the mouth of the flask and the cotton pledget by wrapping the top of the flask tightly with paper.

Sterilized distilled water should be used within forty-eight hours after its preparation.

Distilled Water or the Sterilized Distilled Water should always be used for making up prescriptions.

For the Therapeutics of Water see p. 564.

VI. LIQUOR HYDROGENII DIOXIDI.-Solution of Hydorgen Dioxide Abv.-Liq. Hydrog. Diox. An aqueous solution of Hydrogen Dioxide (H2O2 =34.02), which should contain, when freshly prepared, about 3 per cent., by weight of Hydrogen Dioxide, corresponding to about 10 volumes of available Oxygen. Upon removing the stopper from the bottle, not more than a slight pressure should be observed.

SOURCE.-A solution of Barium Dioxide, 300, in cold distilled water, 500, refrigerated to below 10°C. (50°F.), is thoroughly mixed with the greater part of a cool solution of Phosphoric Acid, 96, in distilled water, 320; a certain portion of the latter solution being reserved to add from time to time to the liquid to render it acid whenever its reaction has become alkaline. BaO2+2H3PO1 =Ba(H2PO4)2+H2O2. Filter, and wash with distilled water. Add Diluted Sulphuric Acid to the filtrate, and starch, 10; by agitation. Filter and re-filter until a clear solution is obtained.

CHARACTERS.-A colorless liquid, odorless or having an odor suggesting ozone, slightly acid to the taste, and producing a peculiar sensation and froth in the mouth; prone to deteriorate upon keeping, or upon protracted agitation, and rapidly decomposed by many oxidizing as well as reducing substances. If the stopper in the bottle is coated with paraffin or replaced by a pledget of purified cotton, deterioration is retarded.

IMPURITIES.-Free acids, arsenic, heavy metals, barium, hydrofluoric acid. Dose, 4 mils (1 fl. dr.).

For the Therapeutics of Hydrogen Dioxide see p. 325.

GROUP III

Sulphur

S=32.07

1. SULPHUR SUBLIMATUM.-Sublimed Sulphur. Abv.-Sulphur. Sublim. Synonym.-Flowers of Sulphur. It should contain not less than 99.5 per cent. of Sulphur.

SOURCE. From Crude Sulphur by sublimation.

CHARACTERS.-A fine, yellow powder, having a slight, characteristic odor and a faintly acid taste. Solubility.-Practically insoluble in water; soluble or partially soluble in carbon disulphide, nearly insoluble in alcohol, chloroform or olive oil; nearly soluble in Ether.

Dose, 4 gm. (60 gr.).

Preparation

Unguentum Sulphuris.-Sulphur Ointment. Sublimed Sulphur, 150; Benzoinated Lard, 850.

2. SULPHUR PRÆCIPITATUM.-Precipitated Sulphur. Abv.-Sulphur Præc. Synonym.-Milk of Sulphur. It should contain, when dried, not less than 99.5 per cent. of Sulphur.

SOURCE. Boil Sublimed Sulphur, 100; with Calcium Oxide, 50; in water. 6S+3CaO = 2CaS+CaS2O3. This gives a solution containing Calcium Sulphide and Calcium Thiosulphate. To it Hydrochloric Acid is added, and Sulphur is thrown down as a very fine precipitate. 2CaS2+CaS2O3+6HCl=3CaCl2+ 6S+3H2O. Wash and dry the precipitate.

CHARACTERS. A fine, amorphous powder of a pale yellow color, without odor or taste.

IMPURITIES.-Arsenic, acids, alkalies.

Dose, 4 gm. (60 gr.).

3. SULPHUR LOTUM.-Washed Sulphur. Abv.-Sulphur. Lot. It should contain, when dried, not less than 99.5 per cent. of Sulphur.

SOURCE.-Sublimed Sulphur, 100; with water, 100; and Ammonia Water, 10; is digested for three days, when water, 100, is added, the mixture strained, and the Sulphur washed with water. It is then drained, and the residue strongly pressed, dried, and passed through a sieve.

CHARACTERS.-A fine, yellow powder, without odor or taste.

IMPURITIES.—Acids, alkalies, arsenic, ammonia, earthy and metallic impurities. Dose, 4 gm. (60 gr.).

Washed Sulphur is contained in Pulvis Glycyrrhizæ Compositus.

For the Therapeutics of Sulphur see p. 327.

4. CALCII SULPHIDUM CRUDUM.-Crude Calcium Sulphide. Synonym.— Sulphurated Lime. A mixture containing not less than 55 per cent. of Calcium Sulphide (CaS=72.14).

SOURCE. Obtained by heating a mixture of Exsiccated Calcium Sulphate, 70; Charcoal, 10; and Starch, 2.

CHARACTERS. A pale gray or yellowish powder, having a faint odor of hydrogen sulphide, and a nauseous, and alkaline taste, and gradually decomposed by exposure to moist air. Solubility.-Very slightly in cold water; more readily in boiling water, which partially decomposes it; readily dissolved by solutions of ammonium salts; insoluble in Alcohol.

Dose, 0.06 gm. = 60 milligm. (1 gr.).

5. POTASSA SULPHURATA.-Sulphurated Potassa. Abv.-Pot. Sulphurat. Synonym. Liver of Sulphur. A mixture composed chiefly of Potassium Polysulphides and Potassium Thiosulphate and containing an amount of sulphides corresponding to not less than 12.8 per cent. of Sulphur.

SOURCE.-By fusing Sublimed Sulphur and Potassium Carbonate.

CHARACTERS.-In irregular pieces, liver-brown when freshly made, changing to greenish-yellow and finally to gray through absorption of moisture, oxygen and carbon dioxide from the air. It has a strong odor of Hydrogen Sulphide and a bitter, acrid, and alkaline taste. Solubility.-Very soluble in water, usually leaving a slight residue. Alcohol dissolves only the sulphides.

For the Therapeutics of Crude Calcium Sulphide and Sulphurated Potassa see

p. 331.

GROUP IV

Phosphorus, Arsenic, Antimony

I. PHOSPHORUS (Abv.—Phosphor.)

P = 31.04

Phosphorus must be carefully preserved under water, in strong, well-closed containers, in a secure and moderately cool place, protected from light.

SOURCE.—Treat Calcium Phosphate with Sulphuric Acid, filter and evaporate. Ca3(PO4)2+2H2SO4 = CaH1(PO4)2+2CaSO4. Heat the Acid Calcium Phosphate thus formed with Charcoal, which first forms Calcium Metaphosphate. CaH4(PO4)2 = Ca(PO3)2+2H2O. This is acted on by the Charcoal thus: 2 Ca(PO3)2+5C2CaO+5CO2+2P2.

CHARACTERS.-A translucent, nearly colorless solid, of a waxy lustre, having, at ordinary temperatures, about the consistence of beeswax. By long keeping the surface becomes white or red, and occasionally black. It has a distinctive and disagreeable odor and taste but should not be tasted, except in a very dilute solution. When exposed to the air it emits white fumes, which are luminous in the dark, and have an odor somewhat resembling garlic; on longer exposure to air, it often takes fire spontaneously. Heated with Hydrogen, it becomes red, amorphous, non-poisonous Phosphorus. Sp. gr., 1.830 at 10°C. (50°F.). Solubility.—In 0.9 part of Carbon Disulphide; in about 17 parts of Chloroform, 102 parts of Absolute Ether, 31.5 parts of Benzene, and 400 parts of Dehydrated Alcohol; sparingly in fixed oils; almost insoluble in water, to which it imparts its characteristic odor and taste.

IMPURITIES.-Arsenic, sulphur.

INCOMPATIBLES.-All oxidizers, as potassium chlorate and permanganate, chlorine, hydrochloric acid, etc.

Pilulæ Phosphori.-Pills of Phosphorus. Abv.-Pil. Phosphor. Add Phosphorus, .06, dissolved in Chloroform, 5, to a mixture of Althea, 6, and Acacia, 3; then add a sufficient quantity of a mixture of Glycerin, 2 volumes, and water, 1 volume, to make 100 pills. Finally the pills are coated with a solution of Balsam of Tolu, 10 gm., in Ether, 15 mils. Strength. Each pill contains 0.0006 gm. (100 gr.) of Phosphorus. Dose, I pill.

For the Therapeutics of Phosphorus see p. 791.

1. CALCII HYPOPHOSPHIS.-Calcium Hypophosphite. Abv.-Calc. Hypophos. Ca(PH2O2)2=170.18. It should contain not less than 98 per cent. of Calcium Hypophosphite. Caution should be observed in dispensing this and other hypophosphites, as an explosion is liable to occur when they are triturated or heated with nitrates, chlorates, or other oxidizing agents.

SOURCE.-Heat Phosphorus with Milk of Lime. Then pass Carbon Dioxide through the liquid to remove the excess of Lime. The Hypophosphite crystallizes out of the solution. 3Ca(OH)2+4P2+6H2O=3Ca(PH2O2)2+2PH3.

CHARACTERS.-Colorless, transparent, monoclinic prisms, or small, lustrous scales, or a white, crystalline powder, odorless and having a nauseous, bitter taste; permanent in the air. Solubility.-In 6.5 parts of water; insoluble in Alcohol. IMPURITIES.-Calcium phosphate and sulphate, arsenic, heavy metals. INCOMPATIBLES.-Arsenic salts, bromine and bromates, chlorine and chlorates, chromates, copper salts, ferric salts, iodine and iodates, nitric acid, permanganates, phosphates, sulphuric and sulphurous acids. The same incompatibles apply to the other Hypophosphites and to Hypophosphorous acid.

It is used to prepare Syrupus Hypophosphitum.
Dose, 0.500 gm. = 500 milligm. (8 gr.).

2. POTASSII HYPOPHOSPHIS.-Potassium Hypophosphite. Abv.—Pot. Hypophos. KPH2O2=104.16. It should contain not less than 98 per cent. of Potassium Hypophosphite.

SOURCE. From double decomposition of Calcium Hypophosphite and Potassium Carbonate; the Potassium Hypophosphite remains in solution. Ca(PH2O2)2 +K2CO3 = CaCO3+2 KPH2O2.

CHARACTERS.-White, opaque, hexagonal plates, or crystalline masses, or a granular powder; odorless, and having a pungent, saline taste. Very deliquesSolubility. In 0.6 part of water and 9 parts of Alcohol; in 0.4 part of boiling water and 5 parts of boiling Alcohol; insoluble in Ether.

cent.

It is used to prepare Syrupus Hypophosphitum.

Dose, 0.500 gm. = 500 milligm. (8 gr.).

3. SODII HYPOPHOSPHIS.—Sodium Hypophosphite. Abv.-Sod. Hypophos. NaPH2O2+H2O=106.07.. It should contain not less than 98 per cent. of Sodium Hypophosphite.

SOURCE.-Add Sodium Carbonate to a solution of Calcium Hypophosphite, and evaporate the filtrate. Ca(PH2O2)2+Na2CO3 = CaCO3+2NaPH2O2.

CHARACTERS.-Small colorless, transparent, rectangular plates of a pearly lustre, or a white granular powder; odorless, and having a saline taste. It is deliquescent on exposure to moist air. Solubility.—In about 1 part of water and 25 parts of Alcohol; in o.12 part of boiling water and 1 part of boiling Alcohol.

IMPURITIES.-Calcium, sodium carbonate, caustic alkali, arsenic, heavy metals.
It is used to prepare Syrupus Hypophosphitum.
Dose, 1 gm. (15 gr.).

4. ACIDUM HYPOPHOSPHOROSUM.-Hypophosphorous Acid. Abv.Acid. Hypophos. A liquid containing not less than 30 per cent. nor more than 32 per cent. of Hypophosphorous Acid.

SOURCE. Heat Phosphorus with solution of Potassium or Sodium Hydroxide; the hypophosphite thus obtained is decomposed with Sulphuric or Tartaric Acid; filter the concentrated solution, and concentrate under the air-pump (heat decomposes it) until the desired strength is reached.