Agi = 107.8.

The element silver (AS. seolfer; L. argentum: Gr,

white

- i. e., its bright, shining color), official 1830-1880, occurs natively as metal and sulphide; the latter, being along with lead sulphide - argentiferous galena - is simply roasted, when lead oxidizes into litharge and pure silver separates. Silver may also be obtained by amalgamation - dissolving it in mercury and distilling the amalgam, when mercury, being volatile, passes over, and silver remains. It is the whitest metal, best conductor of heat and electricity, takes brilliant polish, malleable, ductile, sp. gr. 10.4-10.5.

Tests for Silver Salts: 1. H2S or NH4SH precipitates black silver sulphide, Ag2S. 2. Hydrochloric acid, or any soluble chloride, precipitates white curdy silver chloride, AgCl, insoluble in hot HNO3, but soluble in ammonia water. 3. Alkaline hydroxides precipitate brown silver oxide, Ag2O, soluble in ammonia water. 4. Metallic copper, zinc, or iron precipitates metallic silver.

Argenti Nitras. Silver Nitrate, AgNO3. - (Syn., Arg. Nit., Lunar Caustic; Fr. Azotas (Nitras) Argenticus, Azotate (Nitrate) d'Argent, Nitre lunaire; Ger. Argentum nitricum (Crystallizatum), Silbernitrat, Salpetersaures Silberoxyd, Silbersalpeter.)

Manufacture: Dissolve silver in nitric acid by heat, evaporate to dryness to expel free acid, dissolve dry mass in hot water, crystallize - 3Ag + 4HNO3 = 3AgNO3 + NO + 2H2O. It is in colorless, transparent, tabular, rhombic crystals, gray or grayish-black on exposure to light in presence of organic matter, odorless, bitter, caustic, strongly metallic taste, soluble in water (.4), boiling water (.1), alcohol

(30), boiling alcohol (6.5), melts at 200° C. (302° F.) into yellowish liquid which on cooling congeals into pure white crystalline mass; aqueous solution clear, colorless, neutral; contains 99.8 p. c. of pure salt. Tests: 1. Aqueous solution + hydrochloric acid - white curdy precipitate, insoluble in nitric acid, readily soluble in ammonia water. 2. Aqueous solution (1 in 10) + a drop of diphenylamine T. S. onto which pour carefully sulphuric acid to form separate layer - deep blue at line of contact. Impurities: Copper, etc. Should be kept dark, in dark amber-colored vials. Dose, gr. 1/8 - 1/2 (.008-.03 Gm.), ter die, in pill with bitter extracts, but not with bread containing salt, as this hastens decomposition; best given on empty stomach.

Preparation. - 1. Argenii Nitras Fusus. Molded Silver Nitrate. (Syn., Arg. Nit. Fus., Fused Silver Nitrate, Lunar Caustic, Lapis Infernalis; Br. Argenti Nitras Induratus, Toughened Caustic; Fr. Azotas (Nitras) Argenticus Fusus, Azotate (Nitrate) d'Argent fondu, Pierre infernale; Ger. Argentum nitricum (fusum), Geharteter Hollen-stein, Geschmolzenes Saltpetersaures Silberoxyd.)

Manufacture: Add hydrochloric acid 4 Gm. to silver nitrate 100 Gm., melt, stir, mold. It is a white hard solid, generally in pencils or cones, fibrous fracture, gray, grayish-black on exposure to light, odorless, bitter, caustic, strongly metallic taste; contains 94.5 p. c. of pure salt. Tests and Impurities: Same as for argenti nitras. The hydrochloric acid forms some silver chloride that toughens the compound, permitting more ready handling without breaking. Should be kept dark, in dark amber-colored vials.

Properties and Uses. - Alterative, stimulant, astringent (only externally), haemostatic, escharotic (but does not act deeply), sedative, epilepsy, chronic spinal inflammation, locomotor ataxia, spasmodic tabes, ulcerations of alimentary tract, subacute gastritis, pyrosis, ulcer of stomach, chronic diarrhoea, catarrh of the gall-ducts, typhoid fever, neuralgia, dysentery, cholera, vomiting of pregnancy, chronic jaundice, abnormal heart-action, bronchitis. Externally - diphtheritic exudations, croup (10 p. a), chronic ulceration, simple inflammation, chronic laryngitis (1-5 p. c), aphonia, whooping-cough, sore throat of speakers, tubercular and syphilitic tonsillitis, enlarged lymphatic glands, abscesses, iritis, sciatica, conjunctivitis (1/2-l p. c), corneal ulcers, hemorrhages from leech-bites, bed-sores, poisoned and other wounds, mercurial sore mouth, chancre, smallpox, herpes, intertrigo, burns, erysipelas, gonorrhoea, leucorrhoea, otorrhoea, neck of bladder inflammation, vesical catarrh, urethral strictures, involuntary seminal emissions, enlarged prostate, corns, rectal ascarides.

Also much used in making indelible ink, dyes for hair, beard, etc. When used on the hair for a long time the system usually absorbs sufficient to produce poisonous symptoms, with permanent constitutional weakness. The stains may be removed by applying a solution of potassium cyanide, or potassium iodide, or tincture iodine + ammonia.

Poisoning: Have intense abdominal pain, muscular spasms, vomiting, purging, face livid, skin moist, black vomit containing coagulated mucus, coma, convulsions, paralysis, respiratory disturbance; when chronic have skin, conjunctivae, and labial mucous membrane of a permanent slaty color, gastric ulceration. Administer weak draught of sodium chloride (to decompose the nitrate), egg-white, milk, tannin, followed by emetic, opium for pain, sodium hyposulphite baths, stimu--lants - alcohol, strychnine, atropine, etc.; chronic silver-poisoning, argyria, which gives slate-blue color to skin, livid cadaveric appearance, is usually not curable but palliated by potassium iodide.

Incompatibles: Alkalies, carbonates, chlorides, hydrochloric acid, tannin, potassium iodide, arsenic solution.

Synergists: Copper, lead, zinc.

Argenti Oxidum. Silver Oxide, Ag2O. - (Syn., Arg. Oxid., Oxidum Argenticum, Argentum Oxydatum, Argentic Oxide; Fr. Oxyde d'Argent; Ger. Silberoxyd.)

Manufacture: Shake silver nitrate solution with liquor potassii hydroxidi, wash precipitate - 2AgNO3 + 2KOH = Ag2O + 2KNO3, + H2O. It is a heavy, brownish-black powder, easily reduced by exposure to light, odorless, metallic taste, slightly soluble in water with alkalinity, insoluble in alcohol, soluble in. nitric acid; decomposes at 300° C. (572° F.), liberating oxygen, with residue of metallic silver; contains 99.6 p. c. of pure salt. Impurities: Copper, chloride. Should be kept in well-stoppered, dark amber-colored vials, and must not be triturated with readily oxidizable or combustible substances, nor brought in contact with ammonia. Dose, gr. 1/4-2 (.016-. 13 Gm.), ter die, in pill: externally, ointment (10-20 p. c).

Properties and Uses. - Similar to nitrate, but much weaker. Slight caustic, sedative; nausea, cardialgia, pyrosis, pains in the stomach, dysentery, diarrhoea, night-sweats, dysmenorrhoea, menor-rhagia, leucorrhoea, dilated uterus with flooding, taenia, venereal sores, gonorrhoea, hemorrhages, gastric ulcers, dyspepsia, catarrhal affections, colors skin somewhat.

Incompatibles: Chlorides, organic substances, creosote, etc.; these are oxidized, forming explosive compounds.

Allied Salts:

1. Argenti Cyanidum. Silver Cyanide, AgCN, official 1840-1910. - Obtained by distilling potassium ferrocyanide, sulphuric acid, and water together, passing the evolved gas, HCN, into an aqueous solution of silver nitrate, washing, drying the precipitate - AgNO3 + HCN = AgCN + HNO3; or add solution of silver nitrate to a solution of potassium cyanide until precipitation ceases, filter, wash well - AgNO3 + KCN = AgCN + KNO3. It is a white powder, odorless, tasteless, permanent in dry air, brownish on exposure to light, insoluble in water, alcohol, cold nitric acid, soluble in boiling nitric acid, ammonia water, sodium thiosulphate T. S., potassium cyanide T. S., fused gives off cyanogen gas, leaving residue of metallic silver (80.48 p. c.); contains 99.9 p. c. of pure salt, corresponding to 80.48 p. c. of metallic silver. Should be kept dark, in dark amber-colored bottles. Rarely used in medicine, but in preparing diluted hydrocyanic acid. Dose, gr. 1/60 - 1/20 (.001-.003 Gm.).

2. Argenti Iodidum. Silver Iodide, Agl, official 1880-1900. - Obtained by double decomposition between silver nitrate and potassium iodide, washing and drying the precipitate - AgNO3 + KI = Agl + KNO3. It is a heavy, amorphous, yellow powder, unaltered by light; if impure becomes greenish-yellow, odorless, tasteless, insoluble in water, alcohol, diluted acids, soluble in solution of potassium cyanide. Impurities: Chloride, bromide. Should be kept in the dark, in amber-colored vials. Dose, gr. 1/4 - 2 (.016-. 13 Gm.), ter die, in pill. Similar to nitrate, and from its not coloring the skin, once was believed a better salt, but not now so considered; used in syphilis, visceral neuralgia, asthma, chorea, whooping-cough.

3. Argenti Nitras Mitigatus. Mitigated Silver Nitrate, Diluted Silver Nitrate, official 1880-1910. - Obtained by melting together at low temperature in porcelain crucible silver nitrate 30 Gm. and potassium nitrate 60 Gm., stirring until it flows smoothly, pouring into molds. Should be kept dark, in dark amber-colored bottles. Used when mild action desired.

4. Silver Vitellin. Argyrol. - This is obtained by extracting and purifying one of the wheat proteids, gliadin (similar to vitellin), and heating it 3 hours under pressure in an autoclave with diluted hydrochloric acid; to a concentrated solution of this salt add strong solution silver nitrate, dry precipitate in vacuo; contains 30 p. c. of metallic silver; occurs in black hygroscopic scales, soluble in water without deteriorating, coagulating albumin, or precipitating chlorides. Used locally in acute inflammations in 5-10-20-50 p. c. solutions - gonorrhoea (5 p. a), chronic urethritis (5-10 p. c), cystitis (10 p. a), purulent conjunctivitis (25-50 p. c), rhinitis, pharyngitis, laryngitis, vaginitis, dysentery; internally, gastric ulcer, gastritis, gastro-enteritis. Dose, gr. 5-10 (.3-.6 Gm.).

5. Protargol. Protargolum. Protein Silver Salt. - Obtained by the interaction of a silver salt and protein, rendering product soluble with solution of albumoses. Occurs as impalpable yellow powder, soluble in water (2 parts) from which silver is not precipitated by ordinary reagents - alkalies, sulphides, bromides, chlorides, iodides, heat, etc. Bactericide, antiseptic, non-irritating substitute for silver salts in gonorrhoea, conjunctivitis, cystitis, urethritis, mucous membranes of eye, ear, nose, throat. Dose, only externally: gonorrhoea (acute) injections .25-1 p. c, (chronic) 5-10 p. c; irrigations 1 in 1000 or 2000; also as bougies and tampons (5-10 p. c).