Clinical experience has certainly demonstrated its utility as a nutrient tonic to the nervous and osseous tissues. In neurasthenia and chronic nervous exhaustion it is highly efficacious. Some cases of neuralgia, particularly of the fifth nerve and accompanied by great debility, may be relieved by full doses administered every four hours.

It is claimed by some observers that attacks of angina pectoris have been completely relieved by phosphorus.

It has proved of great value in caries, delayed resolution of bone, osteomalacia, and rachitis, and the drug is credited with the cure of pernicious anemia, though it is singular, if the drug possesses any-real value in this disease, that the fact has been recognized by so few observers. Such able men as Fox and Broadbent praise its efficacy in lymphadenoma. It possesses some value in the insomnia of the aged and the wakefulness of cerebral anemia. Phosphorus is also a valuable remedy in functional impotence.

Administration. - Since many persons have a peculiar susceptibility to phosphorus, its administration should begin with small doses, and, should it be thought necessary to prolong the administration for an indefinite period, the tendency of the drug to produce general steatosis should not be forgotten.

The phosphorus pill is undoubtedly the best form in which to administer the drug, though it possesses the disadvantages of being insoluble in the intestinal fluids and of producing more or less irritation of the gastro-intestinal mucous membrane. This latter effect is usually unnoticed under ordinary medicinal dosage on a full stomach. The liquid preparations of phosphorus are more unstable, rapidly tending to become inert by oxidation.

Official Derivatives

Calcii Hypophosphis - Calcii Hypophosphitis - Calcium Hypophosphite (U. S. P.). - Origin. - Obtained by heating phosphorus with milk of lime and exposing the mixture to the air.

Description and Properties. - Colorless, transparent, monoclinic prisms, or small, lustrous scales, or a white, crystalline powder; odorless, having a nauseous, bitter taste, and permanent in the air. Soluble in 6.5 parts of water and in 6 parts of boiling water; insoluble in alcohol. It should contain not less than 98 per cent. of pure calcium hypophosphite.

Dose, 5-6 grains (0.3-0.4 Gm.) [7 1/2 grains (0.5 Gm.), U. S. P.].

Calcii Ph6sphas Praecipitatus - Calcii Phosphatis Praecipitati - Precipitated Calcium Phosphate (U. S. P.). - Origin. - Prepared by the action of hydrochloric acid and water upon bone-ash, the addition of solution of ammonia to render the mixture of an alkaline reaction, and washing and drying the precipitate. It should contain not less than 99 per cent. of pure calcium phosphate.

Description and Properties. - A light, white, amorphous powder, odorless and tasteless, permanent in the air. Almost insoluble in cold water; partly decomposed by boiling water, which dissolves out an acid salt; almost insoluble in acetic acid, except when freshly precipitated; easily soluble in hydrochloric or nitric acid; insoluble in alcohol.

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

Sodii Hypophosphis - Sodii Hypophosphitis - Sodium Hypophosphite (U. S. P.). - Origin. - Prepared by adding sodium carbonate to a solution of calcium hypophosphite and evaporating the filtrate. It should contain not less than 98 per cent. of pure sodium hypophosphite.

Description and Properties. - Small, colorless, transparent, rectangular plates of a pearly lustre, or a white, granular powder, odorless, and having a bitterish-sweet, saline taste. Very deliquescent on exposure to moist air. Soluble in 1 part of water and in 30 parts of alcohol, also in 0.12 part of boiling water and in 1 part of boiling alcohol; slightly soluble in absolute alcohol; insoluble in ether. Sodium hypophosphite should be kept in well-stoppered bottles.

Dose, 5-10 grains (0.3-0.6 Gm.) [15 grains (1 Gm.), U. S. P.].

Potassii Hypophosphis - Potassii Hypophosphitis - Potassium Hypophosphite (U. S. P.). - Origin. - Prepared in a similar manner to calcium hypophosphite, or by double decomposition of calcium hypophosphite and potassium carbonate. It should contain not less than 90 per cent. of pure potassium hypophosphite.

Description and Properties. - White, opaque, hexagonal plates, or crystalline masses, or a granular powder, odorless, and having a pungent, saline taste; very deliquescent. Soluble in 0.6 part of water and in 7.3 parts of alcohol. Potassium hypophosphite should be kept in well-stoppered bottles.

Dose, 5-30 grains (0.3-2.0 Gm.) [7 1/2 grains (0.5 Gm.1, U. S. P.].

Acidum Hypophosphorosum - Acidi Hypophosphorosi - Hypophosphorous Acid (U. S. P.). - Definition. - A liquid, HPH1O2, composed of 30 per cent. by weight of absolute hypophosphorous acid and 30 per cent. of water.

Description. - A colorless, odorless liquid having an acid taste. Miscible in all proportions with water. It is a powerful reducing agent, precipitating metallic silver from solutions of silver nitrate, calomel from corrosive sublimate, etc.; when heated with copper sulphate a yellow precipitate of copper hydride is formed (difference from phosphorous acid). It is used in the preparation of acidum hypophosphorosum dilutum.

Incompatibles. - Incompatible with arsenical salts, and in general with substances that are more or less easily reduced.

Acidum Hypophosphorosum Dilutum - Acidi Hypophosphorosi Diluti -Diluted Hypophosphorous Acid (U. S. P.). - Definition. - A liquid composed of 10 per cent. by weight of absolute hypophosphorous acid and 90 percent, of water.

Description and Properties. - A colorless liquid, without odor, and having an acid taste. Specific gravity about 1.042. Miscible in all proportions with water.

Dose. - It is rarely used as a therapeutic agent by itself, but in the syrup of the hypophosphites [8 minims (5 Cc), U. S. P.].

Syrupus Hypophosphitum - Syrupi Hypophosphitum - Syrup of Hypo-phosphites. - Formula. - Calcium hypophosphite, 45; sodium hypophosphite, 15; potassium hypophosphite, 15; diluted hypophosphorous acid, 2; tincture of fresh lemon peel, 5; sugar, 650; sufficient water to make 1000.

Dose. - 1-2 fluidrams (4.0-8.0 Cc.) [2 fluidrams (8 Cc), U. S. P.].

Syrupus Hypophosphitum Compositus - Syrupi Hypophosphitum Com-pttsitiCompound Syrup of Hypophosphites (U. S. P.). - Syrupus hypophosphitum cum Ferro (U. S. P., 1890) is dropped, but this may take its place, as it contains iron, as ferric hypophosphite 0. 25 per cent. It contains 5, calcium, potassium, sodium, iron and manganese, hypophosphites, hypophosphorous acid, quinine, and strychnine. It is adopted from the National Formulary and is similar to a number of well-known proprietary preparations.

Dose. - Average dose: 2 fluidrams (8 Cc), U. S. P.

Elixir Ferri, Quininae et Strychninae Phosphatum - Elixiris Ferri, Quininae et Strychninae Phosphati - Elixir of Iron, Quinine and Strychnine Phosphates. (U. S. P.). - Each fluidram contains 1 grain (0.0647 Gm.) of ferric phosphate, 1/2 grain (0.0324 Gm.) of quinine, and 1/64 grain (0.001 Gm.) of strychnine. This is the official representative of a large class of popular preparations on the market.

Dose. - Average dose: I fluidram (4 Cc), U. S. P.

Glyceritum Ferri, Quininae et Strychninae Phosphatum - Glyceriti Ferri, Ammonias et Strychninae Phosphati - Glycerite of the Phosphates of Iron, Quinine, and Strychnine (U. S. P.). - This preparation is a concentrated form of one of the popular and useful combinations of tonics which might well replace some of the many proprietary preparations; it is prepared according to a fixed and definite formula (see U. S. P.), whereas the latter class are made according to the special formulae of the different manufacturers. (See also Elixir Ferri, Quininae et Strychninae Phosphatum). This glycerite is a stable solution which may be kept in stock, and from which the syrup of the phosphates of iron, quinine, and strychnine may readily be prepared.

Dose. - Average dose: 15 minims (1 Cc), U. S. P. 1 Cc. contains \\ grains (0.080 Gm. =80 milligrammes) of soluble ferric phosphate, 1 3/5 grains (0.104 Gm. = 104 milligrammes) of quinine, and 1/80 grain (0.0008 Gm. =0.8 milligrammes) of strychnine. The ratio of quinine to strychnine is four times as great in the glycerite as in the elixir.

Antagonists and Incompatibles. - The sodium and potassium hypophosphites are incompatible with the soluble salts of mercury and silver, and the soluble phosphates and carbonates are incompatible with calcium hypophosphite.

Synergists. - Phosphorus, cod-liver oil, and the restoratives generally.

Physiological Action. - Although not possessing the active and poisonous properties of phosphorus, the hypophosphites are useful as tonic stimulants, being particularly valuable in general furunculosis.

The calcium phosphate adds the action of calcium to that of the hypophosphite.

The zinc phosphide is more active. In this preparation the zinc ion plays an important part.

Therapeutics. - Externally and Locally. - The calcium phosphate, combined with a little free phosphoric acid, has been recommended by Doubenski in the treatment of tuberculous ulcerations. "Cold abscesses and fistulous tracts were treated by packing with gauze soaked with a solution of 5 parts to 100."

Internally. - The hypophosphites are useful as general tonics. Phosphoric acid has little action as determined by animal experimentation, but negative evidence from such research has no bearing, in view of much positive evidence derived from clinical use. In chlorosis, anemia, scrofula, and tuberculosis they have been highly recommended. In the opinion of many the benefit derived from their use in the cachexiae mentioned is slight compared with that of cod-liver oil and the hygienic influences rendered serviceable in these conditions.

Administration. - The zinc phosphide is best given in pill form. The hypophosphites and calcium phosphate may be given in capsules, though the syrup of the hypophosphites is usually preferred. In patients who cannot take sugar, even in small quantities, the syrup may be contraindicated.