The dried leaves of Digitalis purpurea Linne (Fam. Scrophulariaceae), collected from plants of the second year’s growth, at the commencement of flowering.

Habitat.—Foxglove grows wild in the temperate parts of Europe, where it flowers in the middle of summer. In this country it is cultivated for ornamental and for medical use.

Properties.—Foxglove is without odor in the recent state, but acquires a faint narcotic odor when dried. The color of the dried leaf is a dull pale green, modified by the whitish down upon the under surface; that of the powder is a fine deep green.

Constituents.—Digitalein, Digitonin, Digitalin and Digitoxin, the latter is most poisonous and active. Said to be cumulative.

Dose.—Digitalis leaves, horses, 15 gr. to 1 dr.; cattle, 30 gr to 1¹/₂ dr.; sheep and pigs, 5 to 15 gr.; dogs, ¹/₂ to 3 gr.

Active Principles.—Digitoxin—It occurs in crystals, soluble in alcohol and chloroform, slightly in ether, and insoluble in water; said to be cumulative.

Dose.—Horses and cattle, ¹/₈ to ¹/₄ gr.; dogs, ¹/₂₅₀ to ¹/₅₀ gr.

Digitalein, an amorphous, bitter substance, soluble in water and alcohol and non-cumulative.

Dose.—Same as digitoxin.

Digitalin, a very bitter, crystalline substance, soluble in alcohol, and slightly soluble in water and ether.

Dose.—Same as for digitoxin.

Digitonin, resembling or identical with saponin of senega. White, amorphous powder, soluble in water. It is a heart depressant, muscular paralyzant and powerful irritant, besides being antagonistic to digitalis. In addition to these principles there are: Digitin, an inactive substance. Digitalic and antirrhinic acids. Tannin coloring matter, starch, sugar, gum, a volatile oil, salts, etc., common to most vegetables.

PREPARATIONS

EXTRACTUM DIGITALIS—EXTRACT OF DIGITALIS

Made by maceration and percolation with alcohol and water; distillation of alcohol and evaporation to pilular substance.

Dose.—Horses and cattle, 5 to 10 gr.; sheep and pigs, ¹/₂ to 2 gr.; dogs, ¹/₈ to 1 gr.

FLUIDEXTRACTUM DIGITALIS—FLUID EXTRACT OF DIGITALIS

Prepared by maceration and percolation with alcohol and water, and evaporating so that 1 c. c. equals 1 gm. of the crude drug.

Dose.—Horses, 10 m. to 1 dr.; cattle, 30 m. to 1¹/₂ dr.; sheep and pigs, 5 to 15 m.; dogs, ¹/₂ to 2 m.

TINCTURA DIGITALIS—TINCTURE OF DIGITALIS

Composed of powdered digitalis 100 parts with sufficient alcohol and water to make 1000 parts. By maceration and percolation.

Dose.—Horses and cattle, 2 to 4 dr.; sheep and pigs, ¹/₂ to 1 dr.; dogs, 5 to 20 m.

INFUSUM DIGITALIS—INFUSION OF DIGITALIS

Composed of digitalis 15 parts, alcohol 100 parts, cinnamon water 150 parts, boiling water 500 parts, cold water to make 1000 parts. By maceration.

Dose.—Horses and cattle, 2 to 4 oz.; sheep and pigs, ¹/₂ to 1 oz.; dogs, 1 to 4 dr.

There are several substitutes for digitalis found in commerce.

Actions.—A cardiac and vascular tonic and stimulant, a motor excitant, paralyzant, anaphrodisiac, it is an indirect diuretic and an emetic, irritates the mucous membrane.

The heart is slowed but the force is increased; digitalis stimulates the cardiac motor ganglia, the inhibitory apparatus and the vaso-motor centers, contracting the arterioles and thereby greatly raising the arterial tension; large doses exhaust and paralyze the heart.

Its diuretic action is very complex, one of the active principles, digitalin, increases the arterial pressure by contracting the blood vessels of the body, while the large renal arteries are dilated by two of its active principles, digitoxin and digitalein. On this account digitalis is an ideal diuretic.

Uses.—It is used as a cardiac stimulant in full doses, followed by small ones; used in heart and cardiac debility from any cause, irregularity of the heart due to debility; used in dropsical conditions, combined with acetate or nitrate of potash; it is useful in congestion of organs, useful in the first stages of pneumonia and scarlatina; as a diuretic over the region of the kidneys this can be used two or three times daily; when internal remedies fail to increase the action of the kidneys this is very effectual. Useful in palpitation of the heart due to overexertion. Digitalis is occasionally employed with good results as a poultice of the leaves, applied over the loins to promote diuresis, or in local inflammation, to contract blood vessels.