The American plant is asserted to possess qualities similar to those of Digitalis, and to incite uterine contractions. It has been used in cardiac affections, dropsies, uterine hemorrhages and amenorrhoea, also as an abortifacient.

VITELLUS, Yolk of Egg, is the yolk of the egg of the domestic fowl, Gallus Bankiva, var. domesticus. It is a viscid, reddish-yellow, opaque liquid, of bland taste, alkaline reaction, odorless, and may be regarded as a dense emulsion of oil suspended in water by means of albumen. It is coagulated by heat or by alcohol and contains Vitellin, which is a proteid related to casein, Cholesterin and Albumin, besides fat, inorganic salts, sugar, etc.

Preparation.

GLYCERITUM VITELLI, Glycerite of Yolk of Egg, Glyconin,-consists of Vitellus 45, Glycerin 55 parts rubbed together until thoroughly mixed.

Physiological Action and Therapeutics.

YOLK OF EGG is highly nutritive and forms a useful article of diet in exhausted conditions of the system, but its chief use in medicine is for emulsionizing oils and camphors. The GLYCERITE has the consistence of honey and forms an opaque emulsion with water. It is a very good vehicle for cod-liver oil (see ante, page 265), and an excellent protective application for burns, erysipelas, fissure of the nipples and many cutaneous disorders. It is also used as a cosmetic, and may be employed as an aliment.

XANTHOXYLUM, Prickly Ash,-is the bark of Xanthoxylum fraxineum, the northern species, and of Xanthoxylum carolinianum, the southern species of an indigenous shrub of the nat. ord. Rutaceæ, having small, greenish flowers, alternate unequally pinnate leaves, leaflets punctate with pellucid dots, stems and leafstalks armed with prickles. The bark of both species comes in curved or quilled fragments, of a brownish-gray color externally with whitish patches, and minute black dots, faintly furrowed, inodorous, bitter and pungent. That of X. fraxineum is about inch thick, has several two-edged spines each 14inch long, the bark of X. carolinianum is twice as thick as the other and is marked by many conical, corky projections, and by stout brown spines, arising from corky bases. It contains a volatile oil, a fixed oil, resin, gum, coloring matter and an alkaloid,

Xanthoxyline, which is identical with Berberine (see ante, page 100.) Dose, of the powdered bark, gr. x-xxx.

Preparations.

EXTRACTUM XANTHOXYLI FLUIDUM,-Dose, 3ss-j.

DECOCTUM XANTHOXYLI (Unofficial),-3j to the quart. Dose, a pint during 24 hours in divided doses.

Physiological Action.

Xanthoxylum is a stimulant and aromatic bitter, a local and systemic sialogogue, diaphoretic, diuretic and emmenagogue. Its taste is aromatic, soon becoming acrid and bitter and causing profuse salivation, tingling in the tongue and increased secretion from stomach, intestines, liver and pancreas. It also increases the cardiac action and raises the arterial tension, and is classed among the vegetable alteratives, with Mezereum, Guaiac, Stillingia, etc.

Therapeutics.

Xanthoxylum has a high reputation in chronic rheumatism, myalgia, lumbago and similar disorders, also in jaundice from catarrh of the bile ducts, in dropsies, chronic pharyngitis and constitutional syphilis. In old cases of pharyngitis, the mucous membrane being glazed and dry, the decoction should be used as a gargle and mx-xxx of the fluid extract taken internally thrice daily. The bark, used as a masticatory, is a popular remedy for toothache, and has been frequently successful in paralysis of the tongue.

ZEA MAYS, Maize, Indian Corn.-This well-known species of the nat. ord. Graminaceæ, though itself unofficial, is the source of two drugs one of which is official, viz.—

Ustilago, Corn Smut,-Ustilago Maydis, nat. ord. Fungi, grown upon the stems, the pistils and the male inflorescence (tassel) of Zea Mays. It occurs in irregular, globular masses, sometimes 6 inches thick, and consisting of a blackish membrane, inclosing numerous globular, minute spores, their surfaces covered with echinulate warts. Its odor and taste are unpleasant, and it contains fixed oil, resin, pectin, gluten, sugar, an acid resembling the Sclerotic Acid of Ergot, and a volatile principle called Secaline, which is supposed to be identical with Trimethylamine.

Preparation.

EXTRACTUM USTILAGINIS FLUIDUM (Unofficial),—may be made according to the general rule. Dose, mxv-3j.

Stigmata Maydis, Stigmata of Maize, Corn Silk (Unofficial), should be gathered when the tassel has well shed its pollen. Its active principle is said to be Maizenic Acid.

Preparation.

EXTRACTUM STIGMATARUM MAYDIS FLUIDUM (Unofficial),-made by the general rule for fluid extracts. Dose, 3j-ij.

Physiological Action and Therapeutics.

The properties of USTILAGO, so far as examined, resemble those of Ergot and Nux-vomica combined. It is a spinal excitant, exalts sensibility and reflex action, producing tonic convulsions on the least irritation of the skin. It slows the heart by stimulation of the pneumogastric, dilates the pupil, causes muscular paresis, and death by tetanus of the respiratory muscles or by exhaustion. Experiments on its reputed oxytocic action have not substantiated the claims made for it in this respect, though it is said to have produced abortion in cows and other animals, after they had eaten the diseased grain. As a therapeutic agent Ustilago has been very little used, and when employed it has been as a substitute for Ergot.

STIGMATA MAYDIS is a certain but mild diuretic when given in full doses at short intervals. It is by some observers considered demulcent and anodyne, and is generally believed to have a specific or alterative influence over many disorders of the genitourinary passages and the urinary bladder. It has been used with considerable success in incontinence of urine, uric and phosphatic gravel, gout, rheumatism, urethritis, pyelitis, acute and chronic cystitis, cardiac dropsy and obstructive valvular disease of the heart.

ZINCUM, Zinc, Zn,—is metallic Zinc, in the form of thin sheets, or irregular, granulated pieces, and is a bluish-white metal, having the sp. gr. 6.9. It occurs native as a Sulphide (Blende), as a Carbonate and a Silicate (Calamine), as a Red Oxide (Zincite), and as a mixture of Zinc Oxide with Oxide of Iron and Manganese (Franklinite). Zinc is soluble in the weakest acids, and therefore should never be used for culinary vessels. Its salts are all more or less active poisons. Metallic Zinc is not employed as a medicine.

Zinc Compounds and their Preparations.

ZINCI ACETAS, Acetate of Zinc, Zn(CH„O)„.3H2O,-soft, white, micaceous or pearly, six-sided tablets or scales, somewhat efflorescent in dry air,

of faintly acetous odor, sharp metallic taste and a slightly acid reaction; soluble in 3 of water and in 30 of alcohol at 59° F., in 11⁄2 of boiling water and in 3 of boiling alcohol. Used locally as an astringent in solution of gr. jor ij to 3j, or internally in doses of gr. 2-ij.

ZINCI CARBONAS PRÆCIPITATUS, Precipitated Carbonate of Zinc, (ZnCO,),.3Zn(HO), -a white, impalpable powder, permanent in the air, odorless and tasteless, insoluble in water or alcohol, but soluble in acids with copious effervescence. When strongly heated it loses water and carbonic acid gas, leaving a residue of oxide of zinc. Used locally as a protective.

ZINCI CHLORIDUM, Chloride of Zinc, ZnCl,,-a white, crystalline powder, deliquescent, odorless, of caustic, saline, and metallic taste and acid reaction, very soluble in water and in alcohol, forming a clear or only faintly opalescent solution. Tonic and escharotic. For internal use a solution in Spirit of Ether is the most convenient form, of the strength of 3ss-3iij, of which from 4 to 8 drops may be given twice daily. Strength of injections and collyria, gr. j-ij ad 3j.

LIQUOR ZINCI CHLORIDI,-an aqueous solution of Zinc Chloride containing about 50 per cent. of the salt. A clear, colorless, odorless liquid, of a very astringent, sweetish taste and an acid reaction. A powerful disinfectant for sinks, drains, etc. Used also as an injection in gonorrhoea, leucorrhoea, etc., in dilute solution, 1⁄2 to 1 per cent. Burnett's Disinfecting Fluid is similar to the above but slightly stronger.

ZINCI IODIDUM, Iodide of Zinc, ZnI,,-a white, granular powder, very deliquescent, odorless, of sharp, saline and metallic taste and acid reaction, very soluble in water and in alcohol. Dose, gr. ss-ij in syrup.

ZINCI OXIDUM, Oxide of Zinc, ZnO,-a soft, pale-yellowish powder, permanent in the air, odorless and tasteless, insoluble in water or alcohol, but soluble in acids without effervescence. Dose, gr. j-x, in pill.

UNGUENTUM ZINCI OXIDI,-strength 20 per cent., made with Benzoinated Lard, thoroughly mixed.

ZINCI SULPHAS, Sulphate of Zinc, ZnSO,.7H,O,-small colorless prisms or acicular needles, slowly efflorescing in dry air, odorless, of sharp, saline, nauseous and metallic taste and acid reaction, soluble in 0.6 of water, insoluble in alcohol. Dose, as emetic, gr. x-xxx,-as a tonic and astringent, gr. †'f-ij, in pill. For Villate's Solution, see ante, page 169.

ZINCI VALERIANAS, Valerianate of Zinc, Zn(C,H,O,),.H,O,-soft, white, pearly scales, of sweet and styptic taste and acid reaction; soluble in 100 of water and in 40 of alcohol at 59° F. Dose, gr. -ij, in pill.

[The BROMIDE OF ZINC is described under BROMUM, see page 103, and the PHOSPHIDE under PHOSPHORUS, on page 289.]

Physiological Action and Therapeutics.

Zinc Salts are astringents, but milder ones than the salts of Lead. Its soluble compounds (the Chloride, Iodide, Sulphate and Acetate) are corrosive poisons, causing violent gastroenteritis, and in some cases profound nervous depression. The CHLORIDE is a very powerful and painful escharotic or rather mummifier of the tissues, having great affinity for water, coagulating albumen and shrivelling the vessels. It is a very active disinfectant. The SULPHATE is also escharotic and a specific

emetic, acting promptly by direct irritation of the stomach, and without much depression or after-nausea. In small doses it is tonic and astringent, in larger it would be a severe irritant but for its causing prompt emesis. The ACETATE resembles the sulphate in action. The OXIDE used externally is a mild, soothing astringent; used internally it enters the blood as a lactate or chloride, and acts as a mild astringent and as a nervous sedative. Being almost insoluble in the stomach, it has but feeble diffusive power and consequently but slight activity. The CARBONATE reseinbles the Oxide in action. The IODIDE locally is a powerful escharotic and has been supposed to possess some alterative powers when given internally in addition to its astringent qualities as a zinc salt. The VALERIANATE acts as a nervous sedative, but its properties are in all probability due to its base and not to the acid combined with it.

Continued use of zinc salts produces symptoms similar to those of chronic lead-poisoning, but of much less gravity. They manifest much less tendency to accumulate in the system than other metallic salts, and are excreted much more rapidly. Elimination takes place chiefly by the liver and intestinal glands.

[The actions of the Bromide and Phosphide are described respectively on pages 105 and 290.]

Antidotes and Incompatibles.

Lime-water, mucilaginous drinks, soap, tannic acid, milk, Potassium and Sodium Carbonates if given early, are the antidotes in poisoning by the salts of zinc. Incompatibles are—lime-water, alkalies and their carbonates, nitrate of silver, and vegetable astringents. Acetate of Lead produces double decomposition with zinc salts, but it is often used in solution with the sulphate as an injection.

Therapeutics.

Zinc salts are chiefly employed in weak solution as mild astringent applications in catarrhs of mucous membranes, such as conjunctivitis, gonorrhoea, etc., and as unguents and lotions in skindiseases, particularly eczema, impetigo, herpes and erythema. The CHLORIDE is made into a paste with flour and glycerin for the destruction of lupus, epithelioma and other morbid growths, and for opening abscesses in locations where puncture or incision might be dangerous. The cuticle, if unbroken, should be removed by strong water of ammonia before the paste is applied, as it will not act through the epidermic tissue. It is a commonly used disinfectant and deodorant, and in weak solution (miij-v of the Liquor to 3j of water) makes a good lotion for putrid ulcers, and still weaker (gr. j-ij to the pint), is an excellent injection