Cupri Sulphas, Copper Sulphate,—gr. vj, in water, every 15 minutes until emesis occurs; gr. xij maybe given at one time in narcotic poisoning.

Zinci Sulphas, Zinc Sulphate,—gr. vj or viij, in water, every 15 minutes until emesis. Is less irritant than the copper salt.

Hydrargyri Subsulphas Flavus, Yellow Mercuric Subsulphate, Turpeth Mineral,—gr. iij-v, in powder, with Sugar of Milk. The best emetic in croup, being tasteless. (See page 78 et seq.)

Alumen, Alum,—a teaspoonful in honey, every half hour. Is safe and efficient, but slow. (See page 97.)

Sinapis Alba, vel Nigra, White or Black Mustard,—as emetic, or more, in water. Is stimulant to the heart and circulation, also a condiment and carminative in small doses. Described under Topical Agents.

Apomorphina, Apomorphine,—an alkaloid derivative from Morphine by the action of strong acids or zinc chloride. Emetic dose by stomach. gr. ⅛-⅙, hypodermically, gr. 1/16, in a fresh solution. Is very depressant to the heart, and has caused death by cardiac failure. Is the best emetic when swallowing is difficult, but is useless in narcotic poisoning after narcosis has blunted the vagus centre. Has convulsant action on animals, and some expectorant power. (See ante, page 147.)

Apomorphinae Hydrochloras. Dose, gr. 1/20-1/10 hypodermically.

Antimonii et Potassii Tartras, Antimony and Potassium Tartrate, (Tartar Emetic),—Dose, as emetic, gr. j-ij; but it is too slow and depressant for general use. (See page 71.)

Physiological Action. The first five are local emetics, the last two are general or systemic emetics. (See ante, page 34.) The Local Emetics act chiefly by irritating the end-organs of the nerves in the pharynx, oesophagus or stomach; the General or Systemic Emetics by direct irritation of the vomiting centre in the medulla, acting through the medium of the circulation wherever introduced. Some agents act both ways, e. g., Tartar Emetic; also Zinc and Copper Sulphates, but in the cases of the two latter, their action on the stomach preponderates so much over their general action, that they are classed with the local emetics.

The action of local emetics does not continue long,—does not extend beyond the act of producing emesis, ceasing after the emetic has been evacuated,—and is not accompanied by much general depression.

Therapeutics. Emetics are employed for several purposes, among which may be mentioned the following:—

(1). To cause the expulsion of foreign bodies from any part of the oesophageal tract, or from the air-passages.
(2). To remove or evacuate the contents of the stomach.
(3). To remove an obstruction from the gall-duct.

Contraindications for their use, are—aneurism, atheroma, hemorrhagic diathesis, hernia, prolapsus uteri, and tendency to abortion (when subject is pregnant).

They are especially indicated in—

Narcotic Poisoning,—the Copper Sulphate or the Zinc Sulphate, the latter being usually preferred.
Croup and Diphtheria,—to dislodge false membrane.
Indigestion,—to relieve the overloaded stomach.

A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.