This definition requires modification, as there are many substances clearly in themselves not emetics, which will, under certain circumstances, act as such. Thus Castor Oil or Copaiba, from their nauseous taste, will excite violent vomiting in some persons; disgusting sights and smells have a similar effect; and almost any substance, taken in excess, will give rise to the same action. The following observations are not directed to these, but only to these medicinal substances which uniformly and in moderate doses produce vomiting. The medicines chiefly employed as emetics are Tartar Emetic, Ipecacuanha, Emetin, the Sulphates of Zinc and Copper, and Mustard. There are others of minor importance, as Squills, Tobacco, Chamomile Flowers, Ammonia, Salt, &c.

* Brit. For. Med. Rev., April 1850. Ibid.

Amer. Journ. of Med. Sciences. April 1851.

The objects for which they are employed. 1. To remove from the stomach any crude indigestible matters, or poisonous substances. 2. To depress the vascular and muscular systems.

3. To Promote The Biliary, Cutaneous, And Pulmonary Secretions

4. To Promote The Absorption Of Other Medicines, Internally Administered

5. To check internal hAemorrhage. 6. To dislodge foreign bodies inpacted in the throat or air-passages.

Contra-indications. 1. Diseases of the heart and large vessels.

2. Aneurism Of The Aorta

3. Predisposition to Apoplexy and cerebral affections in general. 4. Hernia. 5. Prolapsus of the rectum or uterus. 6. The latter months of pregnancy. 7. An irritable state of the stomach. 8. Great debility. 9. Gastritis.

Their occasional ill effects are: - 1. Abortion. 2. Hernia.

3. Apoplexy, And Comatose Affections

4. HAemoptysis. 5. Suffocation. 6. Prolapsus of the uterus or rectum. 7. Rupture of the abdominal muscles. These effects, though rare, indicate the necessity of caution in their exhibition.

Their action is promoted by drinking plentifully of warm diluents, and by tickling the fauces with a feather. Opium impedes their action.