Emetics have been used in the collapse of miasmatic pernicious fever, and seem to have sometimes done good by rousing the system into reaction.

It is possible that, in the same way, they may have been beneficial in the collapse of cholera, in which an emetic of salt has been very highly commended by some practitioners.

10. Local irritation. The direct excitant effect of emetics on the gastric mucous membrane is sometimes beneficial in disease. in the torpid state of the stomach so common in dyspepsia, they were recommended by the late Prof. Chapman at the commencement of the treatment. By a local substituted action, they may also prove useful in existing irritations or other disorders of the stomach itself, on the same principle that irritants, externally applied, operate often so beneficially in eruptions upon the surface. But it would be difficult to distinguish those conditions of the stomach to which they might be applicable, from those in which their administration might be injurious; and, if used at all, with this indication, in such cases, it should be with great caution, and never when the membrane may be in any degree acutely inflamed. it is possible that they may sometimes prove useful, on this principle, in cholera, in which, as already stated, they have been recommended. it is, too, not impossible that they may have been efficacious, as has been asserted, in arresting haematemesis, by the same mode of action. Certainly, we often meet with cases of gastric disorder, with a furred tongue, uneasiness of stomach, defective appetite, constipation, etc., in which an emetic affords prompt and entire relief. in the older pathology, these were looked on as saburral cases, in which the gastric mucous membrane was supposed to throw out unwholesome secretions, as the tongue forms fur; or noxious matters were in some other way generated, which, accumulating in the stomach, proved a source of various gastric disturbance. But these conditions are now regarded as having their real seat in the tissues; and emetics if useful, must be so by changing the condition of the tissues, and not merely by evacuating the sordes.

11. Cathartic Effect. Lastly, most emetics, given in doses just insufficient to vomit, are disposed to act upon the bowels; and not unfrequently they produce the two effects conjointly. Some practitioners, availing themselves of this property of emetics, conjoin them in small doses with cathartics, to hasten, facilitate, or increase their action.

In the foregoing remarks, I have endeavoured to point out the principles upon which emetics may act beneficially, and to put the young practitioner in the position of being able to decide, for himself, in what special diseases, and in what particular conditions of each disease, he may judiciously have recourse to the medicines of this class. He will not unfrequently find several of the indications presented in the same case. Thus, in a case of bilious remittent fever, there may be occasion for the evacuation of the stomach, the excitation of the liver, and the supersedent shock upon the system; while the sedative, depletory, revulsive, and relaxing influence, and the increase of the secretions generally may be of incidental benefit. in croup, or spasmodic inflammation of the larynx, there is an indication not only for the relaxation produced by emetics, but also for their depletory and revulsive influence, and especially for their effect in increasing the mucous secretion of the air passages. in the commencing stage of inflammations generally, the sedative, the depletory, and the revulsive effects may combine to diminish if not set aside the affection. But it would be impossible, with the limitation fixed for this work, to go through the whole list of diseases, and point out the several conditions in each, which may recommend or forbid the use of these medicines. This must be left to the judgment of the practitioner, duly furnished with the principles which should serve him as guides.

Contraindications

it does not follow that an emetic must always be administered, when any condition exists which may be benefited by it. Emetics are very disagreeable medicines, and should, therefore, be avoided when they can well be dispensed with; in other words, when the same ends are likely to be accomplished in a little time by nature, or when they can be equally well attained by other less disagreeable means.

Positive contraindications are presented by active congestion of the brain threatening apoplexy, acute gastric inflammation, and the most advanced stage of pregnancy. it must be some very strong indication indeed, such for example as exists in a case of poisoning, that would justify the use of them in these conditions. The existence of hernia has been mentioned as a contraindication; but this is going too far. Hernia should always induce special caution in securing, by pressure, the hernial orifice, during the emetic act; but it should not be considered as forbidding the use of an emetic.

3. Administration

Emetics should generally be given dissolved or suspended in water. Being irritant, they should be made to come in contact equably with the whole or large portions of the mucous coat of the stomach, and not, as when given in pill or solid mass, to concentrate their action upon a small part, with the effect, perhaps, of producing an unnecessary amount of irritation.

Another good practical rule, of general though not universal application, is to administer them, not at once in the full dose which experience may have determined as in all probability sufficient to vomit, but in smaller doses, to be repeated every fifteen, twenty, or thirty minutes, till they shall operate. Excess of effect is thus guarded against, in cases where the susceptibility may be greater than usual. Some of them are very uncertain in their dose, and especially require this precaution.

if intended merely to evacuate the stomach, they should be given with a considerable quantity of liquid, and aided, when they begin to act, by the free use of warm water, or warm chamomile tea.

if, on the contrary, a powerful impression is required upon the system at large; if it be wished to produce and keep up nausea, or strongly to compress and agitate the abdominal viscera by frequent retching; then the medicine should be administered with little liquid, and none should be given subsequently to aid its operation.

When the effects of an emetic are wanted purely in relation to the system, as for the relaxation, the shock, etc., it is generally best administered on an empty stomach; but the existing indications so often require its immediate exhibition, that it is for the most part necessary or advisable to give it, without reference to the question whether the stomach may be full or empty.

In cases of excessive emesis from an over-dose, the vomiting may be checked by first administering freely draughts of warm water, or some mild demulcent beverage, so as thoroughly to wash out the stomach, and then giving one of the preparations of opium by the mouth or rectum, or both, and applying a strong sinapism to the epigastrium. From thirty minims to a fluidrachm of solution of sulphate of morphia may be given by the mouth; or from thirty to sixty drops of laudanum, with a wineglassful of mucilage, by enema. The latter will generally be found the most effectual.