Emetics

Some of the agents in this group produce vomiting by virtue of a local action on the stomach, and do not affect this viscus when introduced elsewhere. These may be entitled Emetics by Local Action. There are others which cause emesis when they enter the blood at any point—Systemic Emetics. The first sub-group of emetics make an impression on the gastric nerves, and an action is at once instituted for their expulsion. The process consists in the transmission of the peripheral irritation to the spinal center, the generation of a motor impulse, and the consequent action of the nervous and muscular apparatus concerned in the mechanism of vomiting. The systemic emetics produce their effects through the intermediation of the blood, and the vomiting is only one of the results of the disturbance introduced into the functions of the nervous system.

Emetics By Local Action

The most important of these are:

Cupri sulphas, sulphate of copper.

Zinci sulphas, sulphate of zinc.

Hydrargyri sulphas flava, yellow subsulphate of mercury.

Alumen, alum.

Sinapis, mustard.

Scilla, squill.

All of the members of this group have been discussed in other parts of this work, except mustard and squill, and the consideration of these will be more appropriate elsewhere. It is necessary, however, in this place to indicate the nature of the action, the cases to which they are adapted, and the mode of administration of the more important of the emetics belonging to this division.