EMETICS, substances which are administered for the purpose of producing vomiting. They are usually regarded as of two varieties, viz., those which produce their effect in virtue of their absorption into the blood and consequent influence upon the nerve centres, and those which act topically on the mucous membrane of the stomach, giving rise to vomiting as the result of reflex action. The former class of emetics are slower in their operation and are attended with much greater depression of the system and antecedent nausea than the latter, the action of which is prompt. The use of emetics in medicine is comparatively rare, although at one time they were often resorted to in the early stages of acute diseases, such as fevers and inflammations, with the object of cutting them short. Their power, however, to accomplish this is more than questionable. Among the purposes for which emetics are employed are the following—to empty the stomach in certain cases of poisoning, such as by narcotics or where indigestible substances are giving rise to disturbance which calls for their removal, and to clear the air passages of obstructions, as in certain cases of bronchitis or croup, where the respiratory tubes become filled with morbid material which threatens death by asphyxia, and which cannot be dislodged by coughing, For both these purposes the stimulating emetics are to be preferred, such as the sulphates of zinc and copper, or, where these are not available, mustard stirred into water. Again, emetics are employed in producing, short of their emetic action, a certain degree of nausea and consequent relaxation during the early stages of acute inflammation in strong persons, and for this purpose the more depressing emetics are resorted to, such as antimony, ipecacuanha, apomorphia, ...