Purgatives, or Purging Medicines, are such as evacuate the crudities of the bowels by stool, and which are sometimes called Cathartics.
Purgatives constitute one of the most important branches in the catalogue of drugs : they differ from Laxatives only by the greater expedition with which they operate.— As we state the most useful of such drugs in alphabetical order, it would be needless to repeat the proper doses, or the occasions on which they are employed. These medicines, however, ought to be sparingly administered; for they vellicate or stimulate the fibres of the stomach; and, by abrading the lubricating fluids, the fibres of the interior vessels, and the muscles of the abdomen, become more frequently and unnaturally contracted. Farther, drastic purgatives should be taken with still greater caution; as their stimulating parties often powerfully a celerate the circulation of the blood; an effect, which, in robust constitutions, may sometimes be of service; but, in weakly or nervous persons, especially those of sedentary occupations, such medicines are generally productive of bad consequences, and often lay the foundation of a confirmed costive-ness.
For those readers, who are apt to meddle with physic, on the slightest occasions, we shall lay down the following rules : 1. Purgatives ought to be taken only in cases where the crudities are disposed for evacuation, and their tur-gescence obviously tends downward : this circumstance may be ascertained, in acute diseases, by the weight and distention of the abdomen ; flatulency ; rumbling and pain in the lower belly 5 and an inclination to stools. 2. They must be cautiously avoided, where Nature appears to make an effort to vomit. 3. Likewise, in great weakness of the bowels. 4. To healthy individuals, whose feces are indurated, drastic purges are exceedingly detrimental; because their disposition to Costiveness (which see), is the best proof of their vigorous habit. 5. If such remedies become necessary, they should be given in the morning, when the first passages are empty ; in diseases, during the intermission of paroxysms. Lastly, all nourishment, but particularly solid food, must be withheld previously to the operation of the medicine ; nor should the patient be allowed much drink, till the purgative actually begin to produce its effect. Mucilaginous drinks, such as gruel, barley water, etc. are the most proper lor this purpose 3 but, if the bowels are not opened by an ordiG nary dose, intead of resorting to additional drugs, it will be more safe to inject laxative Clysteks, which we have already stated under that head.