In very low cases of fever, it may be altogether improper to employ any brisk, or energetic, or actively depletory cathartic; but there are articles of the class, such as rhubarb and aloes, which, instead of weakening, if judiciously used really invigorate the patient, both directly by a somewhat tonic or stimulant influence, and indirectly by removing unwholesome and depressing matters from the primae viae. Hence, the system in typhus fever not unfrequently reacts, under the judicious use of cathartics of this character.

But what is to be said of enteric or typhoid fever, which is characterized by the coexistence of enteritis, and frequently of diarrhoea ? Nothing, certainly, can be more injudicious here than active purging. Yet, when there is, as sometimes happens, a disposition to constipation, or at least an insufficient action of the bowels, a very mild cathartic, such as castor oil in small doses, operates most happily by removing irritating matters. in such cases, a substance so bland in its action on the mucous membrane, is certainly less injurious than the accumulated, and often acrid and unwholesome secretions in the bowels.

In the inflammations, too, there are usually combined indications for cathartics; the two most prominent being depletion and revulsion, by which they act with great effect in these complaints. They are, indeed, among the remedies upon which most reliance is placed in the treatment, not only of the phlegmasiae, which are attended with fever, but of chronic inflammation also. Of course, the hydragogue cathartics are the most efficient, and of these the saline, as being at the same time refrigerant. in many inflammatory affections, it is highly probable that impurities of the blood aid in sustaining the local disease, and that cathartics prove useful also as eliminating agents. The only points which might render their use questionable in inflammation, are the existence of great debility, the complication of diarrhoea, and the location of the inflammation in the alimentary canal itself. Attention is undoubtedly due to all these modifying circumstances; yet none of them must be considered as absolutely excluding the use of cathartics. in debility, the selection of the cathartic must be made in reference to that condition; in diarrhoea, though energetic substances of the class might be forbidden, the milder are often called for to remove sources of irritation which serve to maintain the disease. in certain conditions of diarrhoea, few remedies are more efficacious than a dose of castor oil and laudanum, or a combination of magnesia and rhubarb.

In inflammation of the mucous coat of the stomach and bowels, cathartics are not called for as revulsives, yet they may and often do prove useful by removing offending causes, producing secretion from the congested vessels, and depleting from the portal circulation by promoting the secretory function of the liver. Hence, they have generally been considered as among the most efficient remedies in the treatment of dysentery.

In peritonitis, they are of more doubtful propriety; as, by the peristaltic movement they provoke, they cause the inflamed surfaces of different portions of the bowels to rub against each other, and cannot but aggravate the disease: producing, I think, more injury in this way than good by depletion, or by revulsion to the mucous membrane from the peritoneal. I am, therefore, not in the habit of using them to any considerable extent in this complaint, contenting myself with a thorough evacuation of the bowels in the early stage, so as to remove any feculent accumulation which might itself serve to provoke injurious peristaltic efforts, and afterwards with keeping the lower bowels open by enemata. in the peritonitis dependent on perforation, they should be avoided sedulously in all stages, and in any method of administration; the indication here being to keep the bowels as much at rest as possible.

There is another condition of inflammation of the bowels in which purgatives are liable to great abuse. The cases I allude to are those of enteritis attacking the whole thickness of the bowel for a, certain length, and thus paralyzing its movements, so as to produce obstinate constipation, which has not unfrequently been mistaken for obstruction, and treated accordingly with the most energetic cathartics, to the great detriment of the patient. The cathartics will not pass, and are, therefore, apt to be rejected by the stomach; while they aggravate the disease, by the excessive efforts into which they stimulate those parts of the inflamed bowel that are still capable of contraction. The indications are here to keep the bowel at rest, deplete generally and locally, apply blisters, and give calomel and opium internally. When the inflammation subsides, the bowels are opened spontaneously, or with the aid of very gentle cathartics.

The neuroses, dropsy, scrofula, cutaneous diseases, etc., also not unfrequently afford conjoint indications for cathartics; but the principles already stated will be sufficient for general guidance in their use; and it is wholly unnecessary to go through all the categories of disease, and point out minutely the several circumstances in each which may call for, discourage, or forbid the use of these medicines.