They form a very valuable resource, either where the patient is unable to swallow, or where it is of importance speedily to unload the lower intestines.
16. Cathartics should not ordinarily be given so as to interfere with the regular rest.
5. Passive dropsies, particularly Hydrothorax, occurring in old persons or broken-down constitutions.
Inflammation. " Purging," observes Dr. Watson,* " is an expedient which, in cases of violent inflammation or high general fever, should scarcely ever be omitted. To keep the bowels what is called open forms, indeed, a part of the antiphlogistic regimen; but in acute inflammatory diseases, active purging is of very great service. These two points are gained by it: the intestinal canal is freed from accumulated faeces or other matters, which, by their bulk or their acrimony, might prove irritating; and, at the same time, depletion is carried on by means of the serous discharge which is produced from that large extent of mucous membrane. There are some cases of inflammation in which the operation of purgative medicines is of especial benefit, as in inflammatory affections of the Head, either external or internal, of which part these medicines assist or cause depletion in a very sensible manner. We have an illustration of this in the paleness of the face, which often, during health, accompanies the action of a brisk cathartic. The usefulness of repeated purgatives is less distinctly seen in inflammations situated within the Thorax, although in these cases, also, they are often highly beneficial. They are efficient remedies in all inflammatory conditions of the Liver. But when inflammation has fastened upon the Stomach or Bowels themselves, although it may be indispensable that they should be unloaded of their contents, which are often composed of irritating, ill-digested food, and of morbid secretions no less teasing and hurtful, the propriety of going beyond this point is extremely questionable." Dr. Watson adds, that "much harm is often done by pressing the inflamed alimentary canal with active purgatives."
* Lectures, vol. i. p. 230.
3024. Fevers, In Intermittent, Remittent, Bilious-remittent, and Continued Fevers, it is a point of first importance to administer, at the outset of the disease, a brisk purgative (Calomel or Croton Oil), in order thoroughly to remove all crude and ill-digested matter from the intestines, and to act as a depletive in the manner described in the last section. Saline purgatives seem peculiarly adapted for these cases, and may be repeated according to the urgency of the symptoms, or as the circumstances of the case may require. Dr. J. Johnson* considers that they operate in two ways: 1, by establishing a change from torpor of the intestines to a brisk peristaltic motion, whereby the blood, which has been shown to accumulate in the portal circle, is propelled forward, and the biliary as well as other secretions are increased; 2, by re-establishing the sympathetic influence which the internal surface of the alimentary canal exerts on the cutaneous surface of the body; for although drastic purging will check profuse perspiration, yet, where torpor pervades both the internal and external surfaces of the body, a restoration of the functions of the former contributes to the same event in the latter. They are more adapted for the active fevers of tropical countries than for the typhoid fevers of temperate climates. In Typhoid (Enteric) Fever, where ulceration of Peyer's patches is suspected, purgatives should be avoided; or, if administered, the very mildest should be selected. They are hardly admissible in the adynamic forms. Indeed, in these latter, Dr. Murchison considers that the natural history of the disease appears to him to contra-indicate laxatives. Both with regard to Typhus and Typhoid (Enteric) Fever, he states that he has seen alarming prostration follow the use of purgatives. Their use requires the greatest caution.
3025. In Puerperal Fever, Puerperal Peritonitis, cathartics have been advised by Denman, Gordon, Armstrong, Hey, Hulme, and Murphy; and have been prohibited by Clarke, Campbell, Thomas, Baglivi, and others. The weight of evidence is in favour of the use of mild, unirritating aperients. Dr. Ferguson judiciously advises their being combined with Dover's powder or Henbane, in order to prevent tormina, which are often the precursors of Metro-peritonitis.
* On the Influence of Tropical Climates, 6th Ed., p. 82.
On Fevers, pp. 264, 569.