3. By producing Catharsis, and thereby increasing the action of the Exhalants directly, and that of the Absorbents indirectly.
1. Elaterium.
2. Jalap, &c. &c.
C. 1. Of Medicines which act Primarily on the Urinary Organs.
1. By stimulating the secreting vessels of the kidneys, by actual contact.
a The substance not undergoing any decomposition in transitu.
It is easy to imagine that any substance which is capable of entering the current of the circulation, and of stimulating the kidneys by a direct application to their secerning vessels, may occasion a more copious urinary discharge; in this manner the different saline[[157]] preparations, Potass, Soda, Nitrate of Potass, &c. are brought to the kidneys in the course of the circulation, and exciting the vessels to an increased action, promote the secretion of a larger proportion of watery fluid from the blood, in consequence of which, the absorbents are indirectly stimulated in order to supply the deficiency, and in this manner dropsical swellings are reduced.
Water, as a simple diluent, will promote the action of the kidneys, and it is very judiciously remarked by Dr. Cullen, that by withholding the use of fluids in dropsy, you will diminish the quantity of fluids secreted, and allow the secretories of the kidneys to fall into a state of inactivity and collapse. This is a sufficient answer to those who defend the practice of enjoining an abstinence from all drinks in dropsy.
b. The diuretic remedy undergoing decomposition IN TRANSITU.
The digestive organs appear to possess the power of readily decomposing all saline compounds into which vegetable acids enter as ingredients, and of eliminating their alkaline base, which, being in the course of the circulation, carried to the kidneys, excites them into action, and promotes the excretion of urine; and it is probably in this way that the Acetate, Citrate, Super-tartrate, and other analogous combinations of Potass and Soda prove diuretic: on the other hand, it is equally evident that salts containing the mineral acids are not under the control of the decomposing powers of the chylo-poietic organs, and consequently do not undergo any changes in transitu, although some of these salts, as I have just stated, especially the more soluble ones, are absorbed entire, and prove diuretic. Sulphate of Potass, from its insolubility, is not readily absorbed, and its composition will not allow the developement of its base; we perceive therefore that it has not any tendency to produce an influence upon the urinary secretion.