Diuretics, a term applied to those medicines which increase the secretion of urine in the kidneys. Their operation consists in promoting the circulation of the blood towards the renal arteries, rendering that vital fluid more serous, and at the same time stimulating the secretory organs.

The use of diuretics, in general, is indicated by the following circumstances : 1. An interrupted or diminished discharge of urine: but, as this complaint may arise from a great diversity of causes, such as spasms, acrimony of the fluids, relaxation of the solids, plethora, etc. great circumspection is necessary in the choice of medicines properly adapted to the nature of the case. 1: A natural tendency of the con stitution, to evacuate the morbid matter of a particular disease, by this passage : the symptoms of which are, a frequent inclination to make water; a dark, turbid, and copious urine. 3. An earthy, alka-. scorbutic quality of the fluids. 4. An abundance of aqueous humours in the body, in general; or an extravasation of them, in particular parts. 5. Alocalaccumulation of impurities in the urinary passages.

On the contrary, diuretics should never be resorted to in the following cases: 1. In diabetes, or an immoderate and long-continued evacuation of mine, 2. When this fluid is mingled with blood. 3. In inflammations of the kidneys and bladder. 4. In violent spasms, when there is reason to apprehend that stones are confined, or other organic defects prevail, in the urinary canal. 5. In those profuse states of perspiration, termed critical. 6. When the patient's body is already deficient in aqueous humours.

In the same proportion as we make use of thin, diluent liquors, the quantity of urine may be either increased or diminished : frequent drinking of such watery beverage is, therefore, one of the mildest diuretic remedies. This effect: may be considerably promoted by the addition of such substances as specifically act: upon the kidneys. To this class belong all the mineral waters containing saline ingredients, as well as the juices of mild summer fruit mixed with water, and particularly the sap extracted from the birch-tree.

Those, who are under the influ-' ence of diuretic medicines, ought to observe a cool rather than a warm regimen; because heat promotes perspiration, and lessens the secretion of urine. During the use of such remedies, considerable benefit may be obtained by conjoining thern with those articles of vegetable nutriment, which naturally operate on the kidneys. Of this kind are the tops of asparagus and hops, the sweet cicely, lettuce, parsley, celery, all the subacid fruit, such as cherries, currants, raspberries, strawberries, grapes, mulberries, apricots, peaches, etc. — Beside these, we possess various and more powerful diuretics among plants, for instance, the horse-radish, onions, and garlick, neither of which, however, ought to be indiscriminately taken. One of the most efficacious remedies of this description, is the expressed juice of the common radish (Raphanus sativus, L.) mixed with sugar to the consistence of a thin syrup, and taken in doses of one or two spoonfuls, every three or four hours, or oftener.