MATERIA MEDICA.

THE agents employed in the treatment of diseases are denominated REMEDIES, and the branch of medicine which is devoted to their consideration is termed MATERIA MEDICA. Remedies may be divided into Hygienic, Mechanical, Imponderable, and Pharmacological agents.

HYGIENIC REMEDIES are usually treated of in works specially devoted to the subject.

PART I.

MECHANICAL REMEDIES.

MECHANICAL REMEDIES belong chiefly to Surgery. A few agents of this class are, however, employed in the practice of medicine, and are included in the Materia Medica. They are blood-letting (general and local), setons, issues, bandages, friction, acupuncture, and aspiration.

1. GENERAL BLOOD-LETTING is performed principally by venesection or phlebotomy, which is usually practiced on the mediancephalic or basalic veins of the arm-sometimes also on the external jugular and other veins. Arteriotomy is occasionally resorted to, on the temporal artery, in cerebral affections.

Blood-letting is employed to moderate vascular excitement, reduce inflammatory action, relieve congestion, allay spasm and pain, relax the muscular system, promote absorption, and arrest hæmorrhage; and for these purposes it has long been con

sidered a valuable therapeutical resource. So powerful and exhausting an agent is, however, always to be resorted to with caution and discrimination; is not to be unduly repeated, even in inflammatory cases; and is seldom or never proper in diseases of a typhoid tendency, or where a tubercular diathesis is suspected, or in extreme infancy and old age. It is indicated in inflammations of sthenic type occurring in robust adults, and accompanied by a full, bounding, tense pulse, and should only be resorted to early in the case, before effusion has taken place.

2. THE LOCAL ABSTRACTION OF BLOOD is practiced by means of leeches, cups, and scarifications. The leech (hirudo) is an annulated aquatic worm, with a flattened body, tapering towards each end and terminating in circular flattened disks, which is found throughout Europe, America, and India. The European leech (h. medicinalis, termed also sanguisuga officinalis) is of a blackish or grayish-green color on the back, from two to three or four inches in length, and is characterized by six longitudinal dorsal ferruginous stripes, the four lateral ones being interrupted or tessellated with black spots. It draws about half a fluidounce. The American leech (h. decora) is usually from two to three inches long, and is of a deep green color, with three longitudinal dorsal rows or square spots. Both the imported and indigenous leech are employed in this country, but the latter makes a smaller incision, and is preferable in infantile cases. It takes about a fluidrachm. When the discharge of blood from leech-bites is excessive, it may be arrested by pressure, by compresses of lint, the application of alum, creasote, solution of iron subsulphate, and other styptics, or by cauterizing the wound with silver nitrate or a red-hot probe; and if these means fail, the lips of the wound may be sutured.

In the operation of cupping, cupping-glasses and a scarificator are employed. The removal of atmospheric pressure, by the application of glasses partially exhausted of air, produces a determination of blood to the capillaries of a part, and it is afterwards readily drawn by scarification. When blood

MECHANICAL REMEDIES.

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is not abstracted, the operation is termed dry cupping, and is a valuable revulsive agent. The topical abstraction of blood by leeches and cut cups combines the advantages of depletion and revulsion. Leeches are employed in external inflammations, in situations where cups are inadmissible, and in infantile cases. Cups are generally preferable in internal inflammations, from their more decided revulsive influence. When blood is drawn by leeches, its continued flow may be promoted by the application of warm fomentations to the wounds.

Scarifications are slight incisions made in inflamed parts, to relieve the engorged capillary vessels; they are often employed with benefit in inflammation of the conjunctiva and of the tonsils.

3. SETONS (setacea) and ISSUES (fonticuli) are employed when a permanent counter-irritant effect is desired. A seton is established by passing through the integument a seton-needle, armed with a skein of silk; or a piece of tape or a strip of sheet-lead may be used for the purpose. An issue is made with a cauterant, usually potassa; and after the slough has separated, a discharge is maintained by the introduction of an issue-pea, for which purpose a common dried pea is used, or a dried unripe Curaçoa orange, or a small round ball made of Florentine orris-root. Setons and issues are not much employed.

4. BANDAGES are employed, in the practice of medicine, to promote the absorption of dropsical effusions. For the same purpose strips of adhesive plaster may be applied to the chest, in chronic pleurisy and empyema, in the manner in which they are employed in the treatment of fractured ribs.

5. FRICTIONS are useful as revellents and as local stimulants. They may be employed either with the dry hand or with horsehair gloves, or with liniments. The latter, applied with a sponge, are serviceable in lumbago, sciatica, chronic rheumatism, and affections of the joints; rubbed on the chest in bronchitis they often afford relief.

6. ACUPUNCTURE consists in the introduction into the body of fine, well-polished, sharp-pointed needles; they are intro