Cupping, a method of local abstraction of blood, through small scarifications, by the assistance of bell-shaped glasses exhausted of air. When the object is merely to draw blood to a part, for purposes of revulsion, the exhausted glass is used without incision of the skin; it is then called dry cupping. The old method of exhaustion was by burning a bit of paper or a few drops of alcohol in the glass, which was then immediately applied to the skin. A more convenient and certain exhaustion is now obtained by means of a small syringe attached to the cup; the risk of burning the patient is avoided, the locality may be carefully selected, and the pressure accurately graduated. If, after the blood is drawn to the part by a dry cup, it is desirable to deplete the vessels, the skin may be cut by a bistoury or lancet, or by an instrument called a scarificator; this consists of a square box of brass, in which are mounted from 6 to 16 blades, which are set and discharged by a spring; the depth of the incision can be exactly regulated, and the action is so instantaneous that very little pain is felt. From these little wounds the pump draws into the glass from 1 to 5 oz. of blood, according to its size.
After sufficient blood has been drawn, a piece of adhesive plaster is put on to close the punctures and prevent suppuration. Dry cupping has been used with advantage in diseases of the brain and lungs, applied in the first case to the nape, shoulders, and arms, and in the second to the back and base of the chest; also in diseases of the eyes. The amount of blood taken by cups can be well measured; they are less disgusting than leeches, quite as effectual when they can be applied, and not liable to be followed by inflammation of the wounds; they are employed either after or in place of general bleeding. In pneumonia, pleurisy, and abdominal inflammations, and various local affections, they are applicable when venesection would be out of the question, and are generally preferable to leeches. Cups may be used to prevent the absorption of the virus in poisoned wounds and bites. M. Junod, in France, in 1838, invented a monster apparatus, capable of receiving the whole lower extremity, in which by means of a pump the limb could be either compressed or placed in a comparative vacuum; the derivative and revulsive effects of this apparatus were energetic, amounting if desired to the production of syncope.