1. the high frequency current is unipolar, that is, does not require a complete circuit. 2. glass does not insulate the high frequency current as it does ordinary electricity. 3. the high frequency current generates enormous quantities of ozone during its flow. 4. the current does not produce any pain. 5. the high frequency current produces a cellular massage. The contractile effect is expended upon the individual cells making up the tissues, instead of on individual muscles. If a sedative effect is desired, keep the electrode in contact with the part; if a stimulating effect is desired, hold the electrode away from the surface; the farther away, the longer the spark. A uniform spark of any length can be produced by administering the current through layers of toweling, or through the clothing; the length of the spark depends upon the thickness of the layers. The use of the high frequency current in surgery is limited to sprains, stiff joints, neuritic pains, and adhesions due to inflammatory exudates. Fulguration for the destruction of growths is obtained by employing a pointed metal electrode. +RUBEFACIENTS+ +Rubefacients.+ These are agents which revulse by causing congestion of the skin: +1.+ +Turpentine.+ A few teaspoonfuls of oil of turpentine sprinkled over a piece of flannel wrung out of hot water, applied to the skin and covered with oiled silk or dry flannel, constitutes the turpentine stupe. Twenty minutes is the maximum for this application. +2.+ +Mustard.+ Mustard flour (the black being the stronger), mixed with tepid water into a paste, spread thinly on a piece of muslin or paper, and covered with gauze or thin cambric, is an excellent counterirritant. Few skins will bear pure black mustard for more than ten minutes. Mustard, diluted one-half with wheat or corn flour, and allowed to stand for twenty minutes, should be the maximum strength for application, because blistering must be avoided, that produced by mustard being specially painful. After removing a mustard plaster, greased lint should be applied. +3.+ +Mustard Foot-Bath.+ A mustard foot-bath consists of one or two tablespoonfuls of pure mustard in a bucket two-thirds full of water at 105°F; the feet may be kept in this for about twenty minutes, a blanket being thrown around the limbs, and including the bucket, to retain the heat. Revulsives must be used with caution in cases of shock or coma, lest impaired vitality or sensation to pain result in extensive sloughing of the skin. +CAUTERIES+ +The Actual Cautery+ is used in the form of variously shaped irons, hatchet-edged, round, or olivary, fitted into wooden handles, and heated in a charcoal furnace. As a counterirritant, the iron should be heated only to a dull red heat, and should be quickly drawn in parallel lines, about one inch apart, over the skin, avoiding all bony prominences. Compresses wet with cold water, or with some antiseptic lotion, may then be applied.