_Carte’s Tourniquets_ (fig. 101) are employed to control and diminish the flow of blood through an aneurism. They are intended to be worn for several days, and are fitted with many contrivances for obtaining a continuous pressure on the artery without completely arresting the flow of blood. They are always used in pairs; in the figure, one presses the external iliac on the pubes, the other the femoral artery. The first is fastened to the body round the hips, the second round the thigh. They are constructed as follows: an arm attached to a pad reaches round the limb to the artery, over which it supports a ball and socket joint turning in any direction, but fixed by a screw clamp. This joint has a long screw carrying the compress down to the artery. There is a little play of the screw in the ball of the joint, controlled by india-rubber bands, that the compress may yield slightly before the arterial pulse. In the solidification of an aneurism by this means, the flow of the blood is intended to continue; hence the current through the vessel need not be completely obstructed by the pressure of the tourniquet, and the elastic bands prevent that pressure from becoming insupportable. When the tourniquets are applied, the patient must lie on a flat hair mattress, have his limb well washed and dried, lightly but evenly bandaged, and somewhat raised. If the thigh is hairy it should be shaved where the pads will press, and dusted with powdered French chalk. The tourniquets are next adjusted, as seen in fig. 101; the patient is taught to change the pressure when it grows irksome, by screwing down the second pad, and then releasing the first. _To improvise a Tourniquet._—A tourniquet may readily be formed on emergency from a handkerchief, a stone, and a stick. Fold a stone the size of an egg in the middle of a handkerchief, lay it over the main artery, tie the ends of the handkerchief round the limb, slip the stick underneath and twist it round, till the tightened handkerchief draws the stone on to the artery and arrests the flow of blood (see fig. 102). [Illustration: Fig. 102.—An improvised tourniquet.] =Fumigation.=—Mercurial vapour baths are contrived in various ways. The following plan succeeds perfectly well when the whole surface of the body is to be exposed to the vapour (fig. 103). [Illustration: Fig. 103.—Mercurial fumigation.] [Illustration: Fig. 104.—Lamp for fumigating.] _Apparatus._—A Langston Parker’s lamp made by Savigny and other instrument makers. In this a spirit lamp, holding the required amount of spirit is protected in a cage, on the top of which is a receptacle for the calomel, and a small saucer for water (fig. 104). The flame beneath boils the water and volatilises the calomel. Water is added, because the calomel vapour, when associated with steam, acts more efficiently than with dry air.