The leech is put in a little glass when applied to the gums or the cervix uteri, and held against the part he is to suck. If the leeches do not bite readily the part should be smeared with blood or warm milk, and the leeches put into lukewarm water a few minutes; immersion in small beer is also said to stimulate them to bite. If the bites bleed longer than is desired, they may be stopped by pinching the skin between the finger and thumb, wiping the bite thoroughly dry, and filling it with a little bit of amadou or fine sponge, soaked in solution of perchloride of iron; a larger piece of amadou is placed over the first, and the whole compressed with a turn of a bandage or long strip of plaster. If this fails, a sewing needle may be passed through the skin beneath the floor of the bite, and the bleeding surface constricted by twisting a thread round it under the needle. Leech-bites should never be left bleeding, especially in children, for a dangerous amount of blood may be lost from them in a few hours. =Tents= are instruments made of some substance that enlarges as it absorbs liquid; they are employed to dilate apertures of sinuses or natural passages, as the cervix uteri, &c., and are generally short rods 2 to 3 inches long, and 1/10 to ¼ inch in thickness, made of a whalebone stem, wound round with compressed sponge, which is smeared with wax to keep it in shape. Slips of gentian root, or of laminaria digitata, which rapidly enlarge as they imbibe moisture, are also employed for this purpose. =Setons= are strips of varnished calico, 6 or 8 inches long and ⅓ broad; a thread is fastened to each end, which are tied together while the seton is worn. It is employed to excite irritation either along the course of a sinus, or in some superficial situation, as the nape of the neck, to relieve congestion of internal parts. In sinuses, a few threads of silk usually produce the required amount of irritation. =Chassaignac’s Drainage-tubes= are a form of seton; they are india-rubber tubes of the calibre of a wheat straw, of any requisite length, and perforated with holes at frequent intervals; they are carried into the cavity to be drained, by hitching the prong of a forked probe, made for the purpose, through one end of the tube and thrusting it along the sinus, or across the abscess. The skin is then incised over the further end of the sinus to bring the probe out, and the ends of the tube are tied together. The advantages of these tubes are, the small amount of irritation they provoke, and the ready exit furnished for the matter along their interior.