When the proper number have been applied, they should be left quite alone, or they are apt to unfix, and, wandering about, are of no further use. When they have sucked their fill, they generally drop off, and should then be put in a plate with a _little_ salt, which quickly makes them throw up the blood; and, as soon as they have emptied themselves, they should be put into plenty of fresh cold water, so that they may get free from the salt, for if left in it, or if _too much be put on them_, they contract violently, and die almost immediately. After the leeches have come off, the bleeding from the wounds is to be encouraged, by first quickly sponging off whatever clotted blood there may be, and then covering the part with a warm bread-and-water poultice, which must be changed every half hour, so long as it may be thought necessary to keep up the bleeding. This is much better than leaving the surface exposed, and mopping with a warm sponge, which is very fatiguing to the patient, besides exposing him to the danger of taking cold. One disadvantage in the use of leeches is the great uncertainty, as to whether too little or too much blood is obtained by them. Getting too little blood, however, is a matter of very trifling consequence, in comparison with getting too much, for instances have occurred in which leech-bites have continued bleeding for days in grown-up persons as well as children, bringing them into a very dangerous condition; nay, there is no want of well-authenticated cases of death caused by bleeding leech-bites, and that, too, in the course of twenty-four hours. The cause of this serious business is sometimes a peculiar constitution, in which the blood will not clot with sufficient firmness to stop the bleeding; or it may be some little artery has been wounded by the bite in such a way that it cannot be stopped by a clot of blood. If, then, a leech-bite continue bleeding for some hours, and the person, more especially if an infant, begins to be very faint, and the countenance and lips pallid and cold, like marble, no time must be lost in stopping the bleeding.