LEECHING, or the application of leeches (q.v.), for the purpose of abstracting blood, is preferable to venesection or cupping in many forms of disease; as, for example-1. In local determinations of blood, unattended with febrile symptoma, as in acute inflam mation of the female breast, when the pressure of the cupping-glass would cause intense pain. 2. In abdominal inflammations, especially in peritonitis; (q.v.), the application of leeches is often preferable to general blood-letting,.pa•tieula•ly in patients of a weak constitution. 3. In various organic affections of the heart and lungs, leeching often affords great relief. Indeed, there are few diseases in which loss of blood is required, excepting erysipelas, in which the application of leeches is objectionable; although it is inexpedient, as compared with venesection, in those cases in which it is desirable to make an immediate impression on the disease (as in peritonitis in robust persons), or where the disease is very rapid and fatal (as in croup).
In the diseases of infants and young children, leeches must be applied with caution. Infants are sometimes completely blanched by the application of one or two leeches, and a case is recorded by Pelletan in which six leeches applied to the chest proved fatal to a child aged 6 years. In applying leeches, the part should be thoroughly cleaned, and the leeches, atter being dried by rubbing them in a clean linen cloth, should be placed in an open pill-box or in a wine-glass, and applied to the spot at which it. is desired that they should attach themselves. When it is wished to affix a leech to the inside of the mouth, it.is placed in a narrow tube called a leech-glass. When the animals will not attach themselves readily, they may sometimes be induced to bite by moistening the part with milk or blood.
The quantity of blood which a leech is capable of drawing may be estimated at an average at about a dram and a half, although occasionally a leech will abstract between 3 and drams; and this quantity does not include that lost after 'the animal has fallen off, which is frequently, especially in children, very considerable. In order to cause the leech to disgorge the blood, the usual practice is to applysalt to its body.
When the leeches have fallen off, it is usually desirable to promote to some extent the flow of blood from their bites, and. this is readily done by the application of warm fomentations or poultices. The bleeding generally stops spontaneously after a short time; if it goes on longer than is desirable, mere exposure to the air, or the application of the fluff of a hat, or of a bit of cobweb, will usually check it, the ft brine of the blood coagulating on the applied filaments, and forming a small clot. If these means fail, a little cone of lint should be inserted into the bke, over which a compress should be laid and a bandage applied; or the bite should be touched with a stick of nitrate of silver (lunar caustic) scraped to a point.
Leeches, when applied to the mouth or interior of the nose, have been occasionally swallowed, and have given rise to very unpleasant symptoms. The best treatment in it ease of this kind is to prescribe wine—half a glass, or even a glass, every quarter of an hour—which will speedily destroy the leech. A moderately strong solution of common salt would probably exert a similar fatal action on the animal.