When the leech has dro pad off it should be seized by the tail or medal esd, and striped beta een the finger and thumb, so as to cause It to disgorge meat of the blood. It is proper to allow it to retain a third of the bloat This is preferable to applying salt or vinegei to the mouth. It should then be placed in many successive froth waters, and it may perhaps survive, and after many menthe be again fit for use. In winter, it should be put at first into tepid or lukewarm water ; for though e&l•GGoled itself, its body lute been filled with blood of a teroperaturo of nearly, or perhaps above, 10u* Fehr. .
When no expedient Is had recourse to, in order to maintain the thew of blood, it generally stops spontaneously ; but in some cases it con tinues much longer than is proper. Where the blood is either deficient in coagulating power, as happens in many weak persons, or when it is in a very alkalesceut state, and the albumen in too dilute a condition, or owing to the very vascular state of the skin of children, the haemo rrhage is often troublesome, and in the case of children, who do net bear well the loss of a large quantity of blood, sometimes fateil The object of any remedial means is to form a coagulum, or plug, at the mouth of the bleeding vessel& A weak solution of crearote applied to the part will generally effect this, or felt scraped from a hat, or gum in powder, or flour, or the dust of the puffball (Iyeoperdon or bovista , or the application of a compress and bandage, tying a ligature, or touching the wounds with lunar caustic. The patient should at the mine time drink a saturated solution of alum, or take dilute sulphuric acid out of very cold water.
9 he increasing scarcity of leeches renders their preservation and propagation objects of primary importance. The death of a vast number of leeches is occasioned by errors in the method of keeping them. Though aquatic animals, it is not enough that they be supplied with water. They breathe by their entire surface, and are accustomed to change their skin every four or five days. Their body is covered, like that of all animals and plants which inhabit the water, by a slimy or muctlaeinons fluid, which not only enables them to glide through the water, but keeps an aerial stratum in close contact with their respiring surface. When present in a limited degree, this mucous becrenioo is highly serviceable to them ; in excess, it is cieetnictive. It i. impossible for them to diminish it when it has accumulated, or to denude themselves entirely of their old skin, in water only. They must have some resisting body to creep over or through in order to accomplish this object. Sortie leech-timbers keep clay at the bottom of the troughs. lend though this is useful as a mater.al in which the leeches can burrow In warm weather (by which they arc always more injured than by cold, if riot Intense; and it is their habit to retreat to the deepest waters of their native rivers or ponds in summer), it. is inadetpuste to the end. The beat method seems the following recom mended by Fee ; Into a marble or atone trough a layer of seven inches of a mixture of mon, turf, and charcoal of wood is to be put, and some small pebbles plated above it ; at one extremity of the trough, and midway tetween the bottom and the top. place a thin plate of marble p:crced with numerous small holm, upon which there should rest a stratum of moss or portions of the squiseturn palustre, or horsetail, firmly compressed by • stratum of pebbles. The trough to be replenished with water
only so high that the moss and pebbles should be but slightly moistened. A cloth 111 to be kept over the mouth of the trough. This is imitating as near as possible their natural condition, and the charcoal not only aids in keeping the water sweet, but appears to prevent the leeches being attacked by parasitic animals, to which they are very liable. The water should be changed about once a week, and more frequently In warm weather.
Leeches have not been observed to propagate when kept in small bodies of wster, but in large reservoirs, having a body of turf and maims, and the eider well furnished with clay, in which to deposit the cocoons, Dr. Noble of Versailles has succeeded in procuring young man It has ales been ascertained in France that leeches which have been used, if rotund to their natural haunts, propagate abundantly, and aloe become ca able of being Arvin applied after eight or twelve months' stay in these ongtnisl quartets.
The great esCilt to which the trade In leeches is caniod on renders attention to this subject of paramount importance. Four only of the Principal dealers In London used to import 7,200,000 annually, and In Paris 3,000,000 are wed. But in England the consumption of leeches is now (1860) very greatly diminished.
Leeches have sometimee been swallowed; and in Syria and other places a small leech is sometimea drank with the waters of the pools, and by adhering to the throat causes great suffering. Salt or vinegar is the beet means of dislodging them. Beside these Syrian leeches, there is in Ceylon, the lower range of the Himalayan Hills, Batavia, and other islands a land-leech (lI.esiQdipsa Ceyl mica, Boac.) which is of a formidable nature, not from its size, " for they are only about an inch in length, and as fine as a common knitting-needle ; but capable of distension till they equal a quill in thickness, and attain a length of nearly two inches.. Their structure is so flexible that they can insinuate themselves through the meshes of the finest stocking, not only seizing on the feet and ankles, but ascending to the back and throat, and fastening on the tenderest parts of the body. The coffee planters, who live among these pests, are obliged, in order to exclude them, to envelope their legs in • leech-gaiters' made of closely woven cloth. The nativea smear their bodies with oil, tobacco a lies, or lemon-juice; the latter not only serving to stop the flow of blood, but to expedite the healing of the wounds. These creatures are gregarious, and make their attacks in concert, with such well directed tactics, that it is difficult to elude them." 'Ceylon,' by Sir J. E 'raiment, vul. f. p. 301 of 2nd edition. In the same island, a cattle-leech ( !Iasi ipsis jean/lure) is most formidable to cattle which go to drink in the pouc; frequented by them. They are very insidious, and their bite at first gives little pain, but the consequences are often fatal. (lbid p. 30(i.) These aro probably the same as are mentioned by I'lioy (' Hist. Natur.' viii. 10) as distressing the elephants.
(Johnson On the Medicinal Loch; Brandt and Hatzeburg, Garene Daritellurig der nitre ; and Mr. Pereira's! Mat. fled.)