1. The capacity of leeches for drawing blood differs considerably. The common English or speckled kind draws from f3j, to f 3ij., not including that which flows subsequently. The Indian leech draws from f3j. to f3iij., and the Hungarian variety is supposed to draw even more.
2. In order to make leeches bite readily, thoroughly cleanse the surface of the skin with soap and water, and then dry it. This is particularly necessary if an embrocation has been previously employed. If they will not bite, one of the following plans may be tried: - 1, remove the leech from the water and roll it for fifteen or twenty minutes in a warm dry cloth; 2, lower the temperature of the surface of the skin; 3, smear the surface with cream, or sugared milk; 4, roll the leech in porter; 5, make a puncture with a lancet, and smear the blood over the surface: this is often effectual. It should also be remembered that the fumes of sulphur, vinegar, or tobacco in a room will often effectually prevent leeches from biting at all.
3. To make leeches bite on particular spots, take a piece of blotting-paper and make in it as many small holes as there are leeches, the holes corresponding with the spots on which it is desired to apply the leeches; they are then to be covered over with a tumbler. The animals, finding themselves on a rough surface, creep about till they come to the openings in the paper, when they instantly bite the exposed points of the skin. The blotting-paper is easily removed by being moistened.
4. Leeches should never be applied to the tonsils, orifices of the uterus, rectum, &c, excepting by means of a glass properly constructed for the purpose, otherwise they may get beyond reach and do much mischief. Should, however, such an accident occur, a strong solution of common salt, either by mouth, or enema, or injection, as the case may require, will be sufficient to dislodge them.
5. Great care is necessary in the application of leeches to infants and young children. The loss of a small quantity of blood produces a more sensible effect upon them than a proportionate quantity upon adults; and it should be borne in mind that, on account of the thinness of the skin and the greater vascularity of the subjacent parts, a leech will abstract a greater quantity of blood from a young child than from an adult. Three leeches, bleeding well, are a full bleeding for a child one year old, labouring under acute inflammation; and if one be added for each year of the child's life up to five, a fair average may be obtained. Dr. Ramsbotham suggests, that when it is necessary to apply leeches to children, they should, if possible, be placed on some part of the body where the bone is near the surface, so that counter-pressure may be conveniently made, in case of excessive hAemorrhage. Dr. Garrod advises that leeches should not be applied to an infant towards evening, unless quite unavoidable, lest hAemorrhage continue unchecked through the night.