CLASS VI.—WORMS.
270. The MEDICINAL LEECH (Hirudo medicinalis), is a worm-shaped animal of olive-black colour, with six yellowish lines on the upper part of the body, and spotted with yellow beneath.
When fully extended, the leech is generally two or three inches in length. It is found in stagnant and muddy waters.
The use of leeches in medicine is to diminish the accumulation of blood in any particular part of the body. This they do by fixing themselves to the spot, forming a hole with three sharp teeth which are situated triangularly in their mouth, and sucking the blood through the wound. When they have drawn sufficient, they are easily loosened by putting upon them a small quantity of salt, pepper, or vinegar.
Leeches are caught in various ways, but one of the best is to throw bundles of weeds into the water which they inhabit. These, if taken out a few hours afterwards, will generally be found to contain a considerable number. They are collected from several of the rivers in the south of England, and are kept for sale sometimes, many thousands together, in casks or tubs of spring water. This is frequently changed, and all the slime and filth which exude from their bodies is carefully washed away.
It is said that if leeches be kept in glass vessels they will indicate a change of weather, by becoming at such times peculiarly restless and active.
271. The OFFICINAL CUTTLE-FISH (Sepia officinalis), is a marine animal, with somewhat oval body nearly surrounded by a margin, eight short and pointed arms, and two tentacula four times as long as the arms, all furnished with numerous small cup-shaped suckers.
These animals are found in considerable numbers in the European seas.
By the ancients, cuttle-fish were in great esteem as a delicacy for the table; and, even at the present day, they are frequently eaten by the Italians, and by the inhabitants of other countries on the shores of the Mediterranean.