BIRTHWORT: A genus of the hexandria order, belonging to the gynandrae class of plants; and in the natural method ranking under the 11th order, Sarmentaceae. It has no calyx; the corolla consists of one entire petal; and the capsule, which is below the flower, has six cells. The species are 21; but only the five following merit description. 1. The rotunda, is a native of the south of France, of Spain, and Italy, from whence the roots are brought for medicinal use. The roots are roundish, grow to the size of small turnips, being in shape and colour like the roots of cyclamens, which are frequently sold instead of them. This sort hath three or four weak trailing branches, which lie on the ground when they are not supported, and extend two feet in length; the leaves are heart-shaped and rounded at their extremity; the flowers flowers come out singly at every leaf, toward the upper part of the stalk. They are of a purplish black colour; and are frequently succeeded by oval seed-vessels having six cells full of flat seeds. 2. The longa, is a native of the same countries. This species hath long tap-roots like carrots; the branches are weak and trailing, extending little more than a foot; the flowers come out from the wings of the leaves like the other, are of a pale purple colour, and are frequently succeeded by seed vessels like the other. 3. The serpentina, is a native of Virginia and Carolina, from whence the radix serpentina, or snake-root, so much used in medicine, is brought over. The plant rises out of the ground in one, two, and sometimes three pliant stalks, which at every little distance are crooked or undulated. The leaves stand alternately, and are about three inches long, in form somewhat like the smilax alpina. The leaves grow close to the ground on footstalks an inch long, of a singular shape, and of a dark purple colour. A round canulated capitule succeeds the flower. It is filled with seeds, which are ripe in May. The usual price of the root when dried is 6d. per pound, both in Virginia and Carolina, which is money hardly earned; yet the negro slaves employ great part of the time allowed them by their masters in search of it, which is the reason that there are seldom found any but very small plants of this species. When they are planted in gardens in those countries where they are natives, the plants increase so much in two years time, that the hand can scarce grasp the stalks of a single one. This species delights in woods, and is usually found near the roots of great trees. 4. The indica, or contrayerva of Jamaica, is a native of that island, where its roots are used instead of the true contrayerva. It hath long trailing branches, which climb upon the neighboring plants, and sometimes rise to a considerable height. The flowers are produced in small clusters towards the upper part of the stalks, which are of a dark purple colour. 5. The clematis, with heart-shaped leaves, an upright stem, with the flowers crowded in the axillae. The root is long and slender.

Culture. The first, second, and third sorts are propagated from seeds, which should be sown in the autumn, in pots filled with light fresh earth, and placed under a frame to preserve them from the frost. If they are plunged into a gentle hot-bed in the month of March, the plants will come up sooner. In summer, and in autumn when the stalks begin to decay, they must be watered. In winter they must be again sheltered; and in March before the roots begin to shoot, they must be transplanted into small separate pots filled with light earth, when they may be removed into the open air, and treated as before. The next spring they may be planted in the open air in a warm border; where, in the autumn, when their stalks decay, if the border is covered with old tanner's bark to keep out the frost, the roots will be secured; but where this care is not taken, they will frequently be killed by the frost. The fourth is tender; and therefore must be kept in a stove during the winter, or it will not live in England.

Medicinal uses. The roots of the long and round sorts, on being first chewed, scarce discover any taste, but in a little time prove nauseously bitterish; the long somewhat the least so. The root of the clematis is long and slender, rarely exceeding the thickness of a goose-quill: it instantly fills the mouth with an aromatic bitterness, which is not ungrateful. Their medical virtues are, to heat, stimulate, attenuate viscid phlegm, and promote the fluid secretions in general: they are principally celebrated in suppressions of female evacuations. The dose in substance is from a scruple to two drams. The long sort is recommended externally for cleansing and drying wounds and ulcers, and in cutaneous diseases.

The root of the serpentina is small, light, bushy, and consists of a number of strings or fibres, matted together, issuing from one common head; of a brownish colour on the outside, and paler or yellowish within. It has an aromatic smell, like that of valerian, but more agreeable; and a warm, bitterish, pungent taste. This root is a warm diaphoretic and diuretic; it has been greatly celebrated as an alexipharmacum, and esteemed one of the principal remedies in malignant fevers and epidemic diseases. In these intentions, it is given in substance from 10 to 30 grains; and in infusion, to a dram or two. Both watery and spirituous menstrua extract its virtue by infusion, and elevate some share of its flavour in distillation; along with the water a small portion of essential oil arises.

None of these articles, however, are now in so much esteem as formerly; and while all of them are banished from the Pharmacopoeia of the London college, the clematis is alone retained in that of Edinburgh.