Dock: a perennial plant bearing numerous imperfect flowers set in double cups: the outermor!: cup consists of three small green leaves; the inner of three larger reddish ones, which become a covering to a glossy triangular seed.

I. Oxylapathum. Lapathum acutum folio piano C. B. Rumex acutus Linn. Sharp-pointed wild dock: with long acuminated leaves, not curled about the edges, growing gradually narrower from the bottom to the point; and the seed-covers indented and marked with little tubercles. The roots are of a brownish colour on the outside, and of a yellowish within, which grows deeper in drying.

The roots of the sharp-pointed dock have a bitterish astringent taste; and no remarkable smell: the roots of the other common wild docks are nearly of the same quality, equally discover their astringent matter both to the taste and by striking an inky blackness with solution of chalybeate vitriol, and have been often sub-stituted in our markets to those of the sharp-pointed kind; which last are generally, and, so far as can be judged from their taste, justly, accounted the most efficacious. They are sup-posed to have an aperient and laxative, as well as an astringent and corroborating virtue; approaching in this respect to rhubarb, but differing widely in degree, their stypticity being greater, and their purgative quality, if really they have any purgative quality at all, far less. They stand recommended in habitual costive-nefs, obstructions of the viscera, scorbutic and cutaneous maladies: in which last intention, fomentations, cataplasms, or unguents of the roots, have been commonly joined to their internal use: in many cases, the external application alone is said to be sufficient. Their active matter is taken up both by water and rectified spirit, and, on inspissating the tinctures, remains in the extracts; both the watery and spirituous extracts are considerably bitter and very austere. A decoction of half an ounce or an ounce of the fresh roots, or of a dram or twof of the dry roots, is commonly directed for a dose.

2. Hydrolapathum five Herba britannica Pharm. Edinb. Lapathum aquaticum folio cubi-tali C. B. Rumex aquaticus Linn. Great wild water-dock: with very large leaves, two or three feet longs the seed-covers not indented. The roots are externally blackish, internally white with a faint reddish tinge, which, in drying, changes in some parts to a yellowish: the internal part of the fresh root, exposed to the air, or of the dry root moistened, soon changes supersicially to a deep yellow or brown.

The roots of the water-dock strike a black colour with solution of chalybeate vitriol, like those of the preceding species, but have a much stronger and more acerb taste; which is dissused equally, so far as can be judged, through the whole substance of the root. They give out their active matter both to water and rectified spirit, and tinge both menstrua of a pale yellowifh or reddish brown colour, though in chewing they render the saliva only milky.

The herba britannica of the ancients, celebrated as an antiscorbutic, and of which the knowledge was long loft, was proved by Mun-tingius, towards the end of last century, to be no other than this great water-dock. Mun-tingius endeavours to prove also, that its name britannica was not derived from that of our island, but from Teutonic words expressing its power of fastening loose teeth, or of curing the disease which makes them loose. Later experience has shewn, that it is a medicine of very considerable efficacy, both externally in lotions against putrid spungy gums and ulcerations, and as an internal antiscorbutic: Boer-haave assures us, that in these cases he has known many instances of its happy effects. It is supposed to be of service also in cutaneous desedations different from the true scurvy, in rheumatic pains, and in chronical disorders proceeding from obstructions of the viscera. It has been chiefly used in medicated wines and small ales, with the addition generally of fome spicy materials, and sometimes of other antiscorbutic plants, as scurvygrass, buckbean, horfe-radish, etc.

3. Rhabarbarum monachorum Pharm. Paris. Lapathum hortense latisolium C. B. Hippolapathum; Patientia. Rumex Patientia Linn. Monks rhubarb, garden patience: with large, broad, acuminated leaves; reddish, branched stalks; the leaves that cover the seeds unindented, and a tubercle on one of them: the root is of a yellow colour, with red veins, approaching in appearance to rhubarb.

This root is supposed to possess the virtues of rhubarb, in an inseriour degree. It is ob-viously more astringent than rhubarb: but comes very far short of it in purgative virtue, though given, as usually directed, in double its dole; nauseating the stomach, without producing any considerable evacuation. It com-municates a deep yellow tincture both to water and spirit.