Officinal. Quercus, Lond. Quercus Roboris cortex, Edin.

Dub. Oak bark.

Syn, Ecorce de la Chene commune (F.), Eichenrinde (G.), Cortcccia della Quercia (I.).

1 Phil. Mag. vol. ix. p. 401. 2 Ann. de Chim. et Phys. ix. p. 187.

2 Misy quoque et Galla, si puribus portionibus misceantur, corpus consumunt. Celsus. 1. v. c. xxii.

Graaeorum, Eiche (G.), Eik (Dutch;, Eeg (Dan.), Ek (Swed.), Da-rach (Galic), Le Chene (F.), Quercia (I.), Roble.(S. Port.), Dub (Russ.), Mesche (Turk.), Baalut (Arab.), Tamtna (Finnl.), Pelut (Pers.),

This species of oak is indigenous; but it is found also all over Europe, in the north of Asia, and the northern extremity of Africa. It is a well-known beautiful tree, often rising to the height of 90 or 100 feet, and attaining a great degree of thickness in the trunk, which is covered with a rough, brown bark. The leaves are alternate, supported on short petioles, ovate-oblong, deeply sinuated, forming obtuse lobes; deep green, smooth, and shining on the upper surface; paler, and nearly glaucous underneath. The flowers are in axillary catkins: the male lax, pendulous, many-flowered, and yellow; the female longer, peduncled, and only three-flowered. The calyx of the male flower is membranous, bell-shaped, often five-cleft; while that of the female is coriaceous, scaly, downy, and becoming hemispherical, entire, and woody. The stamens are ten, longer than the calyx. The germen is ovate, crowned with a short cylindrical style and three stigmas. The fruit is an elliptical, coriaceous, smooth nut, fixed in the calyx as in a shallow cup, but at length dropping from it. The peduncles of the fruit, which are from two to three inches long, distinguish it from the Q. robur, the fruit of which is sessile.

It ripens its acorns in October.

Almost every part of the oak is astringent, but the bark only is officinal; and, as its epidermis is perfectly inert, it is taken for medicinal purposes from the smaller branches, the epidermis of which is still thin, and scarcely cracked. The bark cut in spring is preferable to that which is cut in winter, as it contains four times the quantity of the astringent principle or tannin.1

Qualities. - Oak bark is inodorous, has a rough astringent taste, and yields its virtues to both alcohol and water. The watery effusion is affected by all those tests which indicate the presence of gallic acid, tannin, and extractive (see Decoctum Quercus). Sir H. Davy2 found that j. of the inner cortical part of young oak bark affords, by lixiviation, 111 grains of solid matter, of which 77 are tannin; the cellular integument, or middle-coloured part, yields grs. 43 only of solid matter, of which 19 are tannin; and the epidermis furnished scarcely any quantity either of tannin or of extractive. The quantity of tannin, however, varies according to the size and age of the trees, and the season at which they are barked. Vau-quelin discovered that the infusion of oak bark does not precipitate tartarized antimony, nor the infusion of Santa Fe cinchona, which resembles the officinal red cinchona, although both of these are precipitated by infusion of galls.

1 Biggin. Phil. Trans, 1799. 2Phil Trans. 1803. .

I find, however, that infusion of oak bark forms a precipitate with infusion of yellow cinchona bark; and with solutions of the salts of quina and cinchonia.

Medical properties and uses.-Oak bark is tonic and astringent. It has been given, united with bitters and aromatics, with seeming advantage, in intermittents; but it is in every respect inferior to cinchona, and cannot be depended on. It is, however, useful in obstinate diarrhoea and alvine haemorrhages; and it is strongly recommended in the malignant coryza (snuffles) of infants, when, in spite of keeping the bowels regular, and the use of cordials, the child becomes weak and pallid.1 Its principal use is as a local astringent. (See Decoctum Quercus.)

The dose in substance may be from grs. xv. to grs. xxx.: but it is so difficult to pulverize, that it is seldom given in this form.

Officinal preparations. - Decoctum Quercus, L. Extractum Quercus, D.