Spec. Plant. Willd. iv. 423. Cl.21. Ord.6. Monoecia Polyandria. Nat. ord. Cupuliferae. G. 1692. Male. Calyx commonly five-cleft. Corolla none.

Stamens five to ten. Female. Calyx one-leafed, entire, rough. Corolla none.

Styles two to five. Nut coriaceous, surrounded at the base by the persistent calyx. * * With toothed leaves. Species 33. Q. infectoria. Dyer's Oak. Olivier's Travels (translation), i. 41. t. 14, 15. Med. Bot. v. p. 4. t. 2. ***** With sinuated leaves and beardless lobes. Species 65. Q. pedunculata. Common White Oak. Med. Sot.

3d edit. 23. t. 10. Michaux, North American Sylva, vol. i. pl. 2,

(Q. Robur.) Smith, Flora Brit. 1026. Michaux, b. c.

1. Quercus infectoria. (Quercus Cerris, Edin.) Officinal. Gallae, Lond. Edin. Gallae, Dub. The Gall.

Syn. Noix de Galles(F.), Gallapfel ( G.), Galnoot (Dutch), Galdaebel (Dan.), Gallaple (Swed.), Galle (I.), Agalle de Levante (S.), Galha (Port.), Maju P'hal (H. & San.), Machakai ( Tarn.), Afis (Arab.), Mazu (Pers.), Maphul (Duk.).

The Dublin College has not named any particular species of oak as furnishing the gall; the Edinburgh College has particularized the cerris : but the London has correctly stated it to be Q. infectoria. It is well known that most of the other species of Quercus produce galls, yet the species from which the galls of commerce are obtained has been distinctly pointed out by Olivier from his personal knowledge; the species above named is the real tree; and, as we know no reason for doubting his veracity, we shall copy his description of it.

The quercus infectoria is scattered throughout all Asia Minor, from the Bosphorus as far as Syria, and from the coasts of the Archipelago as far as the frontiers of Persia. It has a crooked stem, seldom exceeds six feet in height, and more frequently assumes the character of a shrub than that of a tree. The leaves, which are deciduous in autumn, are on short petioles, smooth, of a bright green colour on both sides, and obtusely toothed: the acorn is elongated, smooth, two or three times longer than the cup, which is sessile, in a slight degree downy and scaly: the gall comes at the shoots of the young boughs, and acquires from four to twelve lines in diameter; the insect which produces it is the cynips quercusfolii of Linnaeus (diplolepsis gallae tinctoriae of Geoffrey), a small hymenopterous insect or fly, with a fawn-coloured body, dark antennae, and the upper part of the abdomen of a shining brown. The insect punctures the tender shoot with its sting, which is spiral, and deposits its egg in the puncture.

This occasions a morbid irritation in the vessels of the part; the gall rises in a few hours, and attains its full size in a day or two, before the larva is hatched : the egg grows with the gall: and it is by the irritation which it keeps up,-not, as has been supposed, by the maggot feeding on the juices of the plant, -that the morbid excitement is maintained in the vessels of the part, sufficient for the production of this kind of vegetable wen.

Galls are gathered before the larva within them changes to a fly, and eats its way out; for, when this has happened, the galls become lighter, and contain less of the astringent principle. The first galls that are picked are named yerli by the natives, and are known in trade by the terms black or blue galls, and green galls. Those which are gathered afterwards, from the circumstance of their being pierced, are of an inferior quality, and are denominated white galls. The best galls are those of Aleppo, Smyrna, Magnesia, Karahisser, Diar-bekir, and the interior of Natolia. Those which are brought to this country come chiefly from Aleppo, in bags and cases.

Qualities.-Galls are inodorous, and have a bitter, very astringent taste. They are nearly round, of different magnitudes, from the size of a pea to that of a hazel nut; smooth on the surface, yet studded with tuberosities; and, when good, of a blackish blue or deep olive colour: a white or a red hue indicates an inferior quality.1 They are heavy, brittle, break with a flinty fracture, and display a compact, striated texture. The whole of their soluble matter is taken up by about forty times their weight of boiling water, and what remains is tasteless. The decoction, on cooling, deposits a pale yellow precipitate, which is a tannate of starch. Alcohol, digested on powdered galls, takes up seven parts in ten, and ether five parts. The watery infusion reddens tincture of litmus, and forms precipitates with solution of isinglass, the infusions of cinchona bark, opium, cusparia bark, and columba root; but not with infusion of quassia, nor of saffron. Sulphuric acid throws down a yellowish, curdy; hydrochloric acid, a flaky, whitish precipitate; while nitric acid changes the colour only of the infusion, first to a deep orange, and afterwards to a paler orange yellow. The solution of ammonia occasions no precipitate, but deepens the colour: the carbonate, however, produces a precipitate.

Carbonate of potassa throws down a yellowish, flaky precipitate, and extricates ammonia; and lime-water a copious deep green precipitate. Precipitates also are formed with solutions of quina, cinchonia, the salts of morphia, emetina, and of the following metallic salts: acetate and diacetate of lead, greyish; tartarized antimony, yellowish; sulphate of copper, brown; sulphate of iron, bluish-black; sulphate of zinc, reddish-black, but very slowly formed; nitrate of silver, deep olive; and nitrate of mercury, bright yellow. The bichloride of mercury renders the infusion milky and opaque, but no precipitate is formed. The alcoholic tincture reddens litmus, and is affected by the same re-agents as the watery infusion. The ethereal tincture, when evaporated on water, leaves on the side of the glass an opaque pellicle, and on the surface of the water small drops of an oily, resinous-like matter, while the substratum of water becomes charged with tannin and gallic acid. The pellicle and resinous-like matter is plastic, tenacious, resembling birdlime treated with ether; and when subjected to heat, melts, swells, burns, and leaves a dense black charcoal.

These experiments show results which cannot altogether depend on the presence of tannin, gallic acid, extractive, or mucilage, which are supposed to be the constituents of galls. In Sir H. Davy's experiments 500 grains of Aleppo galls yielded to pure water, by lixiviation, 185 grains of solid matter; of which 130 were tannin, 31 gallic acid and extractive, 12 mucilage and matter rendered insoluble by the evaporation, and 12 saline and earthy matter. From different experiments, the proportion of extractive, however, if any, is very small: none appears in the evaporation of the ethereal tincture; and Dr. Bostock's experiments render the existence of mucilage very doubtful. From the experiments of Professor Branchi, it appears that galls also yield, by distillation with water, a concrete, volatile oil1: and M. Braconnot has discovered in them a new acid, which he has rather affectedly termed ellagic, from the word galle reversed ! 2 It is an insipid, inodorous, white powder, with a slight tinge of red, and insoluble in boiling water. When mixed with nitric acid, and very gently heated, the mixture acquires a reddish tint, gradually passing to a deep-blood red. Hence we may conclude, that the constituents of galls, besides tannin and gallic acid, are the above oil and ellagic acid.

When powdered galls in a long filter are acted on by unrectified ether, and the percolated fluid evaporated and reacted upon by alcohol, pure tannin is obtained.

1 This is the character of the galls from which the insect has escaped, and which are also of a brighter colour. Another species of gall, produced by another species of the insect, is,also, Olivier says, found on the same oak. It is spongy, very light, of a brown red colour, covered with a resinous coat, and furnished with a circular row of tubercles placed nearly towards the most protuberant part. Their astringency is very inferior, and they are used only to adulterate the better sort.

Medical properties and uses,-Galls are the most powerful of the vegetable astringents. They are seldom used as an internal remedy, although, in combination with bitters or aromatics, they have been given in obstinate diarrhoeas, passive intestinal haemorrhages and intermittents. They are frequently ordered in the form of gargles and injections; and an ointment formed of galls in fine powder, with eight parts of simple ointment and a small proportion of powdex*ed opium, is a useful application to blind piles. A strong decoction applied to warts on the penis destroys them : this use of galls was proposed by M. Alcock.3 For internal exhibition, the dose of galls is from grs. x. to Эj., which may be given twice or thrice a day.

Officinal preparations.-Tinctura Gallarum, E. D. Unguentum Gallae comp., L. E. D.