GALL, in the animal economy, the same thing as bile. (See ANATOMY.) It was customary among the Jews to give gall or a bitter potion to persons suffering death under the sentence of the law, for the purpose of rendering them less sensible to pain. At our Saviour's crucifixion, according to St Matthew, "They gave him vinegar to drink, mingled with gall"—ἔξος μετὰ χολῆς; whereas in St Mark it is said to be "wine mingled with myrrh"—a very bitter ingredient. It would hence appear that the word χολή was used figuratively, or generally for whatever is exceedingly bitter.
The clarified gall of the ox is employed in the arts for several purposes. It is used by the scourers of clothes to remove spots of grease; and by painters in water-colours.
GALL or GALL-NUT (Lat. galla). Gall-nuts are excrescences which are formed on the Quercus infectoria, a species of oak that abounds in Asia Minor, Syria, Persia, &c., and on some others. They are produced by the attacks of the cynips, a small insect which deposits its eggs in the tender shoots of the tree; and when the maggot is hatched, it occasions a morbid excrescence of the surrounding parts. Galls are inodorous, and have a nauseously bitter and astringent taste. They are nearly spherical, and vary in magnitude from the size of a pea to that of a hazel-nut. When good, they are of a black or deep olive colour, and the surface is tubercular. In commerce they are distinguished into white, green, and blue galls. The two latter kinds are the best. The chief products of galls are tannin and gallic acid. Galls are very extensively used in dyeing, and in the manufacture of ink. (See DYEING.) They are the most powerful of all the vegetable astringents, and are frequently used in medicine. Galls are chiefly imported from Aleppo, Tripoli, Smyrna, and Said. It is not unusual to dye the white or inferior kind blue, in order to increase their value; but this fraud is easily detected by their being perforated, and lighter than the genuine blue galls. (McCulloch's Dict. of Com.) The term gall is also applied generally to any protuberance or tumour produced on trees by the puncture of insects.