or Mastichi, the μαστίχη of the ancient Greeks, is a concrete resinous exudation from the trunk and branches of the Pistacia lentiscus (Nat. Ord. Anacardiaceae), a bush about 12 feet high, growing on the coasts and islands of the Mediterranean, and particularly the island of Chios, where it is very abundant, and is extensively cultivated for its resin. Mastic is produced either by spontaneous exudation or by transverse incisions made in the bark in the month of August, when the resin exudes in tears, and either hardens upon the tree or falls to the ground. In the former case it is of a superior quality, and is called picked mastic, consisting of roundish, elongated, or flattened tears, varying in size between a pepper-corn and a hazelnut, of a pale yellow colour, and translucent, brittle, and glassy in fracture, and possessing a slight but agreeable balsamic odour and taste. This kind of mastic is sometimes adulterated with sandarach. The coarser kind, called mastic in sorts, is of a greyish-brown or black colour, and is rendered impure by the presence of fragments of wood, bark, and sand, collected by the resin in falling to the ground.

Mastic, besides containing traces of volatile oil, produces by dissolution in boiling rectified spirit a white ductile substance, which some have regarded as a peculiar principle under the name of Masticin. Mastic is much used by the Turkish ladies for consolidating the gums, cleaning the teeth, and sweetening the breath. When chewed it becomes ductile, grey, and opaque. It is also employed occasionally for stuffing decayed teeth. It is chiefly used in