The residue of the distillation of the turpentines from various species of Pinus and Abies.

Characters.-Translucent, yellowish, brittle, pulverisable; fracture shining; odour and taste faintly terebinthinate. It is easily fusible, and burns with a dense yellow flame and much smoke. It is soluble in its own weight of oil of turpentine.

Composition.-Resin consists of three resinous acids, abietic, sylvic, and pimaric, C20H3002; neutral resins; and a trace of oil of turpentine.

Preparations.

1. 'Emplastrum Resinae

'Emplastrum Resinae. 1 in 9 1/2.

2. Unguentum Resinae

Unguentum Resinae. "Basilicon." 1 in 3 1/2.

Resin is contained in many other plasters and ointments, and in Charta Epispastica.

Action And Uses

Resin is a mild local stimulant, either of the unbroken skin or of sores and wounds, and the Unguentum is used for this purpose. Resin is also an ingredient of many plasters, to which it gives consistence and adhesiveness.