Definition. - A product obtained by the destructive distillation of the wood of Pinus palustris Miller, and other species of Pinus.

Description and Properties. - Thick, viscid, semifluid, blackish-brown, heavier than water, transparent in thin layers, becoming granular and opaque with age; odor empyreumatic, terebinthinate; taste sharp, empyreumatic. Tar is slightly soluble in water; soluble in alcohol, fixed and volatile oils, and solution of potassium or sodium hydrate.

The drug contains many substances, chief among which are empyreumatic volatile oil, pyrocatechin, acetone, xylol, toluol, cresols (creasote), guaiacol, phenol, etc.

Dose. - 15-60 grains (1.0-4.0 Gm.) [7 1/2 grains (0.5 Gm.), U. S. P.].

Official Preparations

Syrupus Picis Liquidae - Syrupi Picis Liquidae - Syrup of Tar (0.5 per cent.). - Dose, 1-4 fluidrams (4.0-15.0 Cc.) [1 dram (4 Cc), U. S. P.].

Unguentum Picis Liquidae - Unguenti Picis Liquidae - Tar Ointment (50 per cent.). - Used externally.

Oleum Picis Liquidae - Olei Picis Liquidae - Oil of Tar (U. S. P.). - Origin. - A volatile oil distilled from tar.

Description and Properties. - An almost odorless liquid when freshly distilled, but soon acquiring a dark reddish-brown color, and having a strong tarry odor and taste. It is readily soluble in alcohol.

Dose. - 1-5 minims (0.065-0.3 Cc.) [3 minims (0.2 Cc), U. S. P.].