PITCH, TAR, TUEPENTIKE, ETC. 191 



prepared resinous exudation of Abies Canadensis, 

 the hemlock spruce of the United States and Canada ; 

 natural order Coniferse. 



These two varieties are used chiefly in making 

 plasters. 



3. Fix Liquida, tar, an empyreumatic oleoresin, 

 obtained by the destructive distillation of the wood of 

 Pinus pallustris and other species of Pinus, natural 

 order Coniferse. A thick, viscid, semi-fluid, of a 

 brownish-black color, heavier than water, transparent 

 in thin layers, becoming granular and opaque by age ; 

 having an acid reaction, an empyreumatic, terebin- 

 thinate odor, and a sharp, empyreumatic taste. 

 Slightly soluble in water, soluble in alcohol, fixed or 

 volatile oils, and in solution of potassa or of soda. It 

 consists of pyroligneous acid, methyl alcohol, acetic 

 acid, creosote, toluine, xylene, and other hydrocar- 

 bons ; also oily bodies, especially the oil of tar and 

 pyrocatechin, a crystalline principle, which gives it 

 its granular appearance. Dose: H., Iss.-ij.; D., 

 gr. x.-xx. 



Preparations of Tar. — Oleum Picis Liquidoe, 

 oil of tar. A volatile oil distilled from tar, and con- 

 taining a great variety of compounds, including hy- 

 drocarbons, phenols, paraffin, etc., among the phenols 

 being creosote and carbolic acid. Dose: H., fl. 3 ss. 

 -iv. ; D., Tllij.-x. 



Unguentum Picis Liquidce, tar ointment, contain- 

 ing fifty per cent, of tar. 



Physiological Action op the Turpentines. 

 — They are topical irritants, general stimulants, anti- 



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