Syrupus Picis Liquidae (U. S. P.)—Syrup of Tar.
Related entry: Pix Liquida (U. S. P.)—Tar
Preparation.—"Tar, seventy-five grammes (75 Gm.) [2 ozs. av., 282 grs.]; water, one hundred and fifty cubic centimeters (150 Cc.) [5 fl℥, 35♏]; boiling distilled water, four hundred cubic centimeters (400 Cc.) [13 fl℥, 252♏]; glycerin, one hundred cubic centimeters (100 Cc.) [3 fl℥, 183♏]; sugar, eight hundred grammes (800 Gm.) [1 lb. av., 12 ozs., 96 grs.]; distilled water, a sufficient quantity to make one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]. Mix the tar intimately with about one hundred grammes (100 Gm.) [3 ozs. av., 231 grs.] of white sand, pour on the water, and stir frequently during twelve hours; then pour off the water and throw it away. Pour the boiling distilled water upon the residue, stir well and frequently during 15 minutes, add the glycerin, and set the vessel aside for 24 hours., occasionally stirring. Decant the clear solution, and filter. Dissolve the sugar in the filtrate with the aid of a gentle heat; allow the liquid to cool, then strain it, and pass enough distilled water through the strainer to make the product measure one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]; Mix thoroughly"—(U. S. P.)
The official process very properly directs the washing of the tar which removes the acetic acid and other irritant impurities, and the glycerin is intended to prevent turbidity. The official syrup should have a tarry odor, a yellowish hue, and a somewhat bitterish taste. It is of acid reaction and turns brown when treated with alkalies.
Action, Medical Uses, and Dosage.—This forms a very useful remedy in the treatment of chronic pulmonary and bronchial affections, and also acts as a diuretic in certain diseases of the bladder and kidneys. The dose is from a dessert to a tablespoonful, repeated 3 or 4 times a day.