Unguentum Picis Liquidae (U. S. P.)—Tar Ointment.

Related entry: Pix Liquida (U. S. P.)—Tar

Preparation.—"Tar, five hundred grammes (500 Gm.) [1 lb. av., 1 oz., 279 grs.]; yellow wax, one hundred and twenty-five grammes (125 Gm.) [4 ozs. av., 179 grs.]; lard, three hundred and seventy-five grammes (375 Gm.) [13 ozs. av., 100 grs.]; to make one thousand grammes (1000 Gm.) [2 lbs. av., 3 ozs., 120 grs.]. Melt together the yellow wax and the lard at a moderate heat; then incorporate the tar, strain the mixture through muslin, and stir the ointment constantly until it is cool"—(U. S. P).

Action and Medical Uses.—This is a stimulating ointment. It is used principally in tinea capitis and ringworm of the scalp, being kept constantly applied to the part by means of a cap. It has also been efficient in some other cutaneous diseases, particularly the dry stage of eczema. It may be applied to unhealthy ulcers.

Related Ointments.—UNGUENTUM PICIS COMPOSITUM (N. F.), Compound tar ointment. "Oil of tar, four grammes (4 Gm.) [62 grs.]; tincture of benzoin (U. S. P.), two cubic centimeters (2 Cc.) [32♏]; oxide of zinc, three grammes (3 Gm.) [46 grs.]; yellow wax, twenty-six grammes (26 Gm.) [401 grs.]; lard, thirty-two grammes (32 Gm.) [1 oz. av., 56 grs.]; cottonseed oil, thirty-five grammes (35 Gm.) [1 oz. av., 103 grs.]. Melt the yellow wax and lard with the cotton-seed oil at a gentle heat. Add the tincture of benzoin, and continue heating until all the alcohol has evaporated. Then withdraw the heat, add the oil of tar, and finally the oxide of zinc, incorporating the latter thoroughly, so that on cooling a smooth homogeneous ointment may result"—(Nat. Form).

UNGUENTUM PICIS BETULAE, Unguentum rusci, Wolff's tar ointment.—Birch tar, 4 parts; Unguentum, 21 parts. Mix.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.