This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Thus Pharm. Lond. Frankincense: a solid brittle resin, brought to us in little glebes or masses, of a brownish or yellowish colour on the outside, internally whitish or variegated with whitish. specks. It is supposed to be the produce of the pine that yields the common turpentine, and to concrete upon the surface of the terebinthinate juice soon after it has issued from the tree.
This resin has a bitterish acrid unpleasant taste, and no considerable smell: it dissolves totally in rectified spirit, but is scarcely acted upon by watery menstrua. It may be looked upon as a mild corroborant; though at present it is little otherwise made use of than as an ingredient in theriaca, and externally in plasters. An officinal plaster, made with half a pound of frankincense and three ounces of dragons blood in powder stirred into two pounds of the common plaster melted, now takes its name which was formerly roborans, from this ingredient.