Frankincense, a designation of resinous substances which when burned give out an agreeable odor, and are used in the ceremonies of the Roman Catholic church. The common frankincense of commerce, also called gum thus, is an exudation of the Norway spruce (abies excelsa). The turpentine from our southern pine forests, also called white turpentine, when old and hard, is often sold as a substitute for the European.-The true frankineense of the ancients is the fragrant gum resin known in medicine as olibanum, the product of the tree Boswellia serrata, which grows among the mountains of central India and upon the Coromandel coast. It is imported from Calcutta in the form of roundish lumps or tears, which have a pale yellow color, are somewhat translucent, and are covered with a whitish powder produced by friction. It has an agreeable balsamic odor, but its taste is acid and bitter; it softens when chewed, adheres to the teeth, and whitens the saliva. It readily inflames, and imparts in burning a fragrant odor. This is the property which rendered it so highly esteemed with the ancients, by whom it was introduced as one of the ingredients in their incense, which was burned (incensum), according to Maimonides, to conceal the smell arising from the slaughtered animals of the sacrifices.
According to others, the smoke of its burning was regarded as in itself an acceptable offering, because it was symbolical of prayer and of interior worship. Olibanum is but imperfectly soluble in water. Alcohol takes up about three fourths of it, forming a transparent solution. Braconnot obtained 8 parts of volatile oil, 56 of resin, 30 of gum, and 5.2 of insoluble glutinous matter; loss 0.8. The article finds but little use in medicine except for fumigations, and rarely as an ingredient of plasters.-Another variety of frankincense, the source of which is not well ascertained, is brought from Arabia.
Olibanum (Boswellia serrata).