_Opopanax_ is the inspissated juice of the root of _Opoponax Chironium, Koch_, or _Ferula Opoponax, L._ It forms grains or lumps of a red-yellow or brown color, and has a fracture of a waxy lustre. It can be rubbed to a gold-yellow powder. It has a strong and peculiar odor, and a very bitter and balsamic taste. With water it forms an emulsion, while it is only partially soluble in spirit of wine. It contains very little volatile oil, and a resin which melts at 212° F., and is soluble in ether and aqueous alkalies. It further contains gum, organic and inorganic salts, and foreign admixtures. Opopanax is but little used in perfumery. For _Extraits_ the opopanax oil is better adapted than the tincture prepared from the gum, the latter coloring the _Extrait_ dark. _Olibanum or Frankincense_ is the inspissated juice of various varieties of _Boswellia_, partially indigenous to Africa and partially to Asia. The pure pieces are pale yellow, seldom reddish, transparent, or opaque, brittle, covered with a mealy coating and of a splintery fracture. The specific gravity of olibanum is 1.22; its odor is slightly balsamic, and its taste bitter and pungent. It melts only incompletely when exposed to heat, diffusing an agreeable odor. It consists in 100 parts of 5 to 7 parts of a clear volatile oil, boiling at 323.6° F., and of specific gravity 0.86, 56 parts of acid resin, and 30 to 36 parts gum, which corresponds with gum-arabic. With water it forms a milky fluid, and is mostly dissolved by spirit of wine. Selected olibanum (_Olibanum electum_) is the best commercial variety, while _Olibanum naturale_, _O. in lacrymis_, and _O. in sortis_, form darker pieces intermingled with separate paler grains, and contaminated by pieces of bark, and wood and sand. Olibanum is only adulterated with sandarac and naturally exuded pine resin, inspissated to tears by exposure to the air. The former is recognized by the fracture being glassy and transparent, and the latter by completely dissolving to a clear solution in spirit of wine. Olibanum serves as an addition to fumigating pastilles, etc. _Sandarac_ is the resin exuding from the bark of _Thuja articulata, Desf._, or _Callitris quadrivalvis, Vent._, which grows in Barbary. It forms pale yellow, transparent, brittle grains with a glassy fracture, which have a specific gravity of 1.06 to 1.09 and fuse readily. Its odor is slightly balsamic and its taste somewhat bitter. Sandarac softens at 212° F. and melts at 275° F. It dissolves in hot absolute alcohol, ether, and amyl alcohol, is less soluble in chloroform, petroleum-ether, and volatile oils, and insoluble in benzol. In 90 per cent. alcohol ⅘ of it dissolve; the term _sandaracin_ has been applied to the insoluble portion. According to Unverdorben, sandarac consists of three different resins. It is sometimes employed in fumigating pastilles. CHAPTER VI. PERFUME-SUBSTANCES FROM THE ANIMAL KINGDOM.