2. Brazilian Elemi—Was described as long ago as 1658 by the traveller Piso, as a substance completely resembling the elemi of the Old World and applicable to the same purposes. It is the produce of several trees described as species of Icica, as I. Icicariba DC.,[618] I. heterophylla DC., I. heptaphylla Aublet, I. guianensis Aubl., I. altissima Aubl.—In New Granada a similar exudation[619] is furnished by I. Caranna H.B.K.
A specimen in our possession from Pernambuco[620] is a translucent, greenish yellow, fragrant, terebinthinous resin, which by cold spirit of wine may be separated into two portions, the one soluble, the other a mass of colourless acicular crystals. The resin spontaneously exuded and collected from the trunks, is often opaque and white, grey, or yellowish, looking not unlike fragments of old mortar. The microscope shows it to be made up of minute acicular crystals.[621]
3. Mauritius Elemi—Fine specimens of this substance and of Colophonia Mauritiana DC. the tree affording it, were sent to one of us (H.) in 1855 by Mr. Emile Fleurot of Mauritius. The resin accords in its general characters with Manila elemi, like which it leaves after treatment with cold spirit of wine, an abundance of crystals resembling amyrin.
4. Luban Meyeti[622] or Luban Mati.—This substance, which we claim to be the Oriental or African Elemi of the older writers, and also one of the resins anciently designated Animi,[623] is the exudation of Boswellia Frereana Birdwood, a remarkable tree gregarious on the bare limestone hills near Bunder Murayah to the west of Cape Gardafui. The tree which is called Yegaar by the natives, is of small stature, and differs from the other species of Boswellia growing on the same coast in having glabrous, glaucous leaves with obtuse leaflets, crisped at the margin.[624] The bark is smooth, papery, and translucent, and easily stripped off in thin sheets which are used for writing on. Though growing wild, the trees are said by Capt. Miles[625] to be carefully watched and even sometimes propagated. The resin exudes after incision in great plenty, soon hardens, and is collected by the Somali tribes who dispose of it to traders for shipment to Jidda and ports of Yemen: occasionally a package reaches London among the shipments of olibanum. It is used in the East for chewing like mastich.
In modern times Luban Mati has been mentioned by Wellsted in his “Travels in Arabia” (1838).
Luban Meyeti occurs in the form of detached droppy tears and fragments, occasionally in stalactitic masses several ounces in weight. It breaks very easily with a brilliant conchoidal fracture, showing an internal substance of a pale amber yellow and perfectly transparent. Externally it is more or less coated with a thin opaque white crust, which seen under the microscope appears non-crystalline. Many of the tears have pieces of the thin, brown, papery bark adhering to them. The resin has an agreeable odour of lemon and turpentine, and a mild terebinthinous taste.
Treated with alcohol (·838) it is almost entirely dissolved; the very small undissolved portion is not crystalline. The former agrees with the formula C₂₀H₃₀O₂. 20 lb. of Luban Mati yielded us 10 ounces of a volatile oil (= 3·1 per cent.) having a fragrant odour suggestive of elemi and sp. gr. 0·856 at 17° C. The oil examined in a column 50 millim. long, deviates the ray 2°·5 to the left. By fractional distillation we found it to consist of dextrogyre hydrocarbon, C₁₀H₁₆, mixed with an oxygenated oil which we did not succeed in isolating; the latter is evidently lævogyre, and exists in proportion more than sufficient to overcome the weak dextrogyre power of the hydrocarbon.
There is no gum in this exudation; it is therefore essentially different from olibanum, the product of closely allied species of Boswellia.[626]