CONIFERÆ.
TEREBINTHINA VULGARIS.
Crude or Common Turpentine; F. Térebenthine commune; G. Gemeiner Terpenthin.
Botanical Origin—The trees which yield Common Turpentine may be considered in two groups, namely, European and American.
1. European—In Finland and Russia Proper, the Scotch Pine, Pinus sivestris L.; in Austria and Corsica, P. Laricio Poiret; and in South-western France, P. Pinaster Solander (P. maritima Poiret), extensively cultivated as the Pin maritime, yield turpentine in their respective countries.
2. American—In the United States, the conifers most important for terebinthinous products are the Swamp Pine, Pinus australis Michaux (P. palustris Mill.), and the Loblolly Pine, P. Tæda L.
History—The resin of pines and firs was well known to the ancients, who obtained it in much the same manner as that practised at the present day. The turpentine used in this country has for many years past been derived from North America. Up to the last century, both it and the substance called Common Frankincense were imported from France. The late civil war in the United States and the blockade of the Southern ports, occasioned a great scarcity of American turpentine; and terebinthinous substances from all other countries were poured into the London market. The actual supplies, however, were mainly furnished by France.
Kopp[2271] quotes a passage showing that the essential oil of turpentine was known to Marcus Græcus, who termed it Aqua ardens. This almost unknown personage is the reputed inventor of Greek Fire, a dreaded engine of destruction in mediæval warfare.
Secretion—The primary formation of resin-ducts in the bark of coniferous trees has been explained by Dippel,[2272] Müller,[2273] and Frank.[2274] The subsequent diffusion of the resinous juice through the heartwood, sapwood, and bark, has been elaborately investigated by Hugo von Mohl.[2275] From the various forms under which this diffusion exists in the different species have arisen the diverse methods of obtaining the terebinthinous resins.
Thus in the wood of the Silver Fir (Pinua Picea L.) resin-ducts are altogether wanting;—and led by experience, the Alpine peasant collects the turpentine of this tree by simply puncturing the little cavities which form under its bark. In the Scotch Pine (P. silvestris L.), they are more abundant in the wood than in the bark, a fact which might be anticipated by observing how rarely this tree exudes resin spontaneously.