The Lignum Vitæ of Jamaica (G. officinale) and that of the Bahamas (G. sanctum), of which authentic specimens have been kindly placed at our disposal by Mr. G. Shadbolt, display the same appearance as well as microscopic structure.[410]
Microscopic Structure—The wood consists for the most part of pointed, not very long, ligneous cells (libriform), traversed by one-celled rows of medullary rays. There are also thin layers of parenchymatous tissue, to which the zones apparent in a transverse section of the drug are due. The pitted vessels are comparatively large but not very numerous. The structure of the sapwood is the same as that of the heartwood, but in the latter the ligneous cells are filled with resin. The parenchymatous cells contain crystals of oxalate of calcium.
Chemical Composition—The only constituent of any interest is the resin which the heartwood contains to the extent of about a fourth of its weight. The sapwood afforded us 0·91 and the heartwood 0·60 per cent. of ash.
Commerce—Lignum Vitæ varies much in estimation, according to size, soundness, and the cylindrical form of the logs. The best is exported from the city of Santo Domingo, whither it is brought from the interior of the island. The quantity shipped from this port during 1871 was 1494 tons;[411] 220 tons were exported in 1877 from Puerto Plata on the northern coast of the island. The wood obtained from the Haytian ports (of the western part of the same island) is much less esteemed in the London market.
Some small wood of good quality comes from the Bahamas, and an ordinary quality, also small, from Jamaica. From the latter island, the quantity exported in 1871 was only 14 tons;[412] from the Bahamas in the same year 199 tons.[413] Lignum Vitæ was shipped from Santa Marta in 1872 to the extent of 115 tons.[414]
Hamburg is also an important place for the wood under notice; in 1877 there were imported 22,404 centners from S. Domingo and 3551 centners from Venezuela.
Uses—Guaiacum wood is only retained in the pharmacopœia as an ingredient of the Compound Decoction of Sarsaparilla. It is probably inert, at least in the manner in which it is now administered.[415]
Adulteration—In purchasing guaiacum chips it is necessary to observe that the non-resinous sapwood is absent, and still more that there is no admixture of any other wood. A spurious form of the drug seems to be by no means rare in the United States.[416]
RESINA GUAIACI.
Guaiacum Resin; F. Résine de Gaïac; G. Guaiakharz.