360 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



Guaiacum are filled with resin. Calcium oxalate is secreted in leaves 

 in the form of rosette aggregates and in the axis in solitary crystals. 



Guiaci Lingnum. LIGNUM GUAIACI, LIGNUM VIT^B, LIGNUM 

 SANCTUM, LIGNUM BENEDICTUM OR GUIAC WOOD. The wood of 

 Guaiacum officinale and G. sanctum (Fam. Zygophyllaceae), small 

 evergreen trees of tropical America. Either the heart wood is used, 

 or the wood from the younger twigs and stems freed from the bark 

 is employed. 



Description. Heartwood in billets from 10 to 30 cm. in length, 

 dark brown, becoming on exposure greenish-brown; wood of twigs 

 and stems in pieces from 2 to 3 cm. in thickness, light yellow, becom- 

 ing on exposure greenish-brown; very heavy, hard; fracture tough, 

 splintery; inner .transverse surface showing irregular concentric 

 layers of alternating dark and yellow zones, tracheae large, dark 

 brown, medullary rays narrow and yellow. 



Inner Structure. Trachess comparatively few with large lumina, 

 rather short, having thick walls and containing a light yellowish or 

 dark brownish-red resin; wood parenchyma having monoclinic 

 prisms of calcium oxalate; wood fibers numerous with very thick 

 walls, of an irregular contour, and containing a yellowish-red or 

 brownish-red resin; medullary rays mostly 1 cell wide, occasionally 

 3 to 6 cells wide, and arranged in 4 longitudinal rows. 



Constituents. About 15 per cent of resin, the constituents of 

 which are given under Guaiac resin. Also, 1 per cent of volatile 

 oil, vanillin, saponinic acid and saponin. The latter principle occurs 

 in large amounts in the bark and in least quantity in the heartwood. 

 The activity of the drug is supposed to be due to its saponin and not 

 its resin and we would naturally expect the bark to be used in medi- 

 cine rather than the wood or its resin. The latter, however, is official 

 in a number of Pharmacopoeias. 



GUAIACUM. Guaiac Resin. A resin obtained from the stem 

 and branches of Guaiacum officinale, a small tree growing in 

 Florida, the Antilles and northern South America, and Guiacum 

 sanctum (Fam. Zygophyllacese) indigenous to the West Indies and 

 the northern part of South America. The resin exudes sponta- 

 neously or is obtained from incisions in the bark or by heating the 

 fallen trunks. The commercial article comes chiefly from Cuba and 

 Hayti. The resin obtained from trees growing in the Bahama 

 Islands is most highly esteemed. 



Description. Usually in irregular masses; externally greenish- 

 brown, frequently covered with a greenish powder; brittle, the frac- 

 ture having a glassy luster and being yellowish-green or reddish- 



