330 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



then purple and finally deep red. The compound formed with 

 ammonia yields haematein, a dark violet, crystalline principle having 

 a green, metallic luster and which is supposed to form in the fer- 

 mented wood used by dyers. Logwood also contains volatile oil, 

 resin, tannin and calcium oxalate. 



Allied Plants. The woods of certain species of Caesalpinia also 

 contain red coloring principles and furnish the red woods of tropical 

 America. Brazil wood is obtained from C. echinata and contains 

 the principle known as brasilin, which is colorless when first extracted, 

 but assumes a red color on exposure. Sappam or false sandal wood 

 is obtained from C. Sappam of Indo-China. Red coloring principles 

 are also found in other species of Caesalpinia and in a number of other 

 genera of the Leguminosae as well. 



SANTALUM RUBRUM. Red Saunders. The heartwood of Pter- 

 ocarpus santalinus (Fam. Leguminosse, sub-fam. Papilionaceae), a 

 tree indigenous to the southern part of Indo-China, and cultivated 

 in the southern Philippines, Ceylon and southern India, the chief 

 supplies coming from Madras. 



Description. Usually in small chips or coarse powder, red or 

 brownish-red, in transverse section slightly radiate, with numerous 

 alternate lighter and darker concentric rings, medullary rays one- 

 cell wide; fracture hard, fibrous; inodorous; taste slight. 



Powder Reddish; tracheae with bordered pores; sclerenchy- 

 matous fibers long, thin- walled; crystal fibers with monoclinic 

 crystals of calcium oxalate. The coloring principle is insoluble 

 in water but soluble in alcohol and in solutions of the alkalies. 



Constituents. A coloring principle santalin (santalic acid), 

 which occurs in red needles that are insoluble in water, soluble in 

 alcohol, forming a deep red solution which is colored violet with solu- 

 tions of the alkalies. It also contains tannin and several colorless 

 crystalline principles. 



Allied Plants. The African sandal wood or barwood is obtained 

 from P. santalinoides of tropical West Africa. Cam-wood or African 

 red-wood (obtained from Baphia nitida, in Sierra Leone) is also valued 

 on account of its red coloring principle. 



ACACIA. Gum Arabic. A dried, gummy exudation from the 

 stem and branches of Acacia Senegal and probably other species of 

 Acacia (Fam. Leguminosae, sub-fam. Mimosaceae), trees growing in 

 sandy soil and forming forests in tropical Africa. The gum exudes 

 spontaneously from the bark of the tree and is apparently formed 

 by the action of a ferment on the cell-contents, as it does not contain 

 any remains of cell walls. The trees are also incised, which increases 



