512 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



wood and bark as a result of certain pathological phenomena. Among 

 special histological characters the following are of some importance. 

 The cork originates either in, or below the pericycle, the latter usually 

 containing isolated groups of bast fibers. The walls of the tracheae 

 possess scalariform perforations or simple pores, and the wood fibers 

 are usually marked by bordered pores. The stomata on the leaves 

 are usually unaccompanied by subsidiary cells, although when 

 present they are parallel to the pore. Non-glandular hairs are either 

 stellate or in the form of peltate scales. . Calcium oxalate is secreted 

 in the form of ordinary crystals or as rosette aggregates. Glandular 

 hairs are wanting. 



BENZOINUM. Benzoin. A balsamic resin obtained from Styrax 

 Benzoin, and probably other species of Styrax (Fam. Styracacese), 

 trees indigenous to Java, Sumatra and Siam. The resin flows from 

 incisions made in the bark, hardens, and is then collected, the com- 

 mercial varieties being known as Siam and Sumatra Benzoin, the 

 former being preferred. The composition of the resin varies according 

 to the age of the tree, the youngest trees yielding the best product. 

 The constituents of the commercial resin are not found in the tissues 

 of the tree, but appear to develop as a pathological product due to an 

 injury of the trees resulting from the manner of incising the bark, 

 although probably the exposure of the resin to the air has an influence 

 on the constituents. 



Sumatra Benzoin. In irregular masses composed of yellowish- 

 or reddish-brown tears of variable size and a reddish-brown and 

 translucent or grayish-brown and opaque matrix; brittle, the tears 

 internally being milky w r hite; becoming soft on warming, and yielding 

 benzoic acid on sublimation; odor agreeable, balsamic, resembling 

 that of styrax; taste slightly aromatic. About 75 per cent is soluble 

 in a solution of potassium hydroxide or in 95 per cent alcohol. 



Siam Benzoin occurs in concavo-convex tears; it has a vanilla- 

 like odor and is almost completely soluble in solutions of the alkalies 

 or in alcohol; it is further distinguished from the Sumatra variety 

 in not containing cinnamic acid, and therefore does not yield benzalde- 

 hyde on boiling an acidulated solution with potassium permanganate. 



Powder. Light reddish-brown; consisting mostly of irregular, 

 nearly colorless purplish-red fragments, containing rosette aggre- 

 gates of small rod-like crystals. Upon heating, in a watch crystal or 

 on a slide and covering with a slide microsublimate crystals of benzoic 

 acid are obtained (Fig. 36). 



Constituents of Sumatra Benzoin. About 75 per cent of a resin- 

 ous substance, benzoresin, which consists of two esters: (a) an ester 



