BENZOIN 465 



new wood in which a ring (or sometimes two rings) of oleo-resin ducts 

 are formed. By the breaking down of the tissue intervening between 

 the ducts large schizolysigenous ducts are produced in which con- 

 siderable quantities of oleo-resin are secreted. These ducts open on to 

 the wounded surface over which their secretion is discharged. Similar 

 ducts are also formed in the bark. The benzoin thus formed partly 

 accumulates between the bark of the tree and the trunk and partly 

 exudes from the incisions ; it is allowed to get firm and is then collected, 

 bought by Chinese traders, softened by heat or hot water, and packed 

 in oblong boxes, being often, it is said, mixed with vegetable debris in 

 the course of repacking. 



Sumatra benzoin occurs in masses consisting of opaque, white tears 

 embedded in a dull, greyish- brown, or sometimes reddish-brown matrix. 

 It possesses an agreeable, though not very powerful odour, recalling 

 storax, and a slightly acrid taste. When cautiously heated it melts 

 and evolves whitish irritating fumes of benzoic and cinnamic acids. 

 When a little of the crushed resin is warmed with alkaline solution 

 of potassium permanganate benz aldehyde is evolved, indicating the 

 presence of more than traces of cinnamic acid in the drug. 



Sumatra benzoin is frequently contaminated with pieces of bark 

 and other debris, especially in the angles and round the sides of the 

 box in which it is packed. 



Good Sumatra benzoin should not contain more than 10 per cent, 

 of substances insoluble in alcohol, whilst inferior qualities often yield 

 up to 30 per cent. ; it should also not afford more than 5 per cent, of 

 ash. 



Constituents. Sumatra benzoin consists principally of two alcohols 

 combined with cinnamic acid, and associated with free benzoic and 

 free cinnamic acid. Of the two alcohols, one, benzoresinol, is 

 probably identical with the siaresinol of Siam benzoin ; the nature of 

 the other is not definitely known ; it has been stated to be sumaresino- 

 tannol, but this alcohol may have been produced from the alcohol 

 originally present (? lubanol) by oxidation during the extraction 

 (compare Siam benzoin). The drug contains, in addition, traces of 

 benzaldehyde, vanillin (1 per cent.), phenylpropyl cinnamate, styrol, 

 and styracin, all of which combine to produce its particular fragrance. 



The total amount of aromatic acids present in the commercial drug, 

 freed from vegetable debris and moisture, averages 26 per cent., free 

 cinnamic acid 10-3, combined cinnamic acid 7-3, free benzoic acid 

 6-5 and combined benzoic acid 2-5. 



SIAM BENZOIN 



Description. This variety of benzoin is collected in the Siamese 

 province of Luang Prabang, in the neighbourhood of the Mekong 



30 



