RESINA BENZOE. 407 



has the aspect of a reddish-brown granite. There is always a certain 

 admixture of bits of wood, bark, and other accidental impurities. 



The white tears when broken, display a stratified structure with 

 layers of greater or less translucency. By keeping, the white milky 

 resin becomes bro"wn and transparent on the surface. 



Siam benzoin is very brittle, the opaque tears showing a slightly 

 wax}^, the transparent a glassy fracture. It easily softens in the mouth 

 and may be kneaded with the teeth like mastich. It has a delicate 

 balsamic, vanilla-like, fragrance, but very little taste. When heated it 

 evolves a more pow^erful fragrance, together with the irritatmg tumes 

 of benzoic acid ; its fusing point is 75^ C. The presence of benzoic acid 

 may be shown by the microscopical examination of splinters of the 



resin under oil of turpentine. , 



Siam benzoin is imported in cubic blocks, which takes their torm 

 from the wooden cases- in which they are packed while the resm is 



_^. ^.^ Prior to the renewal of direct commercial 



intercourse with Siam Tn 1853, this was the sort of benzoin most com- 

 monly found in commerce. - 



It is imported in cubic blocks exactly like the preceding, trom 

 which it differs in its generally greyer tint. The mass however when 

 the drug is of good quality, contains numerous opaque tears, set in a 

 translucent, greyish-brown resin, mixed with bits of wood and baric 

 When less good, the white tears are wanting, and the proportion ol 

 impurities is greater. We have even seen samples consisting ainiost 

 wholly of bark. In odour, Sumatra benzoin is both weaker and less 

 agreeable than the Siam drug, and generally falls short of it in purity 

 and handsome appearance, and hence commands a much lower price. 

 The greyish-brown portion melts at 95°, the tears at 8o ^• 



A variety of Sumatra benzoin is distinguished ^7 *?^.^,^^^"^^,^^^^^ 



still soft. 



Ben 



seen it of \ 



long), the 



Fenanq Benjamin or ^omx-mciiing ncnju-n... ., ^ -- - 

 vevy fine quality, full of white tears (some of them two inches 

 intervening resin being greyish.^ The odour is veiy agree- 



or the usual 



able, and perceptiblv different from that of Siam benzoin, or the usuai 

 Sumatra sort. Whether this drug is produced^ in Sumatra and oy 

 Styrax Benzoin we know not ; but it is worthy of note that ^.sw&rt^n- 

 ticidata Miq., occurring in Western Sumatra has the ^ame "ame 

 name (Kajo} Keminjan) as S. Benzoin, and that Miquel remarks ol 



Benzoin consists mainly of amorphous 



Compositio 



v^nemicai Composition— xsenzum w^^^x^vk. ^-^ ^ elirrlitJv acid 

 resins perfectly soluble in alcohol and in potash, ^^f ^"^ f^^^^; of 

 properties, and differing in their behaviour to solvents^ JliTof water 

 the drug are boiled with one part of caustic hme and 20 l-i ts of ^^^^^^^ 

 lienzoin acid is removed. From the residue the excess oi 



washed 



dissolved by hydrochloric acid, and the remaining resins 



dried. About nn^-tbird of them will be found readily solnW^ m etner 



the prevailing portion dissolves in alcohol, and a small amount remains 



undissolved. 



! I" the rmc Learjer, May 2, 1874, the //here ..re 8 -es. of this chug offered 



pnces are quoted thus :-Siani Gum Ben- at Pubbc ^|^^; j'*^;^^^,,^,,^, iSGO. 474. 



jamm, 1st aud 2ik1 qualities, £10 to £28 per » -r'""' ■^"""' 

 Wt.; Sumatra, 1st and 2nd, £7 10s. to £12. 



