Analysis of Benzoin. 153 



He began by digesting it in common alcohol cold. Twenty- 

 five drachms, Avheii several times treated by alcohol, left half a 

 drachm of woody and sandy particles. The alcoholic liquors 

 were then mixed in a glass retort with 48 ounces of water : the 

 alcoholic part was afterwards distilled ofif a.t a very gentle heat. 

 The aqueous residue in the retort was filtered through bibulous 

 paper, which retained a few flakes of a soft resin. The filtered 

 liquid deposited on cooling two drachms and ten grains of ben- 

 zoic acid in a pulverulent state. To the bottom of the vessel 

 there adhered a thin. coating of soft resin or balsam. The eva- 

 poration of the decanted liquor being continued, benzoic acid 

 and resin were still separated : the mother water gave 16 grains 

 of a resinous matter without any trace of extractive matter. 

 The residue of the resin of benzoin which fringed the sides of 

 the retort was redissolved in alcohol, and, after adding water as 

 before, distilled : the filtered liquor again deposited benzoic acid. 

 The weight of the acid separated by the preceding experiments 

 was three drachms. The alcoholic product of the distillation 

 reddened turnsole paper, a proof that some of the acid was vo- 

 latilized in the alcohol. In fact, four ounces of this alcohol 

 left to spontaneous evaporation in a cup gave one grain of ben- 

 zoic acid. 



The viscous matter like l)alsam of Peru was treated by boiling 

 water, filtered, and evaporated. A peculiarly bitter aromatic taste 

 distinguished the residue, which was soluble in boiling water and 

 alcohol, but not in ether. The viscous matter which resisted 

 the boiling water was very soluble in alcohol and ether. This 

 last substance is si/i generis. The purified resin of benzoin is 

 of a brownish-red colour, pale like gumlac in tears, transparent, 

 brittle, and gives a reddish-vvhite dust. It is entirely soluble in 

 alcohol and ether, but not in spirits of turpentine. 



i\I. Bucholz obtained the following products from the 25 

 drachms employed: 



I>rachms. Grains. 



Resin of benzoin 20 50 



Benzoic acid 3 7 



Substance similar to balsam of Peru 25 



Particular aromatic principle soluble in") /^ t, 



water and alcohol J 



Ligneous particles and impurities 30 



25 



M. Bucholz then procured the benzoic acid in the following 



way : He jjoured four parts of alcohol upon one of pulverized 



benzoin m a matrass. After digesting a few days, the alcoholic 



liquor was filtered. It was then introduced into a large glass 



retort' 



