498 OLEO-RESINS 



marked taste it produces, when swallowed, a burning sensation 

 in the throat. 



Balsam of Peru is heavier than water, its specific gravity varying 

 within narrow limits viz. from 1-137 to 1-158, being usually between 

 1'140 and 1*158, and this forms a valuable means by which adultera- 

 tion can be detected, for many liquids that might be used for that 

 purpose are lighter than water, and would appreciably depress the 

 gravity. It is soluble in chloroform, and also in an equal volume of 

 90 per cent, alcohol, but with a larger proportion of the latter the 

 mixture becomes turbid. It is practically insoluble in water, that 

 liquid removing from it only a little cinnamic acid. 



Its physical characters are so well marked, especially the odour 

 and taste, that the drug is easy to recognise, but the detection of 

 adulteration, especially with inferior qualities of the drug, which 

 appears to be more or less regularly practised, is a more difficult 

 problem. 



Constituents. Balsam of Peru consists essentially of an oily fluid 

 portion mixed with a dark resin. The fluid portion (cinnamein) 

 constitutes from 56 to 66 per cent, of the commercial drug, and consists 

 of benzyl benzoate and benzyl cinnamate in the proportion of about 

 three of the former to two of the latter, although this varies. Both 

 esters are colourless, crystalline aromatic bodies which readily liquefy 

 on heating. 



The resinous portion, amounting to about 28 per cent, of the com- 

 mercial drug, is composed of an alcohol, peruresinotannol, combined 

 with cinnamic and a little benzoic acid. 



The drug also contains an alcohol, peruviol (= nerolidol) which 

 possesses a sweet odour and taste, traces of vanillin, and free cinnamic 

 acid. 



Uses. Balsam of Peru is antiseptic and disinfectant. It is chiefly 

 used as an external application in certain skin diseases and for bed 

 sores. It has also been employed as a stimulant and disinfectant 

 expectorant in bronchitis. 



Adulterants. Balsam of Peru is, from its nature and high price, 

 liable to adulteration, chiefly with such liquids as alcohol, fixed oils, 

 turpentine, copaiba, gurjun balsam, and the like. Any such admixture 

 lowers the specific gravity, and can generally be detected by this 

 means. Alcohol can be removed from the balsam by shaking it with 

 water, which with the genuine drug should cause no appreciable 

 diminution in volume. The presence of copaiba and of gurjun balsam 

 can be detected by taking advantage of the insolubility of the resin of 

 balsam of Peru in carbon disulphide. One part of carbon disulphide 

 makes a clear mixture with three parts of balsam of Peru, but on the 

 further addition of nine parts of carbon disulphide the resin should 

 separate leaving a clear yellow non-fluorescent liquid which on 



