10(3 Chemical Experiments on Guaiacum. 



Suspecting the presence of lime in the solution, I added 

 a few drops of oxalate of ammonia, when the liquid imme- 

 diately became turbid, and deposited brown flakes, which, 

 after having been treated with boiling alcohol, yielded traces 

 of oxalate of lime. 



These effects, therefore, indicate the presence of a sub- 

 stance in guaiacum which possesses the properties of ex- 

 tract * ; the action of the re-agent is, however, somewhat 

 modified by a small quantity of lime which is also in solu- 

 tion. 



One hundred grains of guaiacum yielded about nine grains 

 of this impure extractive matter. 



C. Alcohol dissolves guaiacum with facility, leaving some 

 extraneous matter, 'which generally amounts to about five 

 per cent. 



This solution is of a deep brown colour; the addition of 

 water separates the. resin, forming a milky fluid which 

 passes the filter. 



Acids produce the following changes: 



A. Muriatic acid throws down an ash-coloured precipi- 

 tate, which is not redissolved by healing the mixture. In 

 this ca^c the resin appears but little altered. 



B. Liquid oxymuriatic acid, when poured into this solu- 

 tion, forms a precipitate of a very beautiful pale blue colour, 

 which may be preserved unaltered. 



C. Sulphuric acid, when not added in too large a quan- 

 tity, separates the resin of a pale green colour. 



D. Acetic acid does not form any precipitate. This acid 

 is, indeed, capable of dissolving most of the resins. 



E. Nitric acid, diluted with one-fourth of its weight of 

 water, causes no precipitate till after the period of some 

 hours. The liquid at first assumes a green colour, and if 

 water be added at this period, a green precipitate may be 

 obtained : the green colour soon changes to blue, (when, by 

 the same means, a blue precipitate may be obtained ;) it 

 then becomes brown, and a brown precipitate spontaneously 



* By the term c.\lratt, I mean that substance which by chemists is called 

 the extractive principle of vegetables. Vide Thomson's System of Chemistry, 

 2d edit. vol. iv. p. 276'. 



makes 



