Analysis of aloes. 3Q5 



heating this with a certain quantity of lime and water, am* 

 monia was very perceptibly evolved. 



§ VI. Weak acids have no very striking action on aloes, yet Actioa of acid 

 they dissolve it better than water, which whitens the solu-""^''''-'^- 

 tion of aloes in distilled vinegar. The mineral acids act on 

 it much more powerfully. Nitric acid dissolves it very 

 >?^ell without heat, producing a deep red liquid, which 

 water precipitates abundantly. 



Ten gram. [154-4 grs.] of aloes were treated in a retort Nitric acid. 

 with 80 gram. [l23o grs. of nitric acid at 36°, taking care to 

 raise the fire cautiously. The action was brisk, and abund- 

 ance of red fumes Avcre evolved. When these disappeared, 

 tlie retort was removed from the fire. The liquid contained 

 in it was of a deep yellow colour, and on cooling depo- 

 sited a pretty|large quantity of a yellow flocculent substance. 

 Being evaporated to the consistence of honey, it was di- 

 luted with water, and filtered. A yellow substance re- Yellow- arid 

 mained on the filter, which, after having been well washed P'^'^'^"^'^'^- 

 and dried, amounted to about a fourth of the aloes em- 

 ployed. This appeared to be an acid, analogous to the 

 yellow, acid, and detonating matter which Fourcroy and 

 Vauquelin obtained by the action of nitric acid and animal 

 substances, but differing slightly in several respects. 



The yellow aloetic acid, well washed and dried, is of aits properties. 

 fine yellow colour, and extremely bitter. It does not crys- 

 tallize. It reddens litmus paper, and effervesces with al- 

 kaline carbonates. It has a pleasant aromatic smell, par- 

 ticularly when gently heated. It melts like nitre, emits an 

 aromatic vapour mixed with bitterness, and leaves an 

 abundant coally residuum. Distilled with a gentle heat, it 

 furnished all the products of vegetable substances, and 

 finally detonated with a purplish flame. A very bulky 

 coal remained, equal to a third of the matter employed. 



This acid is very little soluble in water. Jt required 1250 

 times its weight of water at 10" R. [54*5 F.] for i(s com- 

 plete solution. .This was of the fine red colour of arterial 

 blood. Muriate of fin produced in it a precipitate of the 

 coloirr of wine lees. The sulphates of iron and of copper 

 brightuned the colour. 



Alcohol 



