226 Analysis of Aloes, 



bitterness and its other properties : this solution becatfrtj 

 frothy on being shaken. 



One hundred and forty-eight grammes of water at 3'&°-\- & 

 of Reaumur were sufficient entirely to dissolve four grammes 

 of aloes, with the exception of one decigramme of an im- 

 pure ligneous matter : the liquor became turbid as it cooled, 

 and deposited part of the matter dissolved. This solubility 

 of aloes in water increases in such a manner, in consequence 

 of heat, that we may obtain a syrupy solution, which then 

 ceases to deposit any sediment. 



When tried by the re- agents, the solution of aloes in 

 water presented the following effects : 



1. It reddened turnsole tincture in a very marked man- 

 Tier. 



2. The alkalis and lime water render the colour darker^ 

 without precipitating any thing from it. 



3. The sulphate of iron produces a brown colour, and a 

 precipitate of the same colour soOn afterwards. 



4. The decoction of gall nuts forms a flaky yellowish 

 precipitate. The supernatant liquor is much less bitter, and 

 weaker in colour. 



5. The subacetatje of lead also produces a precipitate in 

 this liquor. The supernatant liquor becomes almost co- 

 lourless. 



6. The nitrate of copper and of lead and muriate of tin 

 produce slight sediments in it, but which do not appear to 

 me to be true chemical combinations; for solutions of 

 muriate of soda and of the other neutral salts produce quite 

 as much. These saline matters therefore acton the solution 

 of aloes in the same manner as upon that of tannin in 

 water, bv weakening the action of this fluid on the not 

 very soluble matter which is dissolved in it. 



The above solution of aloes, which was of a fine golden 

 colour, was put into three bottles : the first, which held a 

 pint, was entirely filled with it and well corked : the second, 

 which was* of the same capacity, was half rilled and left 

 open : the third, being a medicine phial, was one quarter 

 filled. In two months and a half the following phaenomena 

 were observed : The liquor of the first bottle had preserved 

 its colour without alteration; that of the second was a very 

 dark red, and was discoloured by the oxygenized muriatic 

 acid, which produced a flaky precipitate. Jn the third a 

 quantity of mucus was formed. The coloured liquor of 

 these two last bottles had acquired a kind of viscositv. It 

 would seem, in fact, that there is a substance produced ana- 

 logous to gelatine; for the decoction of gall nuts formed in 



it 



