102 On the Existence of a Combination of Tannin 



properties and the same results uith tho?e of garden beans j 

 we sha.l therefore dispense with any furtlier details on this 

 head. 



§ I V^. Examination of the Leaves of the Indian Chesmit-tree. 



The leaves of the chesnut-trce, when deprived bv alcohol 

 of ail which was soluble in ii, having been afterwards sub- 

 jected to the action of boiling water, communicated to it a 

 light-bro'.vn colour, viscosity, and the property of frothing 

 on agitation. 



Tins liquor, when evaporated to drvncss, left a small ^'|u:^n- 

 tity of brownish matter, which was attached to the capsule 

 in a thin shining laver like a gum, which burned with a 

 crackling noise, exhaling a fetid vapour sensiblv ammo- 

 iiiacal. Its solution in water prccipitaied iron black, and 

 the acetate of lead ve'low, but produced no effect in glue, 

 nor in the infusion of gall nuts. 



We are of opinion that this substance is also a combina- 

 tion of animal matter and of tannin insoluble in alcohol, 

 and by no means a gum, as the appearances denote; and 

 this combination, as is the case with the pellicles of sardeii 

 beans and lentils, is accompanied by a superabundance of 

 tannin, which alcohol takes up. Thus, when we treat these 

 substances directlv bv water, the free acid and tannin favour 

 the solubility of those combinations saturated with the ani- 

 Tiiai matter and tannin, which for the greater part remain 

 insoluble, in the case in which we first treat these vegetable 

 matters with alcohol. 



The leaves of the chcsnut-tree, when successively freed 

 by alcohol and bv water of every thing which is soluble in 

 these tv\o menstrua, and when dried and afterwards distilled, 

 furni>hed an ammoniacal vapour so strong as to be scarcely 

 supportable, and a very alkaline liquor. This last, wfien 

 saturated b'y the muriatic acid, precipitated the solution of 

 sulphate of iron in blackish blue ; which proves that there 

 still remained in these leaves a certain quantity of the com- 

 bination of animal matter and tannin, which neither the 

 alcohol nor the water could dissolve. 



^ V, Attempts made to imitate the vegetable Compound, 

 above described. 



Althouiih we were well convinced, by the properties 

 which we have detailed, and by various other experiments 

 on the leaves of the chesnut-tree, that the matter in ques- 

 tion is a true cumbination of animal principle and tannin, 



we 



