2 53 
of a newly discovered vegetable acid. 
water is digested over Quassia, and afterwards evaporated 
to dryness, a transparent substance is obtained, which 
differs in its properties from all other vegetable principles : 
this he considers as the bitter principle, and, I believe, 
with very great justice. I found that the liquor obtained by 
digestion, although slightly coloured, was transparent even 
to the end of the evaporation. The resulting mass was nearly 
transparent, and minute in quantity, considering the propor- 
tion of Quassia employed ; and such was its bitterness, that a 
particle placed on the tongue, which could not have exceeded 
~th of a grain, diffused an intense bitterness over the whole 
mouth and fauces. 
This matter was heated with nitric acid ; it dissolved with 
effervescence, and the bitterness was no longer sensible. The 
remaining substance formed a precipitate in acetate of lead, 
which possessed all the properties of malate of lead : and it 
appeared that no other than the malic acid was produced. 
With this experiment the following agrees in a remarkable 
manner. 
Five ounces of white sugar, and an equal weight of very 
strong nitric acid were mixed in a retort. Without the ap- 
plication of external heat the action commenced, and soon 
became violent. When cold, the residual matter was found 
to be thick and tenacious ; its taste was sour, and extremely 
bitter. The malic acid being abstracted from a portion of 
this by means of lime, it was found that the bitterness, now 
no longer disguised by acidity, had become intense. The 
other portion, w hich had not been saturated with lime, by being 
treated with more nitric acid, lost all its bitterness, and oxalic 
acid was formed. In this experiment it appears, that by some 
i 
