20 On the Nature, $c. of a newly-discovered vegetable Acid. 
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 application of 
external heat the action commenced, and soon became violent. 
When cold, the residual matter was found to be thick and ten: - 
cious; 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, which had not been 
saturated with lime, by being treated with more nitric acid, lost 
all its bitterness, and oxalic acid was formed. In this experi- 
ment it appears, that by some action of nitrous acid on sugar, @ 
bitter substance and malic acid were produced together; that 
by the further action of nitrous acid, the bitter substance dis- 
appeared, and acid appeared in its stead. 
The foregoing conjectures correspond also with the fact, that 
by the action of certain substances on each other, the bitter 
principle is evolved at the same time with those acids which I 
suppose to have been produced from that compound basis: and 
the appearance of both at the same time may be accounted for 
by admitting that the conversion was not complete. Thus, if 
alcohol be distilled with nitrous acid, a liquor is produced which 
has a-sweet taste. If this liquor be re-distilled with another 
portion of acid, a bitter liquor comes over. And if this bitter 
liquor be distilled a third time with a fresh portion of nitrous 
acid, crystals of oxalic acid make their appearance in the re- 
siduum. ‘This series of changes bears a striking resemblance to 
that produced by the action of nitrous acid on sugar. 
Haussman observed, that when nitric acid is digested with 
indigo, a very bitter substance results, to which Welther gave the 
name of Amer: in this process, oxalic acid is also formed. 
The vegetable acids are even formed by the action of nitrous 
acid on animal substances; in the instance of muscle we obtain 
the above-mentioned Amer with oxalic acid. In bile the bitter 
principle is already formed; when aeted on by nitrous acid, 
oxalic acid is produced. 
- On examination we shali not be at a loss to find operations 
analogous to some of the preceding, taking place naturally in 
the vegetable kingdom. The Pyrus Malus or common crab- 
apple, while young, is very bitter, and has little sourness : as the 
fruit advances towards maturity, the taste becomes propor- 
tionately sour, and the bitterness diminishes. The young berries 
of the Sorbus aucuparia also are bitter, contain but one acid, 
and even that in small quantity: when the berry is ripe, it con- 
tains two acids, the combined quantity of both is considerable, 
but 
