of a newly discovered vegetable acid. 237 
acids. I examined this fruit in a similar manner, but no 
crystals were produced. 
Vauquelin detected malic acid in a variety of plants, but 
in none so abundantly as the Sempervivum Tectorum. In 
the juice of this plant, it is united to lime in the state of a 
supersalt.* 
Malate of lead was formed by pouring solution of acetate 
of lead into the filtered juice of this plant. The precipitate, 
when washed with boiling water, deposited on cooling, the 
the same subtile powder as usual, but no crystals. Nor 
were any obtained when the malate was partially decomposed 
by sulphuric acid, in the manner already described. 
Scheele found that the berries of the Sambucus Nigra, 
contain the malic acid unmixed with any other. I therefore 
examined their very mucilaginous juice, but could not pro- 
duce crystals. 
As in my experiments on apples I had obtained crystals, I 
wished to try what effect the vinous fermentation might have 
on their juice. The process was repeated with cyder, but I 
was surprised to find, that although a malate of lead was 
obtained, the property of forming crystals had been destroyed. 
From various conjectures it appeared possible, that the 
berries of the Sorbus while very young, might perhaps con- 
tain a malic acid that would furnish few or no crystals. In the 
beginning of August (1812) the berries being still green, I 
made an infusion of them, which after filtration afforded a pre- 
cipitate with acetate of lead. Boiling water produced no cry- 
stals, nor did the mass become hard as on former occasions. 
Seven varieties of malic acid had now been examined., 
* Annales de Chirrrie, Tom. xxxiv. 127. 
