on treating Uric with Nitrous Acid, &e. 33 
In effecting this decomposition, and taking care that in the fluid 
no sulphuric acid remains, an acid of a yellowish colour and sour 
astringent taste is obtained. It reddens the tincture of turnsole, 
and when evaporated does not form crystals, but attracts a little 
humidity. The salt of lead from which this acid is extracted, is 
yery soluble in acetic and dilute nitric acid. From many of the 
above characters which this acid substance possesses, it may 
be concluded to be malie acid. It is not, however, easy to con- 
ceive how the malic acid can exist in the brown mass obtained 
by the long action of nitrous on uric acid, while in it there was 
no longer found any trace of oxalic acid; and as this acid is 
formed at the expense of the malic, which is altered by the ni- 
trous acid, so much greater is the force that can thus entirely 
decompose the malic acid. This reflection made me suspect that 
the acid substance was not malic acid, but one of those acids 
which have much affinity with it, among which the illustrious 
Scheele distinguished the lactic acid*. The characteristic dif~ 
ference which he established between these two acids is the in- 
solubility in alcohol of the calcareous salt of the former, and on 
the contrary the solubility of the calcareous salt of the latter. 
Hence, having observed that aleohol projected on the calcareous 
salt which I obtained became turbid with a drop of oxalic acid, 
I concluded it to be lactic acid, which I endeavoured to ascer- 
tain. As the salts of potash and of lead are soluble in alcohol, 
so also is the salt of potash which is obtained in an irregular 
form by the above method; and when the alcohol is evaporated 
by a gentle heat, it is found elegantly crystallized in long and 
slender needles. The regular form is likewise obtained when the 
pure acid is directly united with potash. 
_ To the opinion that the acid obtained may be the lactic acid 
of Scheele, supported by the solubility of its salts in aleohol, it 
may be opposed, that this is perhaps owing to the presence 
of the patticular yellow matter above mentioned; and in fact, 
experiments prove that it at least augments the effect. But it 
may be answered, that the acid obtained by Scheele should not 
be entirely devoid of this matter. Berzelius found lactic acid 
united to a particular matter in all the animal fluids, and it is the 
opinion of this chemist that the acid obtained by Scheele was 
very farfrom being pure. When the yellow solution is extracted 
fom the original brown mass, there remains, as already noticed, 
a blackish matter. This dissolves rapidly in potash, and the al- 
kali is in a great measure neutralized. ‘The solution has a deep 
ruby colour, if it is concentrated and the potash in excess; other- 
wise the colour is a deep yellow. This solution, provided that it 
: * Crell, Ann. part ii, 1785, p. 303. 
Vol. 52. N@. 243. July 1818. C has 
