36 Analytical Essay on Asparagus. 
dant, since he assures us that this alcohol contains malate 
. of potash and of lime in manifest quantities. I observed, on 
the contrary, that the aqueous solution precipitated a larger 
quantity by the same reagent ; and what surprised me much 
more was, that neither the one nor the other of these preci- 
pitates was resoluble in vinegar; from whence I was able 
to conclude that it was not malate of lead, or at least that it 
was not pure. It is true, however, that the animal matter 
might very much alter the result. I again consulted the 
memoir of M. Antoine, to know if he had made mention 
of this experiment; and I saw he had, but only to support 
his opinion, that malic acid exists in asparagus. I believe 
he has been deceived on this point ; for we know that ma- 
late of lead dissolves easily in vinegar, and that it is even a 
test employed to detect the presence of sulphate of lead in 
vinegar. 
Suspecting that there existed in the juice of asparagus a 
little earth, I treated a portion of the alcoholic liquor, pro- 
perly evaporated, with the sulphuric acid diluted with three 
parts of water. IT proceeded to distillation, and there passed 
into the receiver am acid Jiquor, which did not precipitate 
the metallic solutions nor those of barytes, &c.; in a word, 
easy to be recognised as vinegar. 
The ashes of this part of the extract, which was soluble 
in alcohol, were composed, in a great measure, of potash 
and a little lime ; whence it seems natural to conclude that 
the acetic acid was combined with the potash, and that the 
supposed malic acid was combined with the hme; for I 
ought here to mention that this calcareous salt, whatever it 
may be, has the property of dissolving in acetous acid, and 
that the alcoho] always preserved a portion of it free. 
The acid contained in the juice of asparagus appearing to 
have some properties different from those assigned to known 
acids, I directed my attention chiefly to this point, and en- 
deavoured to procure it in a state of purity. For this pur- 
pose I took some juice of asparagus filtered and coagulated 
by heat ; I poured upon it the acetate of lead until it ceased 
to form any more precipitate: this, being collected and well 
washed, was treated with a third of its weight of concen- 
trated 
