Analytical Essay on Asparagus. 37 
trated sulphuric acid diluted with four parts of water. Some 
moments after mixture the mass became more liquid, and 
took a beautiful rose colour. J heated it slightly to facili- 
tate the decomposition; and after some hours digestion the 
liquor was filtered; it still contained a little sulphuric acid, 
which I separated by means of caustic barytes. I again fil- 
tered it, and after having evaporated it to the consistence 
of thick syrup, I treated it with alcohol, fearing that. this 
acid had carried along with it in solution a little animal 
matter (mucilage, or of some other substance) extraneous 
to its nature, particularly a calcareous salt which was depo- 
sited in small, finc, and white needles. I presume that this 
acid is one of its constituent principles. T afterwards eva- 
porated the alcohol without making it boil, managing the 
fire very carefully towards the close of the experiment. I 
repeated this operation until, by again dissolving it in spirit 
of wine, it did not form any precipitate at all: a precaution 
necessary to have this acid in the purest pussible state. We 
_ might suspect that the acetate of lead had precipitated at the 
same time with the acid a great quantity of the matter which 
M. Antoine regards as of an animal nature, and that con- 
sequently the sulphuric acid had set free a good deal of the 
acetous acid which was mixed with that of the asparagus; but 
it is to be remarked that this pretended gluten is not precipi- 
tated, at least for the greater part, until the juice has acquired 
a certain degree of concentration. The experiment I am about 
to relate will demonstrate this very distinctly: [ poured into 
the juice so great a quantity of the acetate of lead as must 
have separated all the acid. I afterwards treated the liquor 
with sulphuretted hydrogen. It formed an abundant black 
precipitate of sulphuret of lead, which I separated by the 
filter ; 1 evaporated it, and after some time | again obtained 
a precipitate by the same reagent. 
The principal properties which I have recognised in the 
acid I have mentioned are: a colour more or less brown ac- 
cording to the degree of concentration, and very acid, leaving 
in the mouth a peculiar taste very disagreeable. It also 
gives out during its heating a very pungent odour, which 
afterwards becomes blended with another extremely fetid, 
C3 and 
