ON VEGETABLE CHEMISTRY. 
335 
a considerable elevation of temperature that I have ever been 
able to procure spirit from such berries. 
At this period, which is the state of perfect maturity, the 
proportion of malic acid is small, not one-third of that con- 
tained in the immature state; and I am inclined to the opi- 
nion, that it is either some change in the composition of the 
malic acid, or a peculiar combination formed between it and 
the mucilage which will at once account for its apparent 
absence and the color of the fruits. In the next stage we 
find different appearances and results. The vessels which 
carried on the circulation between the parent tree and its de- 
pendent berry are now obliterated, vital action ceases in the 
fruit, and chemical changes supervene. The thick layer of 
mucilage lining the husk breaks down and softens into a loose 
pulp, the husk becomes thin and permeable, absorbs oxygen, 
and rapidly decomposes. It requires only a slight alteration 
in the constituents of the alcohol, and vinegar is formed di- 
rectly. Thus, 1 eq. of the former, consisting of 4 c. + 6 h.-f- 
2 o. if added to 4 eq. of oxygen, produces 1 eq. of acetic 
acid=4 c. + 3 h. + 3 o. and 3 eq. of water. This is a change 
which may be explained by theory, but which is equally sub- 
stantiated by experiment; for when the alcohol disappears, 
vinegar and water invariably supply its place. 
The presence of alcohol in ripe fruit is rather a remarkable 
circumstance, and I am not aware of its having been described 
before. But in the mode of investigation which I have adopted, 
(precisely as described in this paper,) I do not think that any 
mistake could arise, or the spirit have been a product instead 
of an educt. Had I employed ordinary distillation, the alco- 
hol, as long since shown by Gay-Lussac, would have been 
much more abundant, the greater part of it being formed du- 
ring and not prior to the distillation. But by distilling in va- 
cuo, that inaccuracy is obviated; and by separating the alcohol 
without any distillation whatever, an additional proof of its 
existence is furnished. 
I think it not improbable that future investigators will de- 
tect spirit in most fruits, and I am far from thinking that 
