"Hence, since from must of grapes we procure alcohol and carbonic acid, I
have an undoubted right to suppose that must consists of carbonic acid
and alcohol. From these premisses we have two modes of ascertaining what
passes during vinous fermentation: either by determining the nature of,
and the elements which compose, the fermentable substances; or by
accurately examining the products resulting from fermentation; and it is
evident that the knowledge of either of these must lead to accurate
conclusions concerning the nature and composition of the other. From
these considerations it became necessary accurately to determine the
constituent elements of the fermentable substances; and for this purpose
I did not make use of the compound juices of fruits, the rigorous
analysis of which is perhaps impossible, but made choice of sugar, which
is easily analysed, and the nature of which I have already explained.
This substance is a true vegetable oxyd, with two bases, composed of
hydrogen and carbon, brought to the state of an oxyd by means of a
certain proportion of oxygen; and these three elements are combined in
such a way that a very slight force is sufficient to destroy the
equilibrium of their connection."

After giving the details of his analysis of sugar and of the products of
fermentation, Lavoisier continues:--

"The effect of the vinous fermentation upon sugar is thus reduced to the
mere separation of its elements into two portions; one part is oxygenated
at the expense of the other, so as to form carbonic acid; while the other
part, being disoxygenated in favour of the latter, is converted into the
combustible substance called alkohol; therefore, if it were possible to
re-unite alkohol and carbonic acid together, we ought to form sugar."[1]

[Footnote 1: _Elements of Chemistry_. By M. Lavoisier. Translated by