which happens to be propounded exactly apropos to this matter of
fermentation--that no matter is ever lost, but that matter only changes
its form and changes its combinations--he endeavoured to make out what
became of the sugar which was subjected to fermentation. He thought he
discovered that the whole weight of the sugar was represented by the
carbonic acid produced; that in other words, supposing this tumbler to
represent the sugar, that the action of fermentation was as it were the
splitting of it, the one half going away in the shape of carbonic acid,
and the other half going away in the shape of alcohol. Subsequent
inquiry, careful research with the refinements of modern chemistry,
have been applied to this problem, and they have shown that Lavoisier
was not quite correct; that what he says is quite true for about 95 per
cent. of the sugar, but that the other 5 per cent., or nearly so, is
converted into two other things; one of them, matter which is called
succinic acid, and the other matter which is called glycerine, which
you all know now as one of the commonest of household matters. It may
be that we have not got to the end of this refined analysis yet, but at
any rate, I suppose I may say--and I speak with some little hesitation
for fear my friend Professor Roscoe here may pick me up for trespassing
upon his province--but I believe I may say that now we can account for
99 per cent. at least of the sugar, and that 99 per cent. is split up
into these four things, carbonic acid, alcohol, succinic acid, and
glycerine. So that it may be that none of the sugar whatever
disappears, and that only its parts, so to speak, are re-arranged, and
if any of it disappears, certainly it is a very small portion.

Now these are the facts of the case. There is the fact of the growth of
the yeast plant; and there is the fact of the splitting up of the
sugar. What relation have these two facts to one another?