thus
stated:--A body, A, without giving to, or taking from, another
body, B, any material particles, causes B to decompose into other
substances, C, D, E, the sum of the weights of which is equal to the
weight of B, which decomposes.

Thus, bitter almonds contain two substances, amygdalin and synaptase,
which can be extracted, in a separate state, from the bitter almonds.
The amygdalin thus obtained, if dissolved in water, undergoes no
change; but if a little synaptase be added to the solution, the
amygdalin splits up into bitter almond oil, prussic acid, and a kind
of sugar.

A short time after Cagniard de la Tour discovered the yeast plant,
Liebig, struck with the similarity between this and other such
processes and the fermentation of sugar, put forward the hypothesis
that yeast contains a substance which acts upon sugar, as synaptase
acts upon amygdalin. And as the synaptase is certainly neither
organized nor alive, but a mere chemical substance, Liebig treated
Cagniard de la Tour's discovery with no small contempt, and, from
that time to the present, has steadily repudiated the notion that the
decomposition of the sugar is, in any sense, the result of the vital
activity of the _Torula_. But, though the notion that the _Torula_ is
a creature which eats sugar and excretes carbonic acid and alcohol,
which is not unjustly ridiculed in the most surprising paper that
ever made its appearance in a grave scientific journal[1], may be
untenable, the fact that the _Torulae_ are alive, and that yeast does
not excite fermentation unless it contains living _Torulae_, stands
fast. Moreover, of late years, the essential participation of living
organisms in fermentation other than the alcoholic, has been clearly
made out by Pasteur and other chemists.

[Footnote 1: "Das entraethselte Geheimniss der geistigen Gaehrung
(Vorlaeufige briefliche Mittheilung)" is the title of an anonymous
contribution, to Woehler and Liebig's "Annalen der Pharmacie" for
1839, in which a somewhat Rabelaisian imaginary description of the
organization of the "yeast animals" and of the manner in which their
functions are performed, is given with a circumstantiality worthy
of the author of Gulliver's Travels. As a specimen of the writer's
humour, his account of what happens when fermentation comes to an end
may suffice. "Sobald naemlich die Thiere keinen Zucker mehr vorfinden,
so fressen sie sich gegenseitig selbst auf, was durch eine eigene
Manipulatio