er plants have their acrid juices or bitter particles diminished
by covering them from the light by what is termed blanching them, as the
stems and leaves of cellery, endive, sea-kale. The former method either
extracts or decomposes the acrid particles, and the latter prevents them
from being formed. See Botanic Garden, Vol. I. additional note XXXIV. on
the Etiolation of vegetables.

5. The art of cookery, by exposing vegetable and animal substances to heat,
has contributed to increase the quantity of the food of mankind by other
means besides that of destroying their acrimony. One of these is by
converting the acerb juices of some fruits into sugar, as in the baking of
unripe pears, and the bruising of unripe apples; in both which situations
the life of the vegetable is destroyed, and the conversion of the harsh
juice into a sweet one must be performed by a chemical process; and not by
a vegetable one only, as the germination of barley in making malt has
generally been supposed.

Some circumstances, which seem to injure the life of several fruits, seem
to forward the saccharine process of their juices. Thus if some kinds of
pears are gathered a week before they would ripen on the tree, and are laid
on a heap and covered, their juice becomes sweet many days sooner. The
taking off a circular piece of the bark from a branch of a pear-tree causes
the fruit of that branch to ripen sooner by a fortnight, as I have more
than once observed. The wounds made in apples by insects occasion those
apples to ripen sooner; caprification, or the piercing of figs, in the
island of Malta, is said to ripen them sooner; and I am well informed, that
when bunches of grapes in this country have acquired their expected size,
that if the stalk of each bunch be cut half through, that they will sooner
ripen.

The germinating barley in the malt-house I believe acquires little
sweetness, till the life of the seed is destroyed, and the saccharine
process then continued or advanced by the heat in drying it. Thus in animal
digestion, the sugar produced in the stomach is absorbed by the lacteals as
fast as it is made, otherwise it ferments, and produces flatulency; so in
the germination of barley in the malt-house, so long as the new plant
lives, the sugar, I suppose, is absorbed as fast as it is made; but that,
which we use in making beer, is the sugar produced by a chemical process
after the death of the young plant, or which is made more expeditiou