and being dried, becomes
brittle, and somewhat resembles gum. Starch, although found in all
nutritive grains, is only perfect when they have attained maturity, for
before this it is in a state approaching to mucilage, and so mixed with
saccharine matter and essential oils, that it cannot be extracted in
sufficient purity to concrete into masses. Wheat, or such parts of it as
are not used for human food, are usually employed for manufacturing
starch, such as the refuse wheat and bran; but when the finest starch is
required, good grain must be used. This, being well cleaned, and
sometimes coarsely bruised, is put into wooden vessels full of water to
ferment: to assist the fermentation, the vessels are exposed to the
greatest heat of the sun, and the water is changed twice a day, during
eight or twelve days, according to the season. When the grain bursts
easily under the finger, and gives out a milky white liquor when
squeezed, it is judged to be sufficiently softened and fermented. In
this state, the grains are taken out of the water by a sieve, and put
into a canvas sack, and the husks are separated and rubbed off, by
beating and rubbing the sack upon a plank: the sack is then put into a
tub filled with cold water, and trodden or beaten till the water becomes
milky and turbid, from the starch which it takes up from the grain. A
scum sometimes swims upon the surface of the water, which must be
carefully removed; the water is then run off through a fine sieve into a
settling-vessel, and fresh water is poured upon the grains, two or
three times, till it will not extract any more starch, or become
coloured by the grain. The water in the settling-vessels being left at
rest, precipitates the starch which it held suspended; and to get rid of
the saccharine matter, which was also dissolved by the water, the
vessels are exposed to the sun, which soon produces the acetous
fermentation, and takes up such matter as renders the starch more pure
and white. During this process, the starch for sale in the shops
receives its colour, which consists of smalt mixed with water and a
small quantity of alum, and is thoroughly incorporated with the starch;
but this starch is unfit for medicinal purposes. When the water becomes
completely sour, it is poured gently off from the starch, which is
washed several times afterwards with clean water, and at last is placed
to drain upon linen cloths supported by hurdles, and the water drips
through, leavi