th it a given amount of fluid, by which each atom of flour is
surrounded with a thin film of moisture, in order to hydrate the starch,
to dissolve the sugar and albumen, and to develop the adhesiveness of
the gluten, thus binding the whole into one coherent mass termed
_dough_, a word from a verb meaning to wet or moisten. If nothing more
be done, and this simple form of dough be baked, the starch granules
will be ruptured by the heat and thus properly prepared for food; but
the moistening will have developed the glue-like property of the gluten
to the extent of firmly cementing the particles of flour together, so
that the mass will be hard and tough, and almost incapable of
mastication. If, however, the dough be thoroughly kneaded, rolled very
thin, made into small cakes, and then quickly baked with sufficient
heat, the result will be a brittle kind of bread termed unleavened
bread, which, although it requires a lengthy process of mastication, is
more wholesome and digestible than soft bread, which is likely to be
swallowed insufficiently insalivated.

The gluten of wheat flour, beside being adhesive, is likewise remarkably
elastic. This is the reason why wheat flour is much more easily made
into light bread than the product of other cereals which contain less or
a different quality of gluten. Now if while the atoms of flour are
supplied with moisture, they are likewise supplied with some form of
gaseous substance, the elastic walls of the gluten cells will become
distended, causing the dough to "rise," or grow in bulk, and at the same
time become light, or porous, in texture.

This making of bread light is usually accomplished by the introduction
of air into the dough, or by carbonic acid gas generated within the
mass, either before or during the baking, by a fermentative or chemical
process.

When air is the agency used, the gluten, by its glue-like properties,
catches and retains the air for a short period; and if heat is applied
before the air, which is lighter than the dough, rises and escapes, it
will expand, and in expanding distend the elastic glutinous mass,
causing it to puff up or rise. If the heat is sufficient to harden the
gluten quickly, so that the air cells throughout the whole mass become
firmly fixed before the air escapes, the result will be a light, porous
bread. If the heat is not sufficient, the air does not properly expand;
or if before a sufficient crust is formed to retain the air and form a