In boiling water, the skins crack, and the inside swells and becomes gummy.

Long boiling is thus an essential for all starchy foods.
Bread proper is simply flour, water, and salt, mixed to a firm dough and baked.

Such bread as this, Abram gave to his angelic guests, and at this day the Bedouin Arab bakes it on his heated stone.

But bread, as we understand it, is always lightened by the addition of yeast or some form of baking-powder, yeast making the most wholesome as well as most palatable bread.

Carbonic-acid gas is the active agent required; and yeast so acts upon the little starch-granules, which the microscope shows as forming the finest flour, that this gas is formed and evenly distributed through the whole dough.