The colours of Indian corn usually depend on that of the epidermis or hull, and sometimes on that of the oil. If the epidermis be transparent, the colour may depend either upon the oil, or the combined particles of which the corn is composed; but if the hull be opaque, the grain will present the same colour. For example, the yellow colour of the golden Sioux is derived from the yellow colour of the oil; and the Rhode Island white flint-corn on the colourless particles of its starch and oil, which are distinctly seen through its transparent hull; but red and blue corn owe their lively hues to the colours of their epidermis, and not to the oil.
The proportions of oil in corn, as far as it has been examined, varies from an entire absence to eleven per cent., according to the varieties employed.
When corn is hulled by means of potash ley, a portion of the oil is converted into soap, and the epidermis becomes detached. The caustic alkali also liberates ammonia from the mucilage around the germ.
Oily corn makes a dry kind of bread, and is not sufficiently adhesive to rise well without an admixture of rye, or other flour.
The oil of corn is easily convertible into animal fat by a slight change of composition, and consequently serves an excellent purpose for fattening poultry, cattle, and swine. Starch, also, is changed into fat as well as the carbonaceous substances of animals, and during its slow combustion in the circulation, gives out a portion of the heat of animal bodies; while, in its altered state, it goes to form a part of the living frame. Dextrine and sugar act in a similar manner, as a compound of carbon, hydrogen, and oxygen.
From the phosphates of grain, the substance of bone and the saline matters of the brain, nerves, and other solid and fluid parts of the body, are, in a great measure, derived.
The salts of iron go to the blood, and these constitute an essential portion of it, whereby it is enabled, by successive alterations of its degree of oxidation
