In like manner the leguminous seeds, and farinaceous roots are greatly altered by the chemical action of heat. The raw potatoe is ill-flavoured, extremely indigestible, and even unwholesome. By roasting, or boiling, it becomes farinaceous, sweet, and agreeable to the taste, wholesome, digestible, and highly nutritious. Little is lost, and nothing is added to the potatoe by this process, yet its properties are greatly changed; its principles, in short, have suffered very remarkable chemical changes. Even in the simple boiling of the various leguminous seeds, pot-herbs, and esculent roots, the effect does not seem confined to the mere softening of the fibres, the solution of some, and coagulation of other of their juices and principles; not only their texture, but their flavour, and other sensible qualities have undergone a change, by which their alimentary properties have been improved; the farinaceous matter by boiling is rendered soluble, the vegetable fibre softened. Saccharine matter is often formed, mucilage and jelly extracted and combined, and the product is rendered more palatable, wholesome, and nourishing. And, although every country has its own favourite articles of food, and modes of preparing them, and there is perhaps no subject in regard to which local prejudices are so strong, yet there can be no reason why the farinaceous matter of cereal seeds should always be consumed in the state of bread; many of them are not less agreeable, and not less wholesome in other forms of food. In Scotland nine-tenths of those in the more humble walks of life live upon barleybroth, and there are not more healthy people to be found any where.—_Cullen’s Materia Medica_, v. I. p. 287. It is chiefly to save the trouble of dressing any other kind of food, and that bread, from its portability and convenience of always being ready, has become the principal sustenance, but it is far from being the most economical method of using farinaceous grain. There can be no doubt that the same quantity of farinaceous matter made into bread might, in other forms, be used to a much greater advantage; for the great art of preparing good and wholesome food is to convert the alimentary matter into such a substance as to fill up the stomach and alimentary canal without overcharging it with more nutritive matter than is requisite for the support of the animal, and this may be done either by bread, or by converting the mealy substance of which it is composed into other forms, of which there is a great variety.