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. The process is slow, and in the action some of the natural sweetness of the flour is lost. In what is known as aërated bread, the gas made was forced directly into the dough, by means of a machine invented for the purpose; and a very scientific and very good bread it is. But it demands an apparatus not to be had save at great expense, and the older fashions give a sufficiently sweet and desirable bread. _Rye_ and _Indian Corn_ form the next best-known varieties of flour in bread-making; but barley and oats are also used, and beans, pease, rice, chestnuts, in short, any farinaceous seed, or legume rich in starch, can fill the office. _Oatmeal_ may take rank as one of the best and most digestible forms of farinaceous food. Some twenty-eight per cent of the grain is husk, seventy-two being kernel; and this kernel forms a meal containing twelve parts of nitrogenous matter, sixty-three of carbo-hydrates, five and a half of fatty matter, three of saline, and fifteen of water. So little gluten is found, that the flour of oats can not be made into loaves of bread; although, mixed and baked as thin cakes, it forms a large part of the Scotchman's food. It requires thorough cooking, and is then slightly laxative and very easily digested. _Buckwheat_ is very rich in nitrogenous substances, and as we eat it, in the form of cakes with butter and sirup, so heating a food, as to be only suitable for hard workers in cold weather. Indian corn has also a very small proportion of gluten, and thus makes a bread which crumbles too readily. But it is the favorite form of bread, not only for South and West in our own country, but in Spanish America, Southern Europe, Germany, and Ireland. It contains a larger amount of fatty matter than any other grain, this making it a necessity in fattening animals. In a hundred parts are eleven of nitrogen, sixty-five of carbo-hydrates, eight of fatty matter, one and a half of saline, and fourteen of water. The large amount of fatty matter makes it difficult to keep much meal on hand, as it grows rancid and breeds worms; and it is best that it should be ground in small quantities as required.