The mode of rationing the Roman armies, and the manner in which the supplies were obtained and preserved, is well shown in the extant writings of those times. Besides the allowance of wheat daily,--one to two pounds,--the Roman soldiers often received a ration of pork, mutton, legumes, cheese, oil, salt, wine, and vinegar. With the grain, a porridge-pot, a spit, the casque for a cup, and with vinegar to mix with their water,--which formed the regulation drink posea, or acetum,--they marched rapidly, and retained their extraordinary vigor in the midst of pestilential regions. Every soldier carried his own food for a given length of time, which was from eight to twenty-eight days. "_Cibo cum suo._" Hence Josephus wrote, the Roman soldier is laden like a mule. This food was always of the best quality; and the wheat was always carefully selected by a commission appointed for the purpose, as we may learn from the inscription on the column of Trajan. This wheat was not always eaten raw; but was oftener roasted, and crushed upon a stone. "Frugesque receptas Et torrere parant flammis et frugere saxo." With all of these arrangements and movements, there was method even as to the time of taking food. The soldier ate twice a day, and at appointed hours--at the sixth hour, "Prandium;" and at the tenth hour, "Vesperna." X. The requirements of the system differ greatly, according to the degree of heat, the purity of the air, and the degree of physical exercise. What suffices at the equator would be but a morsel at the pole. What sustains the quiet student would starve the active athlete. When Volney spoke in surprise of the few ounces required to sustain the Bedouin, he forgot the purity of the air of the desert, as well as the indolent life of the Arab. When we offer as example the frugal diet of Cornaro, which was twelve ounces of solid food, with fourteen ounces of wine, daily, we must remember that the celebrated man lived a life of moderation, avoided bad air, and guarded against the extremes of heat and cold. The data of Frerichs, the observations of Sir John Sinclair, and the determinations of Professor Horsford, show that eighteen ounces of properly selected food may sustain life; and they also show that the nutrient substances must be of known value. XI. In forming our ideas as to the required amount of food necessary to healthy vigor, we will not attempt to analyze the magnitudes of Lehman, nor accept the statement of Chossat, that the animal body loses daily about one twenty-fourth of its weight by the metamorphosis of tissue; but will again examine the diet tables of the prisons, hospitals, and armies of Europe, leaving the reader to form his own conclusions.