In seeds, when fully ripe, little sugar or gum is generally present, and it is chiefly by the amount of starch and gluten they contain, that their nutritive power is to be estimated. In bulbs, such as the turnip and potato, sugar and gum are almost always present in considerable quantity in the state in which these roots are consumed, and this is especially the case with the turnip. These substances, therefore, must be included among the nutritive ingredients of such kinds of food. If we suppose an acre of land to yield the following quantities of the usually cultivated crops, namely— Of wheat, 25 bushels, or 1500 lbs. Of barley, 38 ” or 2000 ” Of oats, 50 ” or 2250 ” Of peas, 15 ” or 1000 ” Of beans, 25 ” or 1600 ” Of Indian corn, 60 ” or 3120 ” Of potatoes, 10 tons, or 22400 ” Of turnips, 25 ” or 56000 ” The weight of dry starch, gluten, sugar, and gum, reaped in each crop, will be represented very nearly by the following numbers:— Starch. Gluten and Sugar and Woody Albumen. Gum. Fibre. Wheat, 825 lbs. 315 lbs. 60 — Barley, 1200 ” 120 ” 160 — Oats, 1215 ” 100 ” 250 — Peas, 420 ” 260 ” 20 — Beans, 670 ” 370 ” — — Indian corn, 2100 ” 280 ” 90 — Potatoes, 2688 ” 224 ” — 1253 Turnips, 3090 ” 1400 ” 5000 — If it be granted that the crops above stated are fair average returns from the same quality of land—that the acre, for example, which produces 25 bushels of wheat, will also produce 10 tons of potatoes, and so on—then it appears that the land which, by cropping with wheat, would yield a given weight of _starch_, would, when cropped with barley or oats, yield one-half more, with Indian corn or potatoes about three times as much, and with turnips five times the same quantity. In other words, the piece of ground which, when sown with wheat, will maintain one man, would support one and a half if sown with barley or oats, three with Indian corn or potatoes, and five with _turnips_—_in so far as the nutritive power of these crops depends upon the starch and sugar they contain_. Again, if we compare the relative quantities of gluten, we see that wheat, beans, and Indian corn yield, from the same breadth of land, nearly an equal quantity of this kind of nourishment—potatoes one-third less, and barley and oats only one-third of the quantity—while turnips yield four times as much as either wheat, beans, or Indian corn.