Sheep cannot be kept on the prairies without much care, artificial food, and proper attention; and losses have often occurred, by reason of a false system of economy attempted by many, from disease and mortality in the flocks, amply sufficient to have made a generous provision for the comfort and security of twice the number lost. More especially do they require proper food and attention after the first severe frosts set in, which wither and kill the natural grasses. By nibbling at the bog--the frostbitten, dead grass--they are inevitably subject to constipation, which a bountiful supply of roots, sulphur, etc., is alone sufficient to remove. Roots, grain, good hay, straw, corn-stalks, and pea or bean-vines are essential to the preservation of their health and thrift during the winter, everywhere north of thirty-nine degrees. In summer, the natural herbage is sufficient to sustain them in fine condition, till they shall have acquired a denser population of animals, when it will be found necessary to stock their meadows with the best varieties of artificial grasses. The prairies seem adapted to the usual varieties of sheep introduced into the United States; and of such are the flocks made up, according to the taste or judgment of the owners. Shepherd dogs are invaluable to the owners of flocks, in these unfenced, illimitable ranges, both as a defence against the small prairie wolves, which prowl around the sheep, but have been rapidly thinned off by the settlers, and also as assistants to the shepherds in driving and herding their flocks on the open ground. FALL FEEDING. In the North, the grass often gets very short by the tenth or fifteenth of November, and it has lost most of its nutritiousness from repeated freezing and thawing. At this time, although no snow may have fallen, it is best to give the sheep a light, daily foddering of bright hay, and a few oats in the bundle. Given thus for the ten or twelve days which precede the covering of the ground by snow, fodder pays for itself as well as at any other time during the year. It is well to feed oats in the bundle, or threshed oats, about a gill to the head, in the feeding-troughs, carried to the field for that purpose. WINTER FEEDING. The time for taking sheep from the pastures must depend on the state of the weather and food. Severe frosts destroy much of the nutriment in the grasses, and they soon after cease to afford adequate nourishment. Long exposure to cold storms, with such food to sustain them, will rapidly reduce the condition of these animals. The only safe rule is to transfer them to their winter-quarters the first day they cease to thrive abroad.