These are the most profitable of all domestic animals. The original cost is trifling, and the expense of raising and keeping is so light, and the sale of meat, tallow, hide, and wool, is so ready, that sheep-growing is always profitable. So important has this always been considered, that in all ages of the world, there have been shepherds, whose sole business it has been to tend their flocks. Were the flesh of sheep and lambs more extensively substituted for that of swine, in this country, it would be equally healthy and economical. American farmers do not attach to sheep-growing half the importance it deserves. We recommend a thorough study of the subject, in the use of the facilities afforded by the writings of practical men. We can only give the outlines of the subject in a work like this. A theory has been scientifically established by Peter A. Brown LL. D. of Philadelphia, in which it is shown that all sheep are divided into two species, Hair-bearing and Wool-bearing. These species crossed, produce sheep that bear both wool and hair, as the two never change. The hair makes blankets that will not shrink. The wool is good for making fulled cloth. Blankets made from the fleeces of sheep that are the product of the cross of these two species, will shrink in some places and not in others, just as the hair or wool prevails. It is also true that the hair-bearing sheep delight in low, moist situations and sea-breezes, while the wool-bearing sheep does best on high, airy, and dry land. These fleeces all pass as wool, but the microscope shows a marked and permanent difference, and one can easily learn to distinguish it at once, by the touch and with the naked eye. This is thrown out here to induce a thorough examination of the whole subject. There are three staples of wool, short, three inches long, middling, five inches, and long, eight inches. Varieties of sheep are numerous. We shall only mention a few. The question of the best breeds has been warmly controverted. We have no disposition to try to settle it. The question of the best variety must depend upon locality and design. If the wool is the object, then the Vermont Merino for the North, and the pure Saxony for the South, are evidently the best. If located near large cities, where the flesh is the main object, then the large-bodied, long-wooled breeds are much preferable. Among those much esteemed we note the following:--