Page:Notes on the State of Virginia (1853).djvu/196

180 the evil will be cured by cold. A degree of heat, beyond that which hatches the egg, we know will kill it. But in aiming at this we easily run into that which produces putrefaction. To produce putrefaction, however, three agents are requisite: heat, moisture, and the external air. If the absence of any one of these be secured, the other two may safely be admitted. Heat is the one we want. Moisture then, or external air, must be excluded. The former has been done by exposing the grain in kilns to the action of fire, which produces heat, and extracts moisture at the same time; the latter, by putting the grain into hogsheads, covering it with a coat of lime, and heading it up. In this situation its bulk produces a heat sufficient to kill the egg; the moisture is suffered to remain indeed, but the external air is excluded. A nicer operation yet has been attempted: that is, to produce an intermediate temperature of heat between that which kills the egg, and that which produces putrefaction. The threshing the grain as soon as it is cut, and laying it in its chaff, in large heaps, has been found very nearly to hit this temperature, though not perfectly, nor always. The heap generates heat sufficient to kill most of the eggs, whilst the chaff commonly restrains it from rising into putrefaction. But all these methods abridge too much the quantity which the farmer can manage, and enable other countries to undersell him, which are not infested with this insect. There is still a desideratum then to give with us decisive triumph to this branch of agriculture over that of tobacco. The culture of wheat, by enlarging our pasture, will render the Arabian horse an article of very considerable profit. Experience has shewn that ours is the particular climate of America, where he may be raised without degeneracy. Southwardly the heat of the sun occasions a deficiency of pasture, and northwardly the Winters are too cold for the short and fine hair, the particular sensibility and constitution of that race. Animals, transplanted into unfriendly climates, either change their nature and acquire new fences against the new difficulties in which they are placed, or they multiply poorly and become extinct.