1298. Thus the practical cultivator, who, notwithstanding Sir Humphry Davy's deductions from his experiments, continued to prefer using manure in a highly fermented state, so as to be what in practice is called short muck, is now fully justified by science. It is found, indeed, as practical men always asserted, that the decomposition of a dunghill does not throw off, in its first fermentation, any of the most valuable and the most efficient parts of the dung, but chiefly vapour of water; and that, though when the texture of the fibrous part of farm-yard manure begins to decompose, there will be an evolution of some of the gases which constitute the food of plants, no harm accrues to the dung as a manure from the escape of these gases. Sir Humphry Davy supposed that these gases constituted the food of plants, and that, if they were permitted to be dissipated by decomposition, the quantity of nourishment in the heap of manure would of course be so much diminished; that if the bulk of the dung-heap be diminished one half, or one third, by excessive fermentation, the quantity of nourishment to the crops would be diminished in a greater ratio; but practical men contended, that, though some of the gases which constitute the food of plants are disengaged from fermenting stable manure, yet that it does not follow that plants will receive them as food directly they are disengaged. On the contrary, it is considered that they would either reject food in that state; or, if they could not avoid taking it in, that they would be injured by it. 'Accordingly, we invariably find that plants suffer from their contact with fermenting dung, and it is this well-known fact, more than any other circumstance, which deters gardeners from applying dung in an unprepared state.' What has experience determined as the least injurious state in which dung can be applied to any crop ? The cultivator answers, in the state of short muck, that is, as 'a soft cohesive mass,' capable of being cut by a spade; and this is now proved by science to be the state in which it is best suited to afford plants their proper food.
