It is by this difference, then, that the ox chews the cud, and that the horse cannot perform this operation. But there is still another difference in the horse, which hinders him from chewing the cud, and is the reason why he cannot vomit; the passage of the oesophagus being placed obliquely in the stomach, the membranes of which are very thick, makes a kind of gutter in them so oblique that it must close still more instead of opening by the convulsive motions of the stomach. Although this difference, as well as many others we observe in the conformation of the bodies of these animals, depend on their constant nature, nevertheless, there are in the development, more particularly in the soft parts, differences constantly in appearance, but which may, and actually do, vary from circumstances. The vast capaciousness of the ox's paunch, for example, is not entirely owing to Nature; it is not of that size in its primitive conformation, but attains it by degrees, from the large quantity of aliment it receives; for, in the calf, which is not very young, but has eat no grass, the paunch is much smaller in proportion than in the ox. This capaciousness of the paunch proceeds, then, from the extension which is occasioned by the large quantity of aliments, of which I was well convinced by an experiment that appeared to me decisive. I brought up two lambs of the same age, one on bread, the other on grass, and when they were a year old, on opening them, I found the paunch of the lamb which had lived on grass was much larger than that which had lived on bread. It is said that _oxen_ which eat slowly are more capable of working than those which eat quick; that _oxen_ fed on high and dry lands are more lively, vigorous, and healthy, than those which live on low and humid grounds; that they are all stronger when fed on dry hay than when fed with grass; that they meet with more difficulty on the change of climate than horses, and that, for this reason, _oxen_ for the plough should never be purchased but in their own neighbourhood. In winter, as _oxen_ do nothing[F], it is sufficient to feed them on straw, with a little hay; but at the season they work they should have more hay than straw, likewise a little bran, or a few oats. If hay is scarce they should have fresh-cut grass, leaves of ash, elm, oak, &c. but this food should be given in a small quantity, because the excess of it, being what they are very fond of, occasion them to avoid bloody urine; but lucerne, saintfoine, lupins, turnips, boiled barley, &c. are very good for them, and as they never eat more than is necessary, they should always be supplied with as much as they will take. They should not be put to pasture till about the middle of May; they should be kept at pasture all the summer; and, about the middle of October they should be brought back to fodder, only observing not to change them too suddenly from green to dry food, or from dry to green, but to bring them to it by degrees.