THE TEETH. 3
and decomposition is accompanied by the presence or development of an acescent principle. It has been stated that an elastic pad occupies the place of teeth in the upper jaw; and that it is by a half biting and half tearing action that the sheep gathers his food: the necessary consequence is, that some of the grass, of harder construction than the rest, does not give way, but is torn up by the roots; a portion of the mould adheres to the roots, and is swallowed, and, all our soils containing more or less absorbent or calcareous earth, the acid is neutralized, and, as it were, removed, as rapidly as it is formed; except in some extreme cases, attributable almost entirely to the neglect or thoughtlessness of the proprietor of the sheep.
The teeth of the sheep are the same in number as in the mouth of the ox. There are eight incisor or cutting teeth in the fore part of the lower jaw, and six molars in each jaw above and below, and on either side. The incisors are more admirably formed for the purpose of grazing than in the ox. The sheep bites closer than the ox; he was destined to live where the other would starve: he was designed in many places to follow the other, and to gather sufficient nourishment where the" ox would be unable to crop a single blade. Two purposes are answered by this: all the nutriment that the land produces is gathered from it, and the pasture is made to produce more herbage than by any other means it could be forced to do. The sheep by his close bite not only loosens the roots of the grass, and disposes them to spread, but by cutting off the short suckers and sproutings, —a wise provision of nature— causes the plant to throw out fresh, and more numerous, and stronger ones, and thus improves and increases the value of the crop. Nothing will more expeditiously or effectually make a thick permanent pasture than its being occasionally and closely eaten down by sheep.
In order to enable the sheep to bite thus close, the upper lip is deeply divided, and free from hair about the centre of it.
The stalks of the common herbage of the field, bitten thus closely as they are by the sheep, are harder and more fibrous than the portions that are divided and cropped by cattle; and not only so, but some breeds of sheep are destined to live, in part at least, on harder food than falls to the lot of cattle, as the different kinds of heath, or substances almost as difficult to be broken off as the branches of the heath. The incisor teeth are evidently formed for browsing on these dense productions of the soil, which would otherwise be altogether useless and lost. The part of the tooth above the gum is not only, as in other animals, covered with enamel to enable it to bear and to preserve a sharpened edge, but the enamel on the upper part rises from the bone of the tooth nearly a quarter of an inch, and, presenting a convex surface outwards, and a concave one within, forms a little scoop or gouge capable of wonderful execution. He who will take the trouble to compare together the incisor teeth of cattle and of sheep—both ruminants—both by means of the half-cutting and half-tearing action having the stomach, in which the process of maceration is going forward, abundantly supplied with absorbent or alkaline earth—the one, however, destined to crop little more than the summit of the grass, and the other to go almost close to the roots, and occasionally to browse on harder food — will have a not uninteresting illustration of the manner in which every part of every animal is adapted to the situation in which he is placed, and the destiny he is to fulfil. The pad also is firmer and denser than in cattle, yet sufficiently elastic, so that it is in no danger of injury from the sharp chisels below, while the interposed substance is cut through with the greatest ease.B2
