SATURAL HISTORY. 191 



&quot; That shrcp-cot, which in }&quot;ondcr vale you see 

 (Beset with groves, and those sweet springs hard by), 

 I rather would my palace wish to be 

 Than any roof of proudest majesty.&quot; DANIET&amp;gt;. 



laffering any injury. Few plants are more disrelished by cattle than the com 

 mon ragweed, and therefore the pastures on those lands in upland and humid 

 situations are very much infested by it ; but goats clear it off, if allowed to browse the 

 plants before they come into flower. There are many of the composite? which arc the 

 pests of our pastures, and which are, generally speaking, biennials, making roots the 

 first year, and bearing flowers the next, which might probably be cleared off by 

 pasturing with goats at proper times. The alternation with each other of animals, 

 one set of which can eat the plants that are disliked by another, is an important 

 point in the economy of our grazing districts, though it does not appear to hare 

 Tereived that attention to which it is entitled.* 



570. Why do sheep make a nodding motion of the head 



when feeding ? 



This motion is owing to the peculiar formation of the jaw 

 and the teeth. Sheep have no teeth in the upper jaw, but the 

 bars or the ridges of the palate thicken as they approach the fore 

 part of the mouth ; there is also the dense, fibrous, elastic matter 

 of which they are constructed, which becomes condensed, and 

 forms a cushion or bed that covers the convex extremity of the 

 upper jaw, and occupies the place of the upper incisor or cutting 

 teeth, and partly discharges their functions. The herbage is 

 firmly held between the front teeth in the lower jaw and this pad, 

 and is brought away by a half biting, half tearing action, which 

 occasions the peculiar motion of the head alluded to. 



571. The stalks of the common herbage of the field, bitten closely as they 

 are by sheep, are harder and more fibrous than the portions that are divided 

 and chopped by c itfle : and not only so, but some breeds of sheep are destined to 

 iive, iu 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 heath. The incisor teeth are evidently formed for browsing on these tough 

 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, pre 

 senting a convex surface oatwards, and a concaTe one within, forms a little scoop er 

 youge, capable of wonderful execution. He who will take the trouble to compare 

 the incisor teeth of cattle and of sheep both ruminants both by means of the 

 hall cutting and half tearing action, having the stomach, in which the process 



Partington s &quot; Cyclopjedia 



