ORGANS OF MASTICATION. 313 



as being of great importance. It has been called the gan- 

 glial, from the nature of its apparent origin, and sympathetic, 

 from its functions, but more properly the great organic nerve. 

 It appears to arise from a small red ganglion or knot at the 

 base of the brain, and just previous to the commencement 

 of the spinal cord. It appears to have intimate communica- 

 tion with all the other nerves, and distributes branches to all 

 the glands, arteries, and absorbents of the system — the heart, 

 lungs, and digestive organs ; it is the soul, as it were, of the 

 organic system, influencing the functions of nutrition and se- 

 cretion. 



We have before observed that the brain of the sheep is 

 small as compared with the size of the body. In fact, the 

 whole nervous system is, as it were, feebly developed, and 

 this peculiarity has a considerable influence over the diseases 

 of the animal, and accounts for the fact that in the greater 

 number debility quickly supervenes, and in many the animal 

 speedily sinks. 



THE ORGANS OF MASTICATION, ETC. 



The mouth of the sheep and its contents are admirably 

 adapted for their natural functions. The sheep is intended 

 by Nature to thrive on scanty pasture and to take a consider- 

 able bite, and much closer to the ground than the ox. The 

 lips are therefore protected by hair, which defends them 

 from injury from the ground ; they approach somewhat to a 

 point, and the upper lip is cleft, which suits it well for the 

 purpose. 



The incisor teeth or nippers, like those of the ox, are sit- 

 uated only on the lower jaw, the upper having instead a firm 

 fibrous pad, sufficiently strong to retain the food between it 

 and the teeth. The incisor teeth are eight in number in a 

 perfect mouth, but the lamb, when dropped, has only two, 

 and sometimes none visible, but in a few weeks the others 

 make their appearance : these, however, are but temporary 

 teeth, smaller than the permanent ones, and adapted to the 

 size of the mouth. By two years old the central teeth drop 

 out, and are succeeded by two larger and stronger teeth — the 

 permanent. These teeth are formed within the sockets in 

 the bone some time previous to their appearance, and pressing 

 against the root of the temporary incisors, gradually induce 

 their absorption. By three years old the two next teeth 

 have undergone the same change, and are succeeded the 



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