THE TEETH. 



137 



strong one, constituting the cheek of the horse arising from the superior 

 maxillary under the ridge continued from the zygomatic arch, and inserted 

 into the lower jaw, and particularly round the rough border at the angle 

 of the jaw. This acts with the temporal muscle in closing the jaw, and 

 in giving the direct cutting or champing motion of it. 



Inside the lower jaw, on each side, and occupying the whole of the 

 hollowed portion of them, and opposite to the masseters, are the pterygoid 

 muscles, going from the jaws to bones more in the centre of the channel, 

 likewise shutting the mouth, and also, by their alternate action, giving that 

 grinding motion which we have described. 



The space between the branches of the lower jaw, called the channel, is 

 of considerable consequence. It may be a little too wide, and then the 

 face may have a clumsy appearance; but if it be too narrow, the horse 

 will never be able to bend his head freely and gracefully ; he will be always 

 pulling and boring upon the hand, nor can he possibly be well reined in. 



The jaws contain the teeth, which are the millstones employed in this 

 operation. The mouth of the horse at five years old contains forty teeth, 

 viz. six nippers or cutting teeth in front, a tush on each side, and six 

 molars, or grinding teeth, above and below ; they are contained in cavities 

 in the upper and lower jaws, surrounded by bony partitions, to which they 

 are accurately fitted, and by which they are firmly supported. For a Uttle 

 way above these bony cavities, they are surrounded by a hard substance 

 called the gum, so dense, indeed, and adhering so closely to the teeth and 

 the jaws, as not to be separated without very great difficulty ; singularly 

 compact, that it may not be wounded by the hard or sharp particles of the 

 food, and almost devoid of feeling, for the same purpose. 



Seven or eight months before the foal is born, the germs or beginnings 

 of the teeth are visible in the cavities of the jaws. The tooth grows, and 

 presses to the surface of the gum, and forces its way through it ; and at 

 the time of birth the first and second grinders have ap- 

 peared, large compared with the size of the jaw, and 

 seemingly filling it. In the course of seven or eight 

 days the two centre nippers are seen as here repre- 

 sented. 



They likewise appear to be large, and to fill the front 

 of the mouth, although they will afterwards be found to 

 be small, compared with the permanent teeth that follow. 

 In the course of the first month the third grinder ap- 

 pears above and below, and not long after, and generally 

 before six weeks have expired, another incisor above and 

 below will be seen on each side of the two first, which 

 have now considerably grown, but not attained their 

 perfect height. This cut will then represent the ap- 

 pearance of the mouth. 



At two months, the centre nippers will have 

 reached their natural level, and between the second 

 and third month the second pair will have over- 

 taken them. They will then begin to wear a little, 

 and the outer edge, which was at first somewhat 

 raised and sharp, is brought to a level with the inner 

 edge, and so the mouth continues until some time 

 between the sixth and ninth month, when another 

 nipper begins to appear on each side of the two first, 

 making six above and below, and completing the colCs 



