THE STRUCTURE OF THE TEETH 63 



less degree, or the absence of "the mark in the mouth." 

 The ivory in the molars will be found generally nearly on 

 a level with cutting ridges of enamel, in spite of the 

 greater attrition which the substance forming the larger 

 portion of the surface of the table must receive. There 

 is, however, sufficient projection of the enamel ridges to 

 enable you to feel that the latter material is the great 

 resisting power, and saves the destruction of the ivory by 

 the grinding wear, to which, but for such support, it would 

 be inevitably exposed. 



At Birth. — Many months — at least, seven — before the foal 

 is produced the germs of the teeth are visible in the 

 cavities of the jaws of the foetus, as small bags of jelly-like 

 consistence. As these grow they harden and press towards 

 the surface of the gum, forcing their way through it ; so 

 that, about the time of birth, three of the grinding teeth 

 are discoverable in each jaw ; and generally two front cut- 

 ting teeth, in the colt called nippers, which are placed 

 almost laterally (see figure), and are remarkably large in 

 comparison with the size of the animal. In a less 

 developed colt the nippers will present themselves as in 

 our drawing, at the end of a week or nine days. In the 

 next two months, two more cutting teeth in each jaw, 

 above and below, will bring the number up to eight. And 

 now the jaws having widened, as is seen more fully in our 

 second figure (six to seven months), the two nippers, which 

 filled all the forepart of the narrow jaw, will have taken 

 their proper places in front of the mouth. They will now 

 begin to wear a little, and the outer edge, which was 

 raised and sharp, will be brought on a level with the inner 

 edge. The mouth, too, will alter little now until it forms 

 as in our second figure, when yet two more nippers begin 

 to be felt, and then seen, making up six below, and a like 

 number above — thus filling up the " colt's mouth,'' as 

 shown in the third drawing, inside and outside being 

 figured. The name of " nipper " is peculiarly applicable to 

 the front teeth of a colt's mouth. Those of incisor or 

 cutter, adopted by professionals and anatomists, do not so 

 well convey the idea of their action. The twitch of the 

 head in the act of browsing or grazing is rather the act of 

 " nipping," and partly snatching, than merely cutting off. 



It may be noted at the seventh or eighth month, that 

 though the corner milk-teeth are up, their edges do not 



