40 OF THE TEETH. 



variation, yet the veterinarian would do well to accustom 

 himself to an examination of the tushes, as it occasionally 

 happens that he can only take a very hasty glance at the 

 mouth of some animals ; but there are few that will not 

 allow the finger to be passed between the lips. In the 

 evening also, or in very dark stables, the tush will often 

 afford a useful, though not a positive indication as to the 

 sex of the animal, mares generally having no tushes. 



Making the nippers our principal guides, we proceed to 

 remark that, during the period between the fifth and sixth 

 years, the cavity in the front nippers wears away; and thus 

 a horse is said to have lost his mark at six. The close 

 observer will, however, yet be able to discover a central 

 discoloured depression, and a prominent ridge of enamel 

 around it, with an intervening part occupied by what has 

 been already called the bone of the tooth. 



At seven, similar appearances have taken place in the 

 middle nippers, which have now lost their mark also. 



At eight, the mark, or rather the cavity, is obliterated 

 from the corner teeth likewise, and in jockey language the 

 horse is now aged. 



The marks, however, are very uncertain guides, being 

 subject to numerous variations, hardly ever alike and never 

 to be absolutely trusted. The mouth, indeed, ceases to be 

 a certain guide after the fifth year, though the age may be 

 told with tolerable accuracy up to the sixth year, when all 

 the teeth are fully up or close together. 



It must, however, never be lost sight of, that the de- 

 scriptions which have been given of dentition throughout 

 are best understood, — indeed, can only be justly appre- 

 hended, by considering that it is not by simple wearing 

 away of the upper surface, and consequent decrease of 

 the column of the tooth, that the indicatory changes 

 in their appearances take place, particularly in the pro- 

 tracted periods of life, but by a disposition in the teeth to 

 shoot upwards to meet the continual deterioration going 

 on ; by which a gradual exposure of their under surfaces is 

 made far heloiv the original depth of the central cavity pro- 

 ducing the ynarh. It must, also, not be forgotten, that as, 

 on a view of the figure of a tooth throughout its whole 

 extent, the fang will be found to vary much from the free 



