THE PROCESS OF TEETHING. 



199 



The breeder often attempts to hasten the appearance of the tush, and he cuts 

 deeply through the gum to remove the opposition which that would afford. 

 To a little extent he succeeds. He may possibly gain a few weeks, but not 

 more. After all, there is much uncertainty as to the appearance of the tush, 

 and it may vary from the fourth year to four years and six months. It belongs, 

 in the upper jaw, both to the inferior and superior maxillary bones (see n. 

 p. 110) ; for, while its fang is deeply imbedded in the inferior maxillary, the 

 tooth penetrates the process of the superior maxillary at the union of those bones. 

 At four years and a half, or between that and five, the last important change 

 takes place in the mouth of the horse. The corner nippers are shed, and the 

 permanent ones begin to appear. The central nippers are considerably worn, 

 and the next pair are commencing to show marks of usage. The tush has now 

 protruded, and is generally a full half- inch in height ; externally it has a rounded 

 prominence, with a groove on either side, and it is evidently hollowed within. 

 The reader needs not to be told that after the rising of the corner nipper the 

 animal changes its name the colt becomes a horse, and the filly a mare. 



At five years the horse's mouth is almost perfect. The corner nippers are 

 quite up, with the long deep mark irregular on the inside ; and the other 

 nippers bearing evident tokens of increasing 

 wearing. The tush is much grown the 

 grooves have almost or quite disappeared, 

 and the outer surface is regularly convex. 

 It is still as concave within, and with the 

 edge nearly as sharp, as it was six months 

 before. The sixth molar is quite up, and the 

 third molar is wanting. This last circum- 

 stance, if the general appearance of the 

 animal, and particularly his forehand and 

 the wearing of the centre nippers, and the 

 growth and shape of the tushes, are likewise 

 carefully attended to, will prevent deception, 

 if a late four-years-old is attempted to be substituted for a five. The nippers 

 may be brought up a few months before their time, and the tushes a few weeks, 

 but the grinder is with difficulty displaced. The three last grinders and the 

 tushes are never shed. 



At six years the mark on the central nippers is worn out. There will still 

 be a difference of colour in the centre of the tooth. The cement filling the 



hole, made by the dipping in of the 

 enamel, will present a browner hue 

 than the other part of the tooth, and 

 it will be evidently surrounded by an 

 edge of enamel, and there will even 

 remain a little depression in the centre, 

 and also a depression round the case 

 of enamel : but the deep hole in the 

 centre of the teeth, with the blackened 

 surface which it presents, and the 

 elevated edge of enamel, will have 

 disappeared. Persons not much accus- 

 tomed to horses have been puzzled 

 here. They expected to find a plain 

 surface of a uniform colour, and knew not what conclusion to draw when 

 there was both discolouration and irregularity. 



