148 ANATOMY AND DISEASES OF THE NOSE AND MOUTH. 



tower jaw than in the upper, but this distance increasing in both jaws with the ag 

 of the animal. In shape it somewhat resembles a cone ; it protrudes about an inch 

 from the gum, and has its extremity sharp-pointed and curved. At the age now undei 

 eonsideration, the tushes are almost peculiar to the horse, and castration does nof 

 appear to prevei.t or retard their development. All mares, however, have the germs 

 of them in the chambers of the jaw, and they appear externally in the majority of ola 

 mares. Their use is not evident. Perhaps in the wild state of the animal they are 

 weapons of offence, and he is enabled by them more firmly to seize, and moro deeply 

 wound his enemy. 



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 exten 

 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. 70) ; for, while its fang is deeply imbedded 

 n the inferior maxillary, the tooth penetrates the process of the superior maxillary at 

 lie 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 gene- 

 rally 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 

 8. horse, and flu 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 circumstance, if the general appearance 

 of the animal, and particularly his forehead and 

 the wearing of the centre nippers, and the growth 

 and shape of the tushes, are likewise carefully 



\ <^2%Z/t' (\ $n Bended 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 month* 

 before their time, and the tushes a few weeks, but the grinder is with difficulty dis- 

 placed. The three last grinders and the tushes are never shed. 



At six years the mark on the central nip- 

 pers ia worn out. There will still be a differ- 

 ence 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 cen- 

 tre of the teeth, with the blackened surfac* 

 which it presents, and the elevated edge of 

 enamel, will have disappeared. Persons not 

 much accustomed to horses have been puzzled 

 here. They expected to find a p*ain surface 

 of a uniform colour, and knew n< ( what con- 

 elusion to draw when there was both discolouration and irregularity. 



