AND METHOD OF JUDGING THE AGE. 



379 



Hterated, and the infiindibulum is then only surrounded by a 

 mass of ivory, much thicker anteriorly than posteriorly. * 



Before that of five years old, the age of the horse is ascertained 

 by the presence or disappearance of the temporary teeth ; and 

 from five to eight by the disappearance of the mark ^Yhich is 



» 



TTiis plate exhibits the lower incisors at 

 tenial structure of a yowng permanent 

 sinular tooth. 



Fig. 1, Soon after biitli. 

 2, One year off. 

 .3, Rising three yearE. 



4, Four and a lialf years old. 



5, Five years old. 



6, Six years old. 



7, Seven years old. 



8, Eight years old. 



9, Twelve years old. 



10, About fourteen years old. 



11, About sixteen years old. 



eleven different periods of life ; also the in- 

 incisor, tvith several transverse sections of a 



1 2, A young horse's incisor tooth, 

 with an opening made at the 

 middle, exposing to view the 

 lower ))ortion of the funnel a. 



1,T, Exhibits five transverse sections 

 of a young incisor tooth, the 

 three first portions a, b, c, having 

 the funnel ; the variation in the 

 shape of each surface is worthy 

 of notice, tlie oval gradually 

 becoming trianirular. 



The face of a tooth just cut presents a sharp edge surrounding the cavity or 

 mark : this edge is entirely covered Avith enamel, which, however, soon gets 

 worn off, and thus the internal enamel becomes separated from the external. 

 * The (lid touth is therefore considerably heavier than the young tooth ; 

 and from the length of time the centre enamel remains after the disappear- 

 ance of the mark, it appears that the old solid tooth wears much more slowly 

 than the young hollow tooth. 



