DISEASES AND TREATMENT OF THE HORSE 327 
At five he sheds the four corner, or outside teeth, and 
gets permanent ones. So, at this age, the horse has a full 
mouth of permanent front teeth. 
At five years of age each of the front teeth contains a 
black ring. 
At six the rings on the ^wo centre teeth of the bottom 
row disappear, a black spot only being left in its place. 
At seven the rings on the laterals (teeth next to the 
centre pair in the lower row) disappear and a black spot 
only is left on each. 
At eight the rings on the corner teeth of the lower row 
disappear and a black spot only is left on each. 
At nine the rings on the two centre front teeth of the 
upper row disappear, a black spot remaining on each. 
At ten the rings on the laterals (those next to the centre 
pair in the upper row) disappear, a black spot only remaining. 
At eleven the rings on the corner teeth of the upper jaw 
disappear, a black spot remaining in place of each ring. 
At twelve the change again takes place in the lower jaw. 
The two centre teeth become much narrower and longer than 
the others. 
At thirteen the laterals (those next to the centre opair — 
one on each side"* become much longer and narrower. 
At fourteen the same change takes place in the lower 
corner teeth. 
At fifteen this change appears in the two centre teeth of 
the uppers — they, too, becoming much longer and narrower. 
At sixteen the upper laterals are similarly affected. 
At seventeen the long, narrow effect is produced in the 
corner teeth of the upper row. 
At eighteen the change again shifts to the lower row, the 
two centre ^^eeth becoming much shorter. 
At nineteen this short effect is produced in the laterals of 
the same row. 
At twenty the lower corner teeth are much shorter. 
At twenty-one the change is again produced in the 
uppers. The two centre teeth become much shorter. 
At twenty-two the upper laterals become shorter. 
At twenty-three the upper corner teeth become shorter. 
After the horse has attained the age of twenty-four or 
over his age cannot be determined with any degree of accur- 
acy by the appearance of his teeth. 
