AGE, AS INDICATED BY THE TEETH. 423 



this will be clearly seen on reference to fig. 20. The teeth, though they 

 diminish in lateral breadth, increase in thickness from front to rear all 

 the way from the crown to the fang. (Figs. 20 and 21.) 



At six and up to eight years old, the teeth are all broad laterally at 

 their upper surfaces. (Figs. 6, 7, and 8.) Up to this time the exact 

 year, as the reader will recollect, is pretty well known by the " marks." 



At nine, when the marks fail, the alterations in the crown surface or 

 table come to our aid. The two centre teeth, which came up at three, 

 become somewhat triangular. (Fig. 9.) At ten, the two next teeth show 

 similar signs. (Fig. 10.) At eleven, the corner teeth have become some- 

 what triangular. (Fig. 11.) At twelve the triangularity has increased 

 in all the teeth. (Fig. 12.) This alteration continues to increase in all 

 the teeth, until in very old horses the depth from front to rear exceeds 

 the lateral width of the teeth. Figure 13 shows an average mouth of 

 sixteen years old. Figure 14 represents the appearance at twenty. Figure 

 15 shows twenty-four ; whilst figs. 16 and 17 may serve as specimens of 

 the teeth in extreme age. 



Length. Again, as age increases, the teeth, notwithstanding they really 

 wear down, become apparently longer. This effect is due to the fleshy 

 parts of the gums receding faster than the teeth wear down. In extreme 

 age, however, when the guns have receded as far as they can, the effect 

 of wear causes the teeth to become visibly as well as really shorter. 



Slope. An alteration also takes place in the position or " slope " of the 

 teeth, as regards their closing. This is due to the effect of wear. The 

 original form of the tooth is shown in fig. 21. Its upper portion, it will 

 be seen, is nearly perpendicular, whilst the lower part lies in a more 

 horizontal position. Hence in youth the teeth meet directly, whilst in 

 extreme age they can scarcely be said to meet at all. Their stumps 

 project forward in two almost parallel lines. (Figs. 26 and 27.) 



The various changes which take place in the position of the teeth in 

 reference to their position or " slope " are shown in figs. 2 to 27. At 

 two years old (fig. 2) the gums are full, fleshy, and prominent, and the 

 teeth are nearly perpendicular. The gradual changes, which take place 

 in the slope with increasing years, are shown perhaps more clearly in the 

 plates than could be explained in words. 



Up to twelve years old, there can scarcely be much difficulty in forming 

 a pretty correct judgment as to the age. After that time it requires 

 more time, practice, and opportunity than most people have at disposal 

 to obtain the requisite knowledge. 



It would probably scarcely interest the non-professional reader to trace 

 very minutely the changes which take place after twelve years old. 

 Suffice it to say, that the gums continue year by year to recede, the teeth 

 become apparently longer and longer and really narrower, and conse- 

 quently the intervals between them increase, and they project forward 

 more and more in a straight line. 



About twenty or twenty-two, and in some instances a good deal sooner, 

 the teeth, which up to this period have apparently increased in length, 

 begin to grow visibly shorter, because the gums are so far absorbed that 



