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VETEKINAKY MEDICINE AND 8UEGEKY. 



quired ages to a form a perfect ideal series. For instance the mouth 

 represented in Fig. 160 (extreme age) obviously has belonged to a very 

 different animal to that shown in the preceding figure. Again Figs. 160 

 and 161 are fair specimens, though very diverse, of what may be expected 

 in extreme age in various cases. 



Bishop-ing. — Marks on the incisors are occasionally, though rarely, 



Fio. 149. 

 Double Mark at Seven Years. 



stimulated by means of caustic or the hot iron by low dealers with the 

 view of deceiving the unwary. 



The fraud is readily detected, because, though it is easy to make a black 

 mark on the crowns of the teeth, yet it is impossible to restore the wall 

 of pearly enamel, which, as explained above, surrounds the natural mark 

 or mfundibulum. Fig. 150. 



Fig. 150, 

 Real and Simulated Mark. 



The Fang-hole or Secondary Mark. — About nine years old, in con- 

 sequence of the wearing down of the teeth, a slight trace of the fang-hole 

 usually appears in the centre teeth, and somewhat later in the other teeth. 

 It is indicated by a slight discoloration of the tooth at the above point. 

 There is, however, no actual hole, because with advancing years the upper 

 part of the original cavity has become filled up with a sort of spuri- 

 ous dentine, which is more yellow than the true material, of which the 



