IRREGULARITIES FROM CRIBBING. 147 



has been taken, the animal makes an effort of deglutition, which 

 is followed by a pecuhar " cluck " sound. In examining an 

 animal, even where the age is readily recognized, care should 

 be taken to open the jaws completely, so as to inspect all sur- 

 faces of the teeth. While cribbing marks, when on the anterior 

 face of the teeth, are apparent on superficial examination, those 

 on the posterior face are often hidden by the foam and saliva, 

 unless care is taken to wipe the latter away. A slight bevel 

 worn on the anterior surface is evident, with the teeth closed, 

 from the separation of the enamel and the presence of a yellow 

 line, made by the exposed dentine, while a considerable bevel 

 might be overlooked when its surface is a continuation of the 

 yellow dentine of the table and is looked at from in front. 



It is often of the greatest importance to determine if the 

 irregular areas of use on a horse's teeth are due to accident, or 

 are the result of cribbing. Undoubtedly, some cases of cribbing 

 find their origin in the bad habit of cleaning a horse in its stall, 

 where it can bite at and seize the manger, etc. In these cases 

 the edges of the teeth are rough and jagged, and it is only after 

 the habit becomes confirmed that the worn parts become smooth 

 and polished and evenly used in their irregularities. In other 

 cases, where attempts have been made to cure the horse of the 

 habit, by fastening it so that it cannot reach the object on which 

 it cribs, it changes its mode of cribbing and may wear various 

 parts of the incisors, and then the teeth, losing the support of the 

 enamal in front and behind, become very irregular and broken. 



When the animal cribs by pressing the incisors against 

 some foreign body, the wearing takes place on the anterior face 

 of the teeth (Fig. 153, a, b, c, d). 



When the object is seized in the mouth it may wear only 

 the posterior faces (Fig. 154, A, b, c); or, if a thin board or 

 similar body is held, it may wear the anterior borders of one 

 jaw and the posterior of the other (Fig. 154, d, and Fig. 155, a). 



If a thin object is seized evenly between the jaws, the 

 tables of the upper or the lower or of both sets of incisors may 

 be worn. In the latter case the age must be determined by the 



