142 i I.TERINART DENTAL SURGERY. 



beyond the teeth on either side of it, owing to the 

 loss of the corresponding tooth of the lower jaw. 

 There can be no doubt that it was the direct cause of 

 the animal's death, it having cut deep into the lower 

 jaw, and even worn away a considerable portion 

 (three-quarters of an inch) of bone. 



If we examine the cut closely we will notice that 

 the roots do not extend within three-quarters of an 

 inch as far up into the alveolar cavity as those of the 

 teeth on either side. Taking the difference of 

 measurements of the projecting tooth and those on 

 either side, and we have one-fourth inch more on 

 the crown of the projecting tooth than would other- 

 wise have been there had the tooth constantly 

 remained in wear.* 



The drawing for the above cut was made from 

 one of many specimens that I have in my possession, 

 all of which are deemed as convincing proofs that 

 the teeth do not continue to grow during life. 



It is difficult to determine the exact time at which 

 the tooth ceases to grow. I have endeavored to col- 

 lect the opinions of some of the best veterinary 

 anatomists in this country, and for this purpose the 

 following questions were sent out: 



First How long are the permanent teeth of the 

 horse in developing? 



* The fact that the roots of the fourth molars are always shorter than 

 those of the third and fifth must not be lost sight of in making a com- 

 parison. The difference amounts to from one- fourth to five-sixteenths of an 

 inch, as shown in Fig. 32, which was drawn from a perfectly healthy mouth. 



