153 



A bit of stone, a piece of iron, or a nail may have got into the corn, 

 and caused the injury. By removing the loose portion of the tooth, 

 the animal generally does well, but, in time, the tooth opposite becomes 

 elongated, owing to its not meeting sufficient wearing surface, and has 

 to be cut off, or dressed down with a tooth rasp. 



355. It is said by some writers that teeth grow ; to a certain extent 

 this is true, but at six years old all the teeth are fully developed, after 

 which period they gradually wear away. This is well exemplified by 

 the incisors, or nippers, becoming triangular as they wear down, when 

 their crowns take the shape of the fang or root. Teeth, however, 

 become elongated when they are not made use of, owing to the tooth 

 opposite being decayed or removed. As a proof that they wear, and 

 do not grow, see Plate XXVIII., Nos. 1 and 2, which shows the upper 

 molar of a six-year-old horse, and one of a horse twenty- six years of 

 age. Damaged teeth are, however, most likely to become carious. I 

 have come across a few of this nature, but, in young animals, as 

 already stated, I think the disease more frequently commences in the 

 alveolar processes (bone plates), and sinuses ; finally implicating the teeth 

 themselves. Disease of the teeth of the horse is not very common, 

 but when a diseased tooth is present, the animal generally quids its 

 food, i.e. chews it, and then lets it drop out of the mouth in small 

 pellets ; in such cases the tooth has to be removed. 



356. With the forceps I have had made (Plate XXX., No. 3.), and 

 which I find to be an improvement upon Professor Pritchard's, by the 

 addition of the screw, and longer leverage, I can, in a few minutes, 

 remove any molar, either from the upper or the lower jaw. In 

 extracting a tooth, I have the animal cast, but have a great objection 

 to casting aged horses with "hobbles." I prefer side lines in these 

 latter cases. I do not use chloroform, unless specially requested to do 

 so, as I think it is not necessary. After removing the tooth, I always 

 dress the hole every third day, by plugging with tow, saturated with 

 three parts water and one part tincture of iron, which answers 

 splendidly, finally filling it with gutta-percha. In one case, the diseased 

 bone was so great, extending through into the nostril, that it took four 



