THE FAMILY HORSE. 



teeth of the lower jaw which are usually examined to ascertain the 

 age. There are six of these. They are covered by a fine white 

 enamel enclosing the dentine or bony substance of the tooth. In 

 each permanent incisor, when it first appears, is a large cavity or 

 pouch, extending about one-third of the length from the crown. This 

 cavity is lined with enamel, and the lower pai't is filled with a dark ' 

 cement. The incisors or cutting teeth, when new, are oval near 

 the summit, and nearly triangular towards the roots. The teeth 

 of a horse usually wear down at the rate of about one-twelfth of an 

 inch a year. As this wear goes on, the exposed summits of the teeth 

 present different aspects from year to year. The accompanying 

 illustrations, after Thomas Brown, show these changes in the incisors 

 of the lower jaw. At three years old the two front milk teeth have 

 been replaced by permanent ones, with the peculiar hollow in the 

 summit called the *'mark." The canine teeth or "tushes," aa 

 horsemen call them, are just showing beneath the gum. At four 



-SEVEN TEARS. 



EIGHT TEAKS. 



years two more permanent teeth have come, the first two have 

 become somewhat worn, and the canine teeth are coming through 

 the gums. When the horse attains the age of five years, the per- 

 manent incisors are all in place; the two "corner teeth" show 

 the mark very distinctly, while it is entirely worn off from the two 

 middle incisors and partly off from the next two. At six years the 

 outer edges of the corner teeth are worn down, and the mark is 

 nearly obliterated from the two next ones. At seven years the 

 edges of the corner teeth are still more worn, the mark is nearly 

 gone from the middle of each, and the four front ones are worn 

 down entirely smooth. At eight years the mark has disappeared 

 from all the nippers. The dark spot in the center is a long oval, 

 lined with enamel, which comes near the front of the tooth . At ten 

 years the marks have worn entirely off the upper incisors, the dark 

 spot in the middle is smaller, and the four in front are less regularly 

 oval. At twelve years the enamel has nearly disappeared from the 

 central spot6 m the lower teeth, the four in front are somewhat 



