_Age of a Horse._—The age of a horse may be discovered by certain marks in the front teeth of the under jaw until he is eight years old, about which period they are generally worn out. An experienced person can, however, judge of a horse’s age pretty nearly by the countenance and general appearance of the animal, as well as by the length of the teeth and form of the tushes. Between the second and third year a colt begins to change his sucking or colt’s teeth, as they are termed, for permanent teeth, which are larger, and of a different form and colour. The sucking teeth are small, and of a delicate white colour. When a colt is three years old, or between the second and third year, he changes his two front teeth, above and below; between the third and fourth year the two next are changed; and between the fourth and fifth year the two next, or corner teeth, are changed. About the end of the fourth year, or a little later, the tushes appear. Mares have seldom any tushes. At five years old the horse has a full mouth of permanent or horse teeth, and the corner teeth are those by which the age is ascertained after that period: they have a remarkable hollow or shell-like appearance when they first come up; but by the time the horse has completed his fifth year they have acquired some size, and look more like the other teeth. There is a cavity on their upper surface, at this period, of a dark or blackish colour. At six years old the cavity is much diminished, and at seven it is still less; at eight it has entirely disappeared, or if any mark remain, it resembles rather the eye of a bean. The tushes at five years old have two concavities withinside them, converging upwards, and terminating in the point of the tooth: at six, one of these concavities is lost; that is, the one next the grinder: at seven, the other is diminished, but not quite gone: at eight, it is generally gone, but not always: afterwards the tush gradually gets more round and blunt. These are the changes by which the horse’s age is usually determined; but they are subject to variations, and the only certain method of ascertaining the age, after six, is by a reference to the breeder. The length of the teeth is no criterion whatever; nor can the countenance be depended upon until the horse becomes very old and grey. The marks in the upper teeth have been thought to indicate the age: the marks in the two front teeth disappearing at eight, in the two next at ten, and in the corner teeth at twelve. * * * * *