47. _At five years old there is a full mouth of horse incisors, all the edges of which fairly meet._ The coloured engraving--which has been amply proved, by comparing it with the mouths of horses of various breed, among which those of blood have not been forgotten, since it was last tested by the aspect presented by the teeth of the well-known horse, The Baron,--will instruct the reader in the altered character which the mouth now assumes. It looks more huge, and far more powerful than it did at the fourth year. The teeth fairly close, but on inspection there can be detected slight signs of wear. The tables are not yet formed. The anterior edges alone are rendered level; all posterior to the infundibulum being as yet untouched. The tables then present the appearance indicated in the following wood-cut, which also represents the semi-circular order in which they are arranged. [Illustration] 48. _At five years off the corner teeth only show slight wear, and the posterior margins are round._ Much of the original coating of the crusta petrosa is retained, but in colour it may not at this time be dark. At those places where it has been recently worn down, it is often of a yellow tint, which is but a little deeper than the enamel, which last, however, is nevertheless easily distinguished by its greater transparency and more pearly appearance. This peculiarity in the crusta petrosa not unseldom gives to the six year old mouth a darker aspect than is presented by the teeth of the younger animal; and the author, to convey to the reader some idea of this fact, has purposely rendered the incisors of the next representation of the mouth, as they frequently are seen. Such a circumstance, however, will not confuse the judgment. The corner nippers still look young to him who is acquainted with those signs which denote youth in the horse's teeth, and the coloured engraving will convey a fair idea of the aspect they now put on. The corner nipper, in fact, after the fourth year, leads, in a great measure, if it does not entirely sway, the judgment. This tooth is sometimes called the shell tooth, on account of its infundibulum being, for the most part, better exhibited and longer retained than in the other incisors. The tables, however, of the other teeth should also receive some attention: those of the centre nippers may exhibit the infundibula shallow, or, in certain instances, when the crusta petrosa which lines these cavities is very thick, no infundibula may be distinguishable: even then, however, on close inspection, the form of the cavity will be discovered, marked out by a line of enamel, and the space that is usually vacant filled up with a substance, which in appearance differs little from the ivory. The tables of the lateral incisors will be fully formed, and the infundibulum is rarely obliterated, while its margin is always circumscribed and well defined, as the previous wood-cuts will indicate. [Illustration: _FIVE YEARS OFF._