Such are the different aspects which the face of the tooth assumes in the course of the three years following its eruption from the jaw; and it must be evident to our reader, from what has been said heretofore, that the different teeth must undergo these alterations during different years of the ani mal's life. For example, the front teeth, being cut on the third year, will assume them successively on the 4th, 5th, and 6th; the middle teeth, on the 5th, 6th, and 7th, in consequence of not being cut until the year after the former; and the corner teeth, on the 6th, 7th, and 8th years. On the completion of the 9th year, the white rims are hardly visible, the pits are all filled up, and the marks nearly or quite obliterated. At least, such is the general course of these changes; as will be seen by a reference to the Figs. 5, 6, 7, 8, 9, 10, in Plate DXXXII.
Some horses preserve the beans or marks for a very long period; occasionally, even through life: nevertheless, the pits arc completely filled up, and the face is in every respect perfect.
Concerning the dental indications of age after the 9th year, we cannot do better than present our reader with an extract from Lafosse's work on Ve terinary Medicine; accompanying it only with this single remark, that although the theory is highly ingenious, and does much credit to its observant author, the changes arc too liable to irregularity and variation to have implicit reliance placed upon them.
" In order to tell the age of a horse that has passed his 8th year, we must know that an incisive tooth, (considered as a whole) when extracted from its socket, is of a curved pyramidal figure, and, while fixed within the jaw, the part exterior to the gum presents an oval outline, thus c; of which form it continues until the loth or 1 lth year. After this it begins to take on, and about the 14th year fully assumes the circular figure, O. From the 14th to the 17th year, it grows triangular. And from this period inclines to, and ever afterwards retains, an oval figure turned contrariwise from its original form, 0." Those who may feel desirous to prosecute their inquiries into this and other departments of vete rinary knowledge, will consult with most advan tage, among the English writers, Coleman, Clarke, Blaine, and Percivall; among the French, Lafosse, Girard, and Hurtrel d'Arboval.