On the knowledge of the age of the horse by his teeth. With remarks / [Bracy Clark].

  • Bracy Clark
Date:
1826
Catalogue details

Licence: Public Domain Mark

Credit: On the knowledge of the age of the horse by his teeth. With remarks / [Bracy Clark]. Source: Wellcome Collection.

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    crown of it in a position almost perpendicular at its first emerging from the jaw, and occasions it to meet the teeth of the opposite or upper jaw nearly perpendicularly; but as the tooth wears away, and, in very advanced age, after passing through a succession of inclining angles, is at last reduced to the shank, which being placed nearly in the direction of the jaw itself, will oc- casion these teeth to meet the opposing teeth of the upper jaw in nearly an horizontal line, so that their internal lateral surfaces get worn, instead of their points, into an oblong irregular figure, and the reduced lean jaw bones approach each other in the same direction, the redundant skinny lips are seen protruding beyond the teeth; whereas in the youthful jaw these parts are rounded, plump, and deep in front. Accessions to the fang or posterior parts of these front teeth are made to almost the latest period of life, which accessions are flattened in the opposite direction to the compressed flatness of the crown of the fresh tooth, and thus diminish the lateral extent of the jaws. And these prolongations are, after a certain age, of solid bone, without enamel, of a yellowish colour, and very hard. In the centre of the crown of the tooth, and externally visible, is an inverted hollow or funnel of enamel, which we have called the infundibulum; it has bqen called the mark by dealers, and is supposed by them to fill and grow up, but is in reality worn away by the use of the teeth, and obliterated about the sixth year. The primitive germs and formation of both sets of teeth, must be sought in the foetus some months before birth; but the circumstances attending the growth and progress of the teeth generally, are most beautifully to be observed by the dissection of the jaw of a horse two years old previous to their shedding a tooth. On carefully taking the jaw to pieces, we may observe underneath the two front milk Incisors, and lying within them, the front pair of the second set, now about one inch and three quarters long, consisting of hardly anything more than a shell of enamel, with the small enamel inverted cone coming down the inside of it from the crown, and tapering to a point; this hollow tube is now of the full size of the tooth, and requires only to be strengthened with bony matter for being brought into use. The second pair of Incisors are only one inch long, con- sisting of a shorter case of enamel, covered with a brown furred matter of an ochre colour, and the inverted enamel cone within is not closed at the point, so that you see through it. The enamel in both the cone and the
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