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OF THE FORMATION OF TIIE ENAMEL. 135
cavity of the Tooth shoot across where the Pulp adheres to the
Jaw, meet in the middle, and thereby divide the mouth of the
cavity into two openings ; and from the edges of these two
openings the two fangs grow.
"We often find that a distinct ossification begins in the middle
of the general cavity upon the root of the Pulp, and two pro-
cesses coming from the opposite edges of the bony shell join it
which answers the same purpose.
When there are three fangs, we see three processes coming
from so many points of the brim of the cavity, which meet in
the center, and divide the whole into three openings ; and from
these are formed the three fangs. We often find the fangs
forked at their points, especially in the Bicusjrides. In this
case, the sides of the fang as it grows, come close together in
the middle, making a longitudinal groove on the outside ; and
this union of the opposite sides divides the mouth of the grow-
ing fang into two orifices, from which the two points are
formed.
By the observations which I have made in unravelling the
texture of the Teeth, when softened by an acid, and from
observing the disposition of the red parts in the Tooth of grow-
ing animals, interruptedly fed with madder, I find that the bony
part of a Tooth is formed of Lamella, placed one within another.
The outer Lamella is the first formed, and is the shortest : the
more internal Lamella lengthen gradually towards the fang, by
which means, in proportion as the Tooth grows longer, its
cavity grows smaller, and its sides grow thicker.
How the earthy and animal substance of the Tooth is
deposited on the surface of the pulp is not perhaps to be
explained.
OF THE FORMATION OF THE ENAMEL.
In speaking of the Enamel we postponed treating of its For-
mation, till it could be more clearly understood ; and now we
shall previously describe some parts which we apprehend to be
OF THE FORMATION OF TIIE ENAMEL. 135
cavity of the Tooth shoot across where the Pulp adheres to the
Jaw, meet in the middle, and thereby divide the mouth of the
cavity into two openings ; and from the edges of these two
openings the two fangs grow.
"We often find that a distinct ossification begins in the middle
of the general cavity upon the root of the Pulp, and two pro-
cesses coming from the opposite edges of the bony shell join it
which answers the same purpose.
When there are three fangs, we see three processes coming
from so many points of the brim of the cavity, which meet in
the center, and divide the whole into three openings ; and from
these are formed the three fangs. We often find the fangs
forked at their points, especially in the Bicusjrides. In this
case, the sides of the fang as it grows, come close together in
the middle, making a longitudinal groove on the outside ; and
this union of the opposite sides divides the mouth of the grow-
ing fang into two orifices, from which the two points are
formed.
By the observations which I have made in unravelling the
texture of the Teeth, when softened by an acid, and from
observing the disposition of the red parts in the Tooth of grow-
ing animals, interruptedly fed with madder, I find that the bony
part of a Tooth is formed of Lamella, placed one within another.
The outer Lamella is the first formed, and is the shortest : the
more internal Lamella lengthen gradually towards the fang, by
which means, in proportion as the Tooth grows longer, its
cavity grows smaller, and its sides grow thicker.
How the earthy and animal substance of the Tooth is
deposited on the surface of the pulp is not perhaps to be
explained.
OF THE FORMATION OF THE ENAMEL.
In speaking of the Enamel we postponed treating of its For-
mation, till it could be more clearly understood ; and now we
shall previously describe some parts which we apprehend to be
