Page 45 - My FlipBook

Of the Peimanenl Teeth. 2.1
-OF THE PERMANENT TEETH.
The formation of the permanent teeth exhibits some of the
most curious changes in the animal economy.. The permanent
teeth are produced from the sacks of the temporary ones by a
process which reminds us of gemmiparous reproduction in the
lower classes of animal and vegetable life.
The investing sack of the temporary tooth gives off a small
process or bud, containing the essential rudiments of the per-
manent tooth, namely, tha pulp, covered by its investing
membranes'.
" It commences," says Mr. Bell, (i. e. the rudiment of the
permanent tooth) " in a small thickening on one side of the
parent sack of the temporary tooth, which gradually becomes
more and more circumscribed, and at length assumes a distinct
form though still connected by a peduncle (stem.) For a time,
ihe new rudiment is contained in the same alveolus with its
parent, which is excavated by the absorbents for its reception
by a process, as far as I am acquainted unparalelled in the
phenomena of physiology ; unless indeed the absoption of the
roots of the temporary teeth may be considered as analogous.
By degrees a small recess is formed by this peculiar process of
absorption in the walls of the socket, in which the new rudi-
ment is lodged, and this excavation continues to increase with
the increasing size of the rudiment, whilst at the same time,
the maxillary bone becomes enlarged, and the temporary tooth,
advancing in its formation, rises in its socket, and the new cell
Was in one or two instances so exquisitely effected as to deceive almost
every spectator, when the trick was first brought forward, and to lay a
foundation for no small number of learned descriptions and profound ex-
planations upon the subject."
I have repeatedly been informed that there is an old lady living at
Athens, opposite Hudson, on the North River, who lately cut a partial set
of teeth at 83 years of age. I have not had an opportunity to enquire intd
the truth of this report; though from the respectability of my informants,
I doubt not its correctness. Mr.- Parmly mentions in his notes to Brown's
JDentologia, that he has been repeatedly informed that there is a whole
family, residing in South Carolina, who have never cut any teeth, ths
alveolar processes being so much elongated, as to obviate the deformity
that would otherwise have been the consequence*
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