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OF THE GROWTH OF THE TWO JAWS. 141
art be fixed, as it was one of the Teetli that is naturally shed,
and that another might come in its place : however she was
disappointed.
These cases prove evidently, that in shedding, the first Teeth
are not pushed out by the second set, but that they grow loose,
and fall out of their own accord. That the succeeding Teeth have
some influence on the shedding of the temporary set is proved
by those very cases ; since in one of the first mentioned the person
was above twenty years of age, and in the other the lady was
thirty ; and it is reasonable to believe, that the shedding of
these Teeth was so late in those instances, from the want of the
influence, whatever it is, of the new Teeth. When the Incisores
and Guspidati of the new set are a little advanced, but long
before they appear through their bony sockets, there are small
holes leading to them on the inside, or behind the temporary
sockets and Teeth ; and these holes grow larger and larger, till
at last the body of the Tooth passes quite through them.(&)

OF THE GROWTH OF THE TWO JAWS.
As a knowledge of the manner in which the two Jaws grow,
will lead to the better understanding the shedding of the Teeth ;
and as the Jaws seem to differ in their manner of growing, from
other bones, and also vary according to the age, it will be here
proper to give some account of their growth.
In a Foetus three or four months old, we have described the

(jfc) [The process by which the fang of the milk-tooth becomes absorbed
is not at present understood. The partition which separates the alveolus
of the milk from the permanent tooth becomes removed, so that the
latter comes to lie under the former, and as the permanent tooth ad-
vances, the milk, already loosened by the absorption of its fang from
The small holes erroneously stated in
below upwards, gives place to it.
the text to be the commencement of openings through which the perma-
nent teeth are to pass are the foramin through which the cords pass con-
necting the permanent tooth-sacs with the gum. {Vide Note, a. p. 3 13.)]