my of the teeth._
213. What confines the teeth in the jaw-bone? What becomes of the
socket when a tooth is removed? What effect has this absorption upon
the jaw and lips?

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214. The teeth are formed in the interior of the jaws, and within
_dent'al cap'sules_, (membranous pouches,) which are enclosed within
the substance of the bone, and present in their interior a fleshy bud,
or granule, from the surface of which exudes the ivory, or the bony
part of the tooth. In proportion as the tooth is formed, it rises in
the socket, which is developed simultaneously with the tooth, and
passes through the gum, and shows itself without.

[Illustration: Fig. 54. 1, The body of the lower jaw. 2, Ramus, or branch
of the jaw, to which the muscles that move it are attached. 3, 3, The
processes which unite the lower jaw with the head. _i_, The middle and
lateral incisor tooth of one side. _b_, The bicuspid teeth. _c_, The
cuspids, or eye teeth. m, The three molar teeth. A, shows the relation of
the permanent to the temporary teeth.]

215. The first set, which appears in infancy, is called _tem'po-ra-ry_,
or milk teeth. They are twenty in number; ten in each jaw. Between
six and fourteen years of age, the temporary teeth are removed, and the
second set appears, called _per'ma-nent_ teeth. They number
thirty-two, sixteen in each jaw.

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214. Where and how are the teeth formed? Explain fig. 54. 215. What
are the first set called? How many in each jaw? The second set? How
many in number?

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216. The four front teeth in each jaw are called _in-ci'sors_,
(cutting teeth;) the next tooth in each side, the _cus'pid_, (eye
tooth;) the next two, _bi-cus'pids_, (small grinders;) the next two,
_mo'lars_, (grinders.) The last one on each side of the jaw is called
a _wisdom tooth_, because it does not appear until a person is about
twenty years old. The incisors, cuspids, and bicuspids, have each but
one root. The molars of the upper jaw have three roots, while those of
the lower jaw have but two.

[Illustration: Fig. 55. The permanent teeth of the upper and lower jaw.
_a_, _b_, The incisors. _c_, The cuspids. _d_, _e_, The bicuspids. _f_,
_g_, The molars, (double teeth.) _h_, The wisdom teeth.]

_Observation._ The shape of the teeth in different species of animals
is adapted to the kind of food on which they subsist. Those animals
that feed exclusively on flesh