Cheraw gazette. [volume] (Cheraw, S.C.) 1835-1838, 1837-02-14
From ComJc'S Physiology of Digestion.
THE TEETH.

three distinct groups 1st, The incisor q
cutting teeth. being :he eight broad or flat
teeth, with sharp cutting edge, seen IN
from Of the upper and lower jaws. 81, The
cuspuati, canine, or dog teeth, being the
sharp. pointed, roundish- bodied teeth, four
in number, in contract with each of the outer
incisor teeth, and called canine from being
large in the dog and carnivorous animals,
and used by them for the purpose OF Set='nS
and tearing heir food; and Sd, The moIares
or grinders, twenty in number, situated at
the back part Of lie jaw, and so called from
their office being to grind or bruisc the food
subjected 10 their &C ion.& The term grind
ers however, is sometimes restricted to the
three back teeth on each side, and seen to
have double roots and broad grinding sur
face, and the TWO intervening between them
and the cuspidati are styled bicuspidati, or
double. speared, from bearing greater re-
semblance to a double headed canine tooth
than to the other grinders.
The teeth are modified in different ami.
mails to suit their habits oflfc. In herbiv-
orous animals, the canine teeth, for which
they have no use, are comparatively unde-
vclopcd whereas in carnivorous animals,
which tear their prey in pieces, the canine
teeth arc large, powerful, and pointed, and
The inciSorS comparatively round. In these
animals they constitute what are properly
called the tuSks, and in some species they
are Of 4 truly formidable character. The
molar, Or grinding teeth, differ in like man.
ner, according 20 the nature of the food. In
herbivorous and granivorous animals they
are large and powerful, and to increase their
efficacy the lower jaws admit of consld-
cradle lateral motion in horizontal dlrec-
ton; whereas, in carnivorous animals, it
admits of motion only upwards and down.
wards, as in opening and shutting the mouth.
The lateral grinding motion is very evident
in Eliminating animals, such as the COW,
which, after having filled its stomach with
provendcr. is generally seen TO lie down and
ruminate or cheu the cud, as ii is called
the ruminaton consisting in bringing up
small masses ofhcrbage from the somach,
and submi ting them to thorough mastica.
ton or grinding between its moar teeth, be-
fore being again swallowed and digcstcd.
From this relation between the food and
the organs of mastlcaton, naturasts can
tell with certainty, by simply inspecting the
teeth. on what kind of food the animal TO
Which they belong is intended TO live; and
as the teeth ofman partake of the charac-
tcrs of those Of both hcrbivorous snd car
nivorous animals, there cannot be doubt
that his diet was intended TO be of mixed
kind, no. confined cxclu;:yely to either the
vegetable or the animal kingdom.
Hard and resisting as the teeth appear,
they must still be regarded as living struc.
turcs. Anatomically speaking. each tooth
is divided into three parts: the fang, or root,
implanted in the socket of the !iawbone; the
neck, or portion cncircled by the gum; and
TIC whi;c crown, appearing above the gum,
and covered with enamel.
The root Of each Doth is perforated lon-
giudinaIv by small canal, through which
| the boodvcssels and nerve are admitted to
lis central parts. From these boodvessels
the tooth derives its nourshmcnt when
growing; bit they aferward almost entirely
| disappear. From the nerve 1t derives that
sensiblity which makes us instantly aware
! Of the contact of bodies either too ho: or too
cold with the teeth; and which, when the
nerve is diseased, gives rise TO the raclllng
pain Of toothachc.
SO ehactuany is life maintained in the
teeth bv this provision ofvesscls and nerves,
that tooth newly extracted from the socket
OF a Young animal, and implanted in the
neshv comb Of a cock. has been found TO
adhere and retain its vitality; and in like
manner, If, in early life, a tooth extracted by
accident be Immediately replaced in its
socket, it will generally adhere and live.
The visible part, or crown of the tooth, Is
covered with very hard, white, ivory
looking substance, called enamel, which
serves to prevent it from being worn down
bv friction, and into which neither bloodvcs-
scls nor nerves have been obscrvedto pcnc-
tra:e. Owing TO this structure, the tooth
can be safely exposed without sustaining
damage--a privilege on which most persons
will b. disposed to place higher value al
ter having experienced the pains conse-
!, quenfupon injury Of the nerve from 4 ror-
ton OF the enamel being broken off.
An obvious advantage attending tine Vi
tali!v Of the teeth is, that it enables them 10
accommodate themselves to the growth OF
the Jaw and the rest of the system at the diff.
fcrcnt periods Of life. In early infancy,
when the human being is designed TO live
exclusively Oh his mothers milk, which o.
course requires no mastification, and con
scouentlv no teeth, the latter arc still i'm
perfectly formed and entirely hidden in The
law: i, is only at the end ofsomc months tha
the front or cutting teeth begin to appear: &
: the whole set of milk, deciduous, or falling
. fc onnanln