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30 Natural History of the J^eth,
the true type,* from which all others are mere deviation*;
hence by comparing the teeth of men, with those of other ani-
mals, it is impossible to arrive at any conclusion, as to what

"On the subject of diet a question naturally presents itself; whi tlier
man approaches most nearly to the carnivorous or herbivorous tribes in
his structure? What Kind of food should we assign him, if we judged
from his organization merely, and the analogy it presents to that of
other mammalia? Physiologists have usually represented that our
species hold a middle rank in the masticatory and digestive apparatus,
between the fhsh eating and the herbivorous animals;— a statement
which seems rather to have been deduced from what we have learned by
experience on this subject, than to result fairly from an actual compari-
son of men and animals.
"The molar teeth being the instruments employed in dividing and prepar-
ing the food, must exhibit in figure and construction a relation to the nature
of the aliment. They rise in the true carnivora, into sharp pointed prominen-
ces ; and those of the lower shut within those of the upper jaw ;—when
the series is viewed together, the general outline may be compared to
the teeth of a saw. These an'mals are also furnished with long pointed,
and strong cuspidati or canine teeth, which are employed as weapons of
offense and defence, and are very serviceable in seizing and lacerating
their prey; they constitute in some animals, as the lion, tiger, &c. very
formidable weapons. The herbivorous animals are not armed with these
terrible canine teeth ; their molares have broad fiat surfaces, opposed in
a vertical line to each other in the jaws. Plates of enamel are intermixed
with the bone of the teeth in the latter, and as its superior hardness
it appears
makes it wear less rapidly than the other textures of the teeth,
on the grinding surface in rising ridges, which must greatly increase the
triturating effect. In carnivorous animals the enamel is confined alto-
gether to the surface of the teeth.
" The articulation of the lower jaw differs in the two eases as much as
the structure of the teeth. In the carnivora, it can only move backwards
and forwards, all lateral motion being prevented by the rising edges of
the glenoid cavities : in the herbivora it has, moreover, motion from side
to side. Thus we observe in the flesh-eaters, teeth calculated only for
tearing, subservient, in parts at least, to procuring of food, as well as to
purposes of defence; and an articulation of the lower jaw, that precludes
all lateral motion. In those which live on vegetables, the form of the
teeth and the nature of the joint, are calculated lor the lateral or grind-
ing motion. The former, having rudely torn and divided the food, swal-
low it in masses; while in the latter it undergoes considerable commi-
nution before it is swallowed. The teeth of man have not the slightest
resemblance to those of the carniverous animals, except that their enamel
is confined to the external surface ; he possesses, indeed, teeth called
canine, but they do not exceed the level of the others, and are obviously
unsuited to the purposes which the corresponding teeth execute in car-
nivorous animals. The obtuse tubercles of the human molares have not
the most remote resemblance to the pointed projections of these teeth in
carnivorous animals; they are as clearly distinguished from the flat
erowns, with intermixed enamel, of the herbivorous molares. In the free
* Thomas Bell.