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lower teeth directly under their corresponding teeth in the
upper jaw ; this is done either in the dividing or holding of
substances, and these are the teeth that are generally used in
the last mentioned action. When the true grinding motion
is to be performed, a greater degree of this last motion
takes place ; that is, the condyle of the opposite side is
brought farther forwards, and the condyle of the same side
is drawn farther back into the cavity of the temporal bone,
and the jaw is a little depressed. This is only preparatory
for the effect to be produced ; for the moving back of the
first mentioned condyle into the socket, is what produces the
effect in mastication.
The lateral teeth in both jaws are adapted to this oblique
in the lower they are turned a little inwards, that
motion ;
they may act more in the direction of their axis ; and here
the alveolar process is strongest on the outside, being there
supported by the ridge of the root ofthe coronoid process. In
the upper jaw the obliquity of the teeth is the reverse, that is,
they are turned outwards, forthe same reason ; and the longest
fan strengthened by the bony partition between the antrum and
the nose. Hence it is, that the teeth of the lower jaw have
their outer edges worn down first ; and vice versa, in the
upper jaw."

SECTION XI.
TJSUS DENTIUM.

The first and principle of these is for the comminution of
the food, whence toothless persons feed only on fluids. It

Bartholinus' Anatomy Lugduni, Batava. 1686.
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