nfidence in our ability to judge and compare living heads and skulls
of man and animals.

[Illustration]

Let us take an exterior view by removing one half of the skull from
the right side of the head. This enables us to see that the front
portion of the brain rests above the sockets of the eyes, coming down
in the centre as low as the root of the nose, but a little higher
exteriorly. When we touch the forehead just over the root of the nose,
our finger touches the lowest level of the front lobe, the seat of the
intellect; but when we touch the external angle of the brow on the
same level, we touch a process of bone, and our finger is fully half
an inch below the level of the brain.

In the posterior view we see that below the great mass of brain which
is called the cerebrum there lies a smaller body, shaped much like a
small turnip, called the cerebellum or little brain, separated from
the cerebrum by a firm, horizontal membrane called the tentorium
(covering the cerebellum), on which the cerebrum rests.

[Illustration]

The position of the tentorium can easily be ascertained in your own
head by the fact that where it crosses the median line there is a
little projection of bone called the occipital knob, very prominent on
some persons, barely perceptible on others. After locating the
occipital knob, a horizontal line forward will give us the portion of
the tentorium. When we carry this line forward just over the cavity of
the ear, thus locating the tentorium, we easily recognize below it the
rounded prominence on each side in which the two hemispheres or halves
of the cerebellum lie, with a depression between them on the median
line. To make these and other observations on the head (which no one
should neglect), the hand should be placed firmly on the scalp, so
that as it slides on the bone we feel the form of the skull beneath.
In most persons a distinct depression will be felt along the line of
the tentorium, separating the cerebrum and cerebellum--the cerebellum
being located at the summit of the neck, and extending down about as
low as the end of the mastoid process, which is the large, long
prominence just behind the cavity of the ear.

The cerebellum may be regarded as the physiological and the cerebrum
as the psychic brain, for the cerebellum is void of intelligence and
volition, but has important influences on the body. It may be
considered, like the spinal cord, an intermediate structure between
the co