s
of skin and muscle. His subdivision of the post-central gyrus is based
on histological differences which he discovers between its anterior and
its posterior parts and on the above-described analogous differentiation
of a "sensory" from a "psychic" part in the visual region of cortex.

It will be noted that although certain regions of the cortex are found
connected closely with certain of the main sense organs, there are
important receptive organs which do not appear to have any special
region of cortex assigned to their sensual products. Thus, there is the
"vestibular labyrinth" of the ear. This great receptive organ, so
closely connected in function with the movements and adjustment of the
postures of the head and eyes, and indeed of the whole body, is
prominent in the co-ordination necessary for the equilibrium of the
body, an essential part of the fundamental acts of progression,
standing, &c. Yet neither structural nor functional connexion with any
special region of the cortex has been traced as yet for the labyrinthine
receptors. Perceptions of the position of the head and of the body are
of course part of our habitual and everyday experience. It may perhaps
be that these perceptions are almost entirely obtained through sense
organs which are not labyrinthine, but visual, muscular, tactual, and so
on. The labyrinth may, though it controls and adjusts the muscular
activities which maintain the balance of the body, operate reflexly
without in its operation exciting of itself sensations. The results of
the unconscious reflexes it initiated and guided would be perceptible
through other organs of sense. But against this purely unconscious
functioning of the labyrinth and its nervous apparatus stands the fact
that galvanic stimulation of the labyrinth is accompanied by well-known
distinctive sensations--including giddiness, &c. Moreover, the prominent
factor in sea-sickness, a disorder richly suffused with sensations, is
probably the labyrinth. Yet there is marked absence of evidence of any
special and direct connexion between the _cortex cerebri_ and the
labyrinth organs.

Also there is curiously little evidence of connexion of the cortex with
the nervous paths of conduction concerned with pain. As far as the
present writer can find from reference to books and from the clinical
experience of others, "pain" is unknown as an _aura_ in cortical
epilepsy, or at most is of equivocal occurrence.

The preceding brief expo