1st, then, as respects the individual, we learn as follows: 'Even
while the cerebral hemispheres are entire, and in full possession of
their powers, the brain gives rise to actions which are as
completely reflex as those of the spinal cord.

'When the eyelids wink at a flash of light, or a threatened blow, a
reflex action takes place, in which the afferent nerves are the
optic, the efferent, the facial. When a bad smell causes a grimace,
there is a reflex action through the same motor nerve, while the
olfactory nerves constitute the afferent channels. In these cases,
therefore, reflex action must be effected through the brain, all the
nerves involved being cerebral. 'When the whole body starts at a
loud noise, the afferent auditory nerve gives rise to an impulse
which passes to the medulla oblongata, and thence affects the great
majority of the motor nerves of the body. 'It may be said that these
are mere mechanical actions, and have nothing to do with the acts
which we associate with intelligence. But let us consider what takes
place in such an act as reading aloud. In this case, the whole
attention of the mind is, or ought to be, bent upon the subject-
matter of the book; while a multitude of most delicate muscular
actions are going on, of which the reader is not in the slightest
degree aware. Thus the book is held in the hand, at the right
distance from the eyes; the eyes are moved, from side to side, over
the lines, and up and down the pages. Further, the most delicately
adjusted and rapid movements of the muscles of the lips, tongue, and
throat, of laryngeal and respiratory muscles, are involved in the
production of speech. Perhaps the reader is standing up and
accompanying the lecture with appropriate gestures. And yet every
one of these muscular acts may be performed with utter
unconsciousness, on his part, of anything but the sense of the words