tion
of the nerves is only effected by means of the more subtle parts of the
humidity of the brain, which are sucked up by the roots or extremities
of the nerves, and are carried thence through all the branches of the
sensory system. This system forms, as we have said, a whole, all whose
parts are interconnected by so close a union that we cannot wound one
without communicating a violent shock to all the others; the wounding or
simply pulling of the smallest nerve is sufficient to cause lively
irritation to all the others, and to put the body in convulsion; nor can
we ease this pain and convulsion except by cutting the nerve higher up
than the injured part; but on this all the parts abutting on this nerve
become thenceforward senseless and immovable for ever. The brain should
not be considered as of the same character, nor as an organic portion of
the nervous system, for it has not the same properties nor the same
substance, being neither solid nor elastic, nor yet capable of feeling.
I admit that on its compression perception ceases, but this very fact
shows it to be a body foreign to the nervous system itself, which,
acting by its weight, or pressure, against the extremities of the
nerves, oppresses them and stupefies them in the same way as a weight
placed upon the arm, leg, or any other part of the body, stupefies the
nerves and deadens the perceptions of that part. And it is evident that
this cessation of sensation on compression is but a suspension and
temporary stupefaction, for the moment the compression of the brain
ceases, perception and the power of movement returns. Again, I admit
that on tearing the medullary substance, and on wounding the brain till
the _corpus callosum_ is reached, convulsion, loss of sensation, and
death ensue; but this is because the nerves are so entirely deranged
that they are, so to speak, torn up by the roots and wounded all
together, and at their source.

"In further proof that the brain is neither the centre of perception nor
the seat of the sensations, I may remind the reader that animals and
even children have been born without heads and brains, and have yet had
feeling, movement, and life. There are also whole classes of animals,
like insects and worms, with a brain that is by no means a distinct mass
nor of sensible volume, but with only something which corresponds with
the _medulla oblongata_ and the spinal marrow. There would be more
reason, then, in placing the seat of the