These two great hemispheres are distinct bodies, each complete in itself but united by fibres that pass from one hemisphere to the other and thus secure their united action. These fibres are observed to connect together corresponding regions of the two hemispheres.
At their bases the two hemispheres are in direct contact with the ganglion above described as the central ganglion, but which has been anatomically subdivided into two pairs of ganglia. For the purposes of this treatise, however, minute divisions are not necessary.
This ganglion is the centre upon which all the nerves of the senses converge and each division of it is supposed to be appropriated to a distinct sense. But even if each part has its own work to do, it is not less a whole than is the cerebral hemisphere, which is now proved to have various parts devoted to various mental operations.
The cerebral hemispheres are formed of great bundles of fibres, in the shape of rolls, plainly visible on the outside, but which baffle the attempts of the most dexterous anatomist to sever them below the surface.
And the whole brain is covered with an extremely delicate and highly sensitive membrane, which is now conjectured to be the medium by means of which all the parts of the brain are brought into communication, and the co-ordination and unity of action of the entire organ preserved.
The substance of the brain itself is insensible, although it is the recipient and supposed seat of the pains and pleasures of the body—or rather of the nerves, for what we call the body is only the insensible clothing of the nerves. The nerves feel; the flesh and bones do not feel.
Is not this fact another powerful argument against the doctrine of the Materialists that consciousness and mind are only states of brain or conditions of matter? If the brain is not conscious of injuries done to itself, if it is insensible even to its own destruction, how can it be the “Conscious Self?”
But the enveloping membrane of the brain is exquisitely sensitive. It is the seat of headache, of delirium tremens, of brain fever, of hydrocephalus, and probably of many more diseases which we are wont to refer to the substance of the brain.
We refer—Who refers? What refers? The brain to the brain? Or one part of the brain to another part of the brain? Will the Materialists explain?
It is probable that this envelope of nerves unites all the parts of the brain and by transmitting to each part the condition of all the other parts produces co-ordination of the parts and unity of action. But this membrane of nerve cannot surely be deemed by the most bigoted Materialist to constitute the Conscious Self.