According to recent teaching, the physical can be followed as such from the sensory end-organ itself as far as the first synapse, or junction with the neurone. But there something happens; ... then it reappears in a new guise, vibration becomes sensation, the physical psychic, the objective subjective, the real ideal, the dead alive! In that brief tumble of time what a miraculous transformation!
Modern science has cleared up much of the mystery of the objective world, and although it may be far from the end of its search, although, indeed, the search, one must think, can never entirely elucidate the dense obscurity that envelops us on every side, dark as a starless night around a candle, yet we already know this much, that the real world is very different from the world depicted for us by our senses.
Only a little imagination is needed to convey us out of the magic circle into which we have been born, and what a strange universe do we then find ourselves in! Entangled in a meshwork of space-time and permeated by whirling maelstroms of varied and innumerable oscillations, we lose all hold on reality in the very act of grasping it.
But although we do possess some sort of vague notion as to the constitution of the outer universe, before the inner we stand ignorant and speechless.
Regarded as a machine, the brain, it is true, like the world without, is reluctantly yielding up its secrets one by one. We are learning how it works as a chemical factory, as a physical power-house, so that already we can surmise that here also we have probably to deal with a multiplicity of vibrations, of exquisitely minute transformations of energy, of involved intercommunications, of deft though intricate associations, of rapid yet permanent recordings and registrations.
We are now able to follow the undulations we term light, not only into the eye, but into the brain itself, locating their central station in the occipital lobe, whence their effects radiate all over the organism. And in the case of olfaction Pawlow has taught us that its chief vegetative function, the result of radiations from the olfactory central station in the brain, is the arousing of the digestive glands to activity. The first act of digestion is olfaction. But the routes which the olfactory stimuli follow in the central nervous system and their communications with other sensory paths are not yet known.
The secrets of the brain which have been disclosed to us, however wonderful they may be, concern only, we must remember, the machinery of the nervous system, that part, namely, which is of the same nature and order as the objective world, of which indeed it is a member. Hitherto have we come, but no further:
“The traveller hails. The echoing walls respond.
And there the matter ends. The wilds beyond
Are broken rock and desert where no foot