The outer end of every sensory nerve exposes a sensitive bit of gray matter. These sensitive, impression-receiving ends constitute together what is called the "sensorium" of the body.
When vibrations of light or sound impinge upon the sensorium, they are relayed from nerve cell to nerve cell until they reach the central brain. Then it is, and not until then, that sensations and perceptions occur.
Consider, now, the infinitesimal size of a nerve cell and you will have some conception of the number of hands through which the message must pass before it is received by the central office.
Many of our sensations, especially those of touch, seem to occur on the periphery
of the body—that is to say, at that part of the exposed surface of the body which is apparently affected. If your finger is crushed in a door, the sensation of the blow and the pain all seem to occur in the finger itself.
The Place Where Sensation Occurs
As a matter of fact, this is not the case, for if one of your arms should be amputated, you would still feel a tingling in the fingers of the amputated arm. Thus has arisen a superstition that leads many people to bury any part of the body lost in this way, thinking that they will never be entirely relieved of pain until the absent member is finally at rest.
Of course, the fact is that you would only seem to have feeling in the amputated arm. The sensation would really occur
in the central brain tissue as the organ of the governing intelligence, the organ of consciousness.
Laboratory Proof of Sense-Perceptive Process