And you may set it down as an established principle that all states of consciousness, whether seemingly localized on the surface of the body or not, are connected with the brain as the dominant center.
The facts we have been recounting have been established by the experiments of physiological psychology. Thus, the work of the laboratory has shown that between the moment when a sense vibration reaches the body and the moment when sensation occurs a measurable interval of time intervenes.
If your eyes were to be blindfolded and your hand unexpectedly pricked with
a white-hot needle, the time that would elapse before you could jerk your hand away could be readily measured in fractions of a second with appropriate instruments.
Reaction Time
This interval is known as reaction-time. It varies greatly with different persons. During this reaction-time, the cell or cells attacked upon the surface of the hand have conveyed news of the assault through numberless intermediate sensory nerve cells to the brain. The brain in turn has sent out its mandate through the appropriate motor nerve cells to all the muscle and other cells surrounding the injured cell, commanding them to remove it from the point of danger.
The work of the nervous system in dealing
with the ether vibrations that are constantly impinging upon the surface of the body has been likened to that of the transmitter, connecting wire and receiver of a telephone. Air-waves striking against the transmitter of the telephone awaken a similar vibratory movement in the transmitter itself. This movement is passed along the wire to the receiver, which vibrates responsively and imparts a corresponding wave-like motion to the air.
The Human Telephone
These air-waves when heard are what we call sound.