In the same way, air-waves striking the ear are communicated by the auditory nerve to the brain, where they awaken a corresponding sensation of sound. But these waves must be vibrating
at between 30 and 20,000 times a second. If they are vibrating so slowly or so rapidly as not to come within this range, we cannot hear them.
The Living Telegraph
This process is by no means a mechanical affair. On the contrary, it is a series of mental acts. Every cell in the living telegraph must receive the message and transmit it. Every cell must exercise a form of intelligence, from the auditory cell reporting a sound-wave or the skin cell reporting an injury to the muscle cells that ultimately receive and understand a message directing them to remove the part from danger.
Reaction-time, so called, is thus occupied by cellular action in the form of mental processes intervening between the
nerve-ends and the brain center, in much the same way that light and sound vibrations intervene between the object perceived and the surface of the body.
The Six Steps to Reaction
For even the simplest of sense-perceptions we have, then, this sequence of events: first, the object perceived; second, the series of vibrations of ether particles intervening between the object and the body; third, the impression upon the surface of the body; fourth, the series of mental processes, cell after cell, in the nerve filaments leading to the brain; fifth, when these impressions or messages have reached the brain, a determination of what is to be done; and, sixth, a transmission by cellular action of a new message that will awaken some response in the muscular tissues.
Unopened Mental Mail