In his desire to bring relief to the deaf--and his whole life has been
devoted to that object--Professor Bell has begun a series of
remarkable experiments in this line. Some time ago, he determined to
study the effects produced upon the brain by turning an electric
current into it through the side of the head. With this end in view,
he arranged a dynamo machine with a feeble current, giving a varying
number of interruptions per second, and attached one of the poles to a
wet sponge which he placed in one of his ears.
"I risked one of my ears," he said simply, "in making this experiment,
but I could not risk them both, so I held the second pole of the
machine in my hand and turned on the current."
Fortunately no harm resulted, but immediately Professor Bell
experienced the sensation of a pleasant sound whose pitch he was able
to vary by increasing or diminishing the number of interruptions in
the dynamo machine. His assistant standing beside him could detect no
sound at all, so that what Professor Bell heard must have been the
effect of the electric current upon his brain. This effect he found
could be varied by varying the character of the current. Now he argues
that greater variations might be produced in the sounds heard by the
brain if the current turned into it were varied in the proper manner.
For instance, suppose the current from a long distance telephone to be
turned through the head of the deaf mute, a sponge connected with
either pole being placed in each ear. Then let some one talk into the
telephone in the ordinary way, the infinite variations in the current
produced by the voice vibrations being passed into the brain directly.
Is it not conceivable that such a variety of brain sensations or tones
might then be caused in the head of the deaf mute as to make it
possible to establish a system of sound signals, so to speak, which
would be the equivalent of ordinary language? Indeed, is it not
possible that the deaf mute might actually hear spoken words?
Professor Bell's experiments upon himself have been so encouraging as
to make him disposed to try more complete experiments in the same line
upon persons who have lost all sense of hearing, and who would
doubtless be willing to take the inevitable risk for the sake of the
great blessing which a successful issue would bring to them.
We talked a long time about these strange fancies, and finally I said
to Professor Bell:
"But on this principle of brain tickling, what is to prevent a blind
man from seeing by electricity?"
"I do not know that there is anything to prevent it."