Page:Popular Science Monthly Volume 46.djvu/660

642 these impressions and evolve new combinations of them, which are rendered manifest externally by impulses sent through a set of outgoing fibers to the various organs of motion.

A diagram is here reproduced showing the localized areas of sight, hearing, touch, etc., in the human brain, and their relation to the motor centers. It should be stated, in passing, that these centers are in duplicate, or pairs—one of each on each side of the brain.

The purpose of this article is to show by numerous facts that, when one of the senses is lost by accident, or when it is congenitally absent, the other senses, in persons otherwise normally constituted, become preternaturally keen, and this in a way to compensate in some degree for the loss of power in the disabled or absent sense. It is this that I have ventured to call the "Mutual Aid Society of the Senses."

The historian William H. Prescott, of Boston, who was himself blind, used to say that "the blind man saw little outside of the circle drawn by his extended arms, but that within that circle he saw more than those whose eyes were sound."

In considering my subject I will first narrate a very curious illustration of the strangely wayward, atavistic recurrence of blindness, deafness, and idiocy in collateral branches of an originally tainted stock.

I am indebted to Dr. A. Graham Bell for a very interesting story about a little hamlet in a certain isolated portion of New England. He happened accidentally at one time to come across a gentleman resident in that section who had an immense mass of genealogical statistics (made out on little slips of paper which he kept stuffed in different small bags) covering the family trees not only of his own neighbors, but also of descendants of the old stock now scattered all over New England.

From this unique material, which Dr. Bell has helped to put in usable shape, he became acquainted with the fact that this hamlet was a very peculiar little town, and had been so for twelve generations—ever since its original settlement. Its peculiarity consisted in the fact that one out of every twenty-five of its inhabitants was deaf. Two of the family who were its original settlers had been deaf; and this original leaven of affliction, like the veritable yeast plant itself, had gone on budding and sprouting and ramifying, until at the present day the whole town has a flavor of affliction; and, strange as it may seem, it is not only deafness (and dumbness) from which its quaint inhabitants suffer: some of them are blind, and some are idiotic. Dr. Bell has so many data in his possession that he has not had time as yet to thoroughly digest them all, but they strike him somewhat in this wise. All the way down and through one branch of an originally