Page:Popular Science Monthly Volume 70.djvu/417

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HEN we pass along the streets of our cities and large towns and observe the number of persons between the ages of twenty and forty who wear spectacles; or again, if we inspect the eyesight of the children of our public schools and of the young people in our colleges, we find that a large proportion of the present generation is afflicted with visual organs more or less defective. More than this, there is hardly a person over fifty who does not use some sort of artificial aid to sight. In the German universities the situation is still worse. There, apparently, almost one half of the students wear eye-glasses. England furnishes a marked contrast; spectacles on the eyes of young men and young women are far less common. The chief reason doubtless is the fondness of both sexes for outdoor life. It is highly probable that our somewhat abnormal eyesight is chiefly due to the abnormal conditions under which we live. The epithet abnormal is of course to be understood in a relative sense; it is not strictly applicable to a highly developed stage of civilization. It can not properly be said that the conditions under which the Papuans or the Bushmen live are more natural than those of the residents of London or New York. Each generation is, in a sense, weaker but also wiser; what is lost in one direction is more than made up in another. Still, the injudicious use of the eyes in artificial light and a short range of vision seem to be inevitably imposed upon the dwellers in cities. It is a well-established fact in hygiene that any bodily organ is strengthened by the wise use of it. This being the case, it follows that persons who spend much of their time out-of-doors and in looking at objects afar off, or who use their eyes but little after nightfall, will retain their sight unimpaired much longer than do most people of the present day. On the other hand, failing vision is the natural concomitant of advancing age, so that the number of persons beyond sixty who see clearly with the naked eye is exceedingly small and probably was never very large.

Moreover, the human eye is said to be a rather ill-contrived piece of mechanism. A celebrated German physicist is reported to have remarked that if an artisan were to make for him a piece of apparatus so poorly adapted to its purpose he would not accept it. Biographers have, however, preserved the names of a considerable number of persons from the remote and more recent past whose mental faculties were unimpaired at fourscore and beyond, though it is not often that this could be affirmed of their sight. The last chapter of Deuteronomy