Hermann Cohn

“ Every one knows that legibility is improved by contrast; the darker the print and the clearer the paper, so much easier is the reading. When the lines are close together, or the matter is printed "solid," the eyes become tired sooner, because the contrast is lessened. The lines tend to run together, and the effort to separate them strains the eyes. ”

“ All three kinds of eyes may become far-sighted or old-sighted as their near vision becomes weaker in old age. This kind of far-sightedness is no more a disease than the turning gray of the hair; it depends upon the diminished force of the muscle that curves the crystalline lens for near vision. ”

“ The thickness of the strokes should also be regarded, for it is obvious that the form of the letter is more readily and more clearly impressed on the retina when the stroke is broad and distinct than when it is fine. Letters having a stroke of less than one fourth of a millimetre (1/100 of an inch) , in thickness should not be admitted into school-books. Ample space should be allowed between the letters. Laboulaye recommended that every two letter should be separated by a clear space at least as broad as the distance between the two strokes of the n. ”

“ All agree likewise that it arises from a too steady application of the eyes to close objects, especially during the school age. The attention of the authorities in Baden was directed to this fact forty years ago, by the number of students in the gymnasia who wore spectacles. Their inquiries were followed up by Dr. Szokalsky in Paris. Professor C. von Jäger, of Vienna, in 1861, was the first person who made a systematic examination of the eyes of children in reference to this point. Out of two hundred children, he found fifty-five per cent. of those in an orphan house, and eighty per cent. ”

“ The number of short-sighted scholars rises regularly from the lowest to the highest classes in all institutions; 3. The average degree of myopy increases from class to class—that is, the short-sighted become more so. ”

“ Short-sightedness hardly exists in the village schools—the number of cases increases steadily with the increasing demands which the schools make upon the eyes, and reaches the highest point in the gymnasia ”

“ Loring and Derby observed in New York, in 1876, that fourteen per cent. of the children of Irish, twenty per cent. of American, and twenty-four per cent. of German parents, were near-sighted. At the International Congress of Physicians, held in Paris in 1867, I confidently addressed every one who wore spectacles in German, and was sure to receive a German answer. It is possible that the Germans have become more than ordinarily predisposed to short-sightedness, by the operation of compulsory education through several generations ”