Donders remarked this difference between his private patients—representing the wealthy and cultivated class—and his hospital patients: that while over-sight was distributed between the two classes in nearly equal proportion, near-sight occurred much more frequently among his private patients.
The investigations of Dr. Peter A. Callan belong in this category, with a qualification. He examined the sight of 457 colored-school pupils, aged from five to nineteen years, of the New York public schools, Nos. 3 and 4, and he found but 2.6 per cent, of them near-sighted. This field was selected because it was thought to furnish the nearest approach to the normal eye to be found in this locality. The Southern freedmen, he thinks, would afford the best possible field for this special line of investigation. As a class, the colored people of New York, prior to this generation, had very limited educational advantages, and the occupations which tax the sight, like engraving, etc., have never been known among them. But as these 457 subjects are now receiving the best school-training that the city affords, the superior condition of their sight must be referred to their freedom from hereditary tendency to myopia. The conscientious painstaking and thoroughness of Dr. Callan's work, as exhibited in his report, are manifest and noteworthy.
The uniform drift of results in all the examinations here referred to, and relating to over 26,000 individuals, may be regarded as sufficiently establishing the following propositions:
1. That, as a rule, near-sight originates in school-life.
2. That a large percentage of the scholars are thus afflicted—the percentage progressing with the stage of advancement in study.
3. That near-sight is progressive in degree, according to the length of school-experience.
But, though the demonstration of these points is now complete, further and successive examinations will still be useful to determine the improvement consequent upon the adoption of means to that end, and to furnish a standard of comparison between different schools in respect to material or methods, or both—that is, first, in respect to arrangement of building, amount and direction of light, character and position of desks, seats, etc.; and, second, in respect to methods of teaching, especially in the earlier years, and generally to the intelligent observance and enforcement by the teachers of hygienic conditions. Dr. Howe's report is interesting in this feature, showing that "in schools where the hygienic conditions relating to the position of the pupils and the amount of light are disregarded, the proportion of near-sighted pupils grows larger; and conversely, where these relations are observed, the number diminishes;" and he gives