uction and derangement may come easily, through the
stress laid upon vision in the person's mental economy. I need not
enlarge upon the different forms of special defect which come through
impairment of sight by central lesion or degeneration of the visual
centers and connections. Suffice it to say that they are very common,
and very difficult of recovery. The visual person is often so
completely a slave to his sight that when that fails either in itself
or through weakness of attention he becomes a wreck off the shore of
the ocean of intellect. When we consider the large proportion just
mentioned of pupils of this type, the care which should be exercised
by the school authorities in the matter of favourable conditions of
light, avoidance of visual fatigue, proper distance-adjustments in all
visual application as regards focus, symmetry, size of objects,
copies, prints, etc., becomes at once sufficiently evident to the
thoughtful teacher, as it should be still earlier to the parent. There
should be a medical examination, by a competent oculist, before the
child goes to school, and regular tests afterward. School examiners
and boards should have qualifications for reporting on the hygienic
conditions of the school as regards lighting. The bright glare of a
neighbouring wall before a window toward which children with weak eyes
face when at their desks may result not only in common defects of
vision but also in resulting mental and moral damage; and the results
are worse to those who depend mainly on vision for the food, drink,
and exercise, so to speak, of their growing minds.

As to the methods of teaching these and also the other sensory pupils,
the indications already given must suffice. The statement of some of
these far-reaching problems of educational psychology, and of the
directions in which their answers are to be sought, exhausts the
purpose of this chapter. In general it may be said that the
recommendations made for the treatment of sensory children at the
earlier stage may be extended to later periods also, and that the
treatment should be, for the most part, in intelligent contrast to
that which the motor pupils receive.

_Language Study._--From this general consideration of the child's
training it becomes evident that the great subjects which are most
useful for discipline in the period of secondary education are the
mathematical studies on the one hand, which exercise the faculty of
abstraction, and the p