suppose that he is about fifteen months old and in good bodily
condition. If he is older, the same tests would be used to begin with,
though we could at once pass on to more complicated and difficult ones
that cannot as yet be used with the fifteen-months-old baby.

First, with regard to sight. We wish to know if he can distinguish
reasonably small objects at reasonable distances; whether he can see
moderately small things at short distances; whether the angle of his
vision is normal. In other words, whether his range and angle of vision
are sufficient for all ordinary purposes.

If he can recognize his father or mother or brothers and sisters at a
distance of a hundred feet he can see far enough for all practical
purposes. If he readily finds a small object like a pin or a small black
bead when dropped on the floor, his sight is sharp enough at short range
to serve his purposes. If his attention can be attracted by waving a
hand or a little flag or a flower fifty or sixty degrees on either side
of the direction in which he is looking, that is, two-thirds of the way
to the side of his head, his angle of vision is sufficiently wide. If he
can pick out from seven balls of worsted of the seven primary
colors--red, orange, yellow, green, blue, indigo, and violet--the ball
that matches another of the same color, he is at least not color-blind
and has a sufficient sense of color for the ordinary purposes of life.
It may be necessary to wait till eighteen months for a satisfactory
color test. Color blindness, when present, is usually most apparent in a
failure to distinguish between red and green, these two widely differing
colors seeming to produce the same impression upon the color-blind eye.
The child will be just as likely to choose a red ball to match the green
one in his hand as to select another red ball. But repeated tests should
be made before accepting color blindness as a fact, since sometimes the