of which varies in degree when compared with other individuals. For
example, Evelyn has about the same capacity for physical work as
Annie, but she stands lower than the latter in arithmetic and higher
in language work. John shows about the same physical power as Henry,
when measured by running and jumping and chinning; but John can hit
the ball with his bat more times out of a hundred than Henry can,
whereas Henry can hit the bull's-eye with his rifle more times out
of a hundred than John can. In a thousand details any two children
differ from each other, one excelling in nearly half of the points,
the other excelling perhaps in about as many, and the two standing
almost exactly alike in some matters.

A child that excels most of his colleagues in one or a few points is
said to have marked ability in that direction--as the exceptional
athlete, or the child with exceptional literary or moral feeling. On
the other hand, a child that seems to measure well up to the average
in most points, and even to excel in a few, may fall far short in
some matters,--that is, may be deficient. Thus a perfectly good
child in every other way may be unable to master the ordinary
requirements in arithmetic, or a child may have an entirely
satisfactory development in every way and be deficient in musical
discrimination.

Another kind of difference is to be found in what may be called
general capacity. Some children show higher capacity than the
average along nearly every line that can be measured or tested,
without showing a preponderance in any one direction. Such children
are said to be of high grade, or of high "vitality." In the same way
many children are below the average in nearly every line, without
being particularly defective along any one line. They can do one