ally slow and defective children up to a level of progress
which is normal to the average child, it will be wiser to take account of
the inequalities of children in original endowment and to differentiate
the course of study in such a way that each child will be allowed to
progress at the rate which is normal to him, whether that rate be rapid
or slow.

While we cannot hold all children to the same standard of school
progress, we can at least prevent the kind of retardation which involves
failure and the repetition of a school grade. It is well enough
recognized that children do not enter with very much zest upon school
work in which they have once failed. Failure crushes self-confidence and
destroys the spirit of work. It is a sad fact that a large proportion of
children in the schools are acquiring the habit of failure. The remedy,
of course, is to measure out the work for each child in proportion to
his mental ability.

Before an engineer constructs a railroad bridge or trestle, he studies
the materials to be used, and learns by means of tests exactly the
amount of strain per unit of size his materials will be able to
withstand. He does not work empirically, and count upon patching up the
mistakes which may later appear under the stress of actual use. The
educational engineer should emulate this example. Tests and forethought
must take the place of failure and patchwork. Our efforts have been too
long directed by "trial and error." It is time to leave off guessing and
to acquire a scientific knowledge of the material with which we have to
deal. When instruction must be repeated, it means that the school, as
well as the pupil, has failed.

Every child who fails in his school work or is in danger of failing
should be given a mental examination. The examination takes less than
one hour, and the result will contribute more to a real understanding of
the case than anything else that could be done. It is necessary to
determine whether a given child is unsuccessful in school because of
poor native ability, or because of poor instruction, lack of interest,
or some other removable cause.

It is not sufficient to establish any number of special classes, if they
are to be made the dumping-ground for all kinds of troublesome
cases--the feeble-minded, the physically defective, the merely backward,
the truants, the incorrigibles, etc. Without scientific diagnosis and
classification of these children the educational work of the