s latter
experiment might throw some light upon the much debated question of
formal discipline. In all these cases the teacher must be on his guard
not to accept as universal principles what he has found to be true of a
small group of pupils, until at least he has found his conclusions
verified by other experimenters.

=C. Direct Questions.=--This method involves the submission of questions
to pupils of a particular age or grade, collecting and classifying their
answers, and basing conclusions upon these. Much work in this direction
has been done in recent years by certain educators, and much
illuminating and more or less useful material has been collected. A good
deal of light has been thrown upon the apperceptive material that
children have possession of by noting their answers to such questions
as: "Have you ever seen the stars? A robin? A pig? Where does milk come
from? Where do potatoes come from?" etc., etc. The practical value of
this method lies in the insight it gives into the interests of children,
the kind of imagery they use, and the relationships they have set up
among their ideas. Every teacher has been surprised at times at the
absurd answers given by children. These absurdities are usually due to
the teacher's taking for granted that the pupils have possession of
certain old knowledge that is actually absent. The moral of such
occurrences is that he should examine very carefully what "mind stuff"
the pupils have for interpreting the new material.

=D. Biographical Studies of Individual Children.=--Many books have been
written describing the development of individual children. These
descriptions doubtless contain much that is typical of all children, but
one must be careful not to argue too much from an individual case. Such
records are valuable as confirmatory evidence of what has already been
observed in connection with other children, or as suggestive of what may
be looked for in them.

PERIODS OF DEVELOPMENT

The period covered by child study may be roughly divided into three
parts, namely, (1) infancy, extending from birth to three years of age,
(2) childhood, from three to twelve, and (3) adolescence, from twelve to
eighteen. While children during each of these periods exhibit striking
dissimilarities one from another, there are nevertheless many
characteristics that are fairly universal during each period.

1. INFANCY

=A. Physical Characteristics.=--One of the striking features of infan