Play has been called the ideal type of exercise, because it is the
kind of exercise that occupies the whole child, his mental as well
as his physical side--and later, also, the moral side. In play the
exercise is regulated by the interests, so that, while there may be
extreme exertion, there is not the same danger of overstrain as is
possible with work that he is forced to do. In play the exercise is
carried on with freedom of the spirit, so that the flow of blood and
the feeling of exhilaration make for health.

When children begin to play at work their activities are not
entirely imitative, although the kind of work they choose will be
determined by the kinds of activities that go on about them. The
child has real interests in work; and these should be encouraged and
cultivated. The chief interest is, perhaps, the growing sense of
mastery over the materials which the child uses. He can make blocks
take on any form he pleases; although the first houses he tries to
build are apt to be just a random piling of his material, there
follows a growing deliberation and planning, so that he comes at
last to make what he has _intended_ to make, and not merely
produce an accidental result.

The earlier plays of the child are not at all in the nature of
games; there is not at first the need for a companion. There is no
special order in which the various acts of his play have to be
carried out. When he plays horse on a stick, or is a parade all by
himself, or plays house in the corner, a few simple movements are
repeated until the child is tired of them, or until something occurs
to shift his interest. Nor is there in these early plays a special
point that marks the end of the interest. In games, however, these