ision of
good and wholesome food for the children of the poor may be rendered
necessary. But much of the physical evil results from improper
nutrition; and here the school agencies may do a great deal in the
future by furthering the teaching of domestic science to the girls of
the working classes. Such teaching, however, if it is to be effective,
must be real and must take into account the actual conditions under
which their future lives are to be spent. At the present time much of
the teaching is valueless, through its neglect of the actual income and
resources of the working man's home.

The second condition necessary for bodily growth and development is a
sufficiency of pure air. This is necessary, since the oxygen of the air
is not only the active agent in the maintenance of life, but is also
requisite for the combustion of the foodstuffs conveyed into the body.
Much has been done within recent years in our schools to provide
well-ventilated classrooms and to instruct teachers how to keep the air
of the school pure. Here again the problem is to a large extent a social
one, involving the better housing of our great town population.

A third condition necessary for the physical development of the child is
sleep sufficient in quantity and good in quality. The weak, puny
children in arms to be seen in our crowded slums owe their condition, in
many cases, to the want of sound sleep, to the fact that they never are
allowed to rest, as much as to the under and improper feeding to which
they are subjected. As we shall see in the next chapter, much might be
done by the establishment of Free Kindergarten Schools in our
overcrowded districts to alleviate the lot and to better the education
of the very young children of the poor.

But in addition to the three conditions already named, which may be
classed together as the nutritive factors in bodily growth, there is a
fourth condition essential for all development, whether bodily or
mental--viz., exercise. For "development is produced by exercise of
function, use of faculty.... If we wish to develop the hand, we must
exercise the hand. If we wish to develop the body, we must exercise the
body. If we wish to develop the mind, we must exercise the mind. If we
wish to develop the whole human being, we must exercise the whole human
being."[25]

But any form of exercise will not do. The exercise which is given must
be given at the right time, must be in harmony with the nature of