of activity even to the point of fatigue, without injury--as,
_e.g._, the lungs in talking while all the other members are at rest.
But, on the other hand, it is not well to talk and run at the same time.

The idea that the body may be preserved in a healthy state longer by
sparing it--_i.e._, by inactivity--is an error which springs from a
false and mechanical conception of life. It is just as foolish to
imagine that health depends on the abundance and excellence of food, for
without the power of assimilating the food taken, nourishment of
whatever kind does more harm than good; all real strength develops from
activity alone.

Sec. 56. Physical education, according as it relates to the repairing, the
muscular, or the emotional activities, is divided into (1) diatetics,
(2) gymnastics, (3) sexual education. In the direct activity of life
these all interact with each other, but for our purposes we are obliged
to speak of them as if they worked independently. Moreover, in the
development of the human being, they come into maturity of development
in a certain order: nutrition, muscular growth, sexual maturity. But
Pedagogics can treat of these only as they are found in the infant, the
child, and the youth; for with the arrival of mature life, education is
over.

FIRST CHAPTER.

_Diatetics._

Sec. 57. By diatetics we mean the art of repairing the constant waste of
the system, and, in childhood, of also building it up to its full form
and size. Since in reality each organism has its own way of doing this,
the diatetical practice must vary somewhat with sex, age, temperament,
occupation, and circumstances. The science of Pedagogics has then, in
this department, only to enunciate general principles. If we go into
details, we fall into triviality. Nothing can be of more importance for
the whole life than the way in which the physical education is managed
in the very first stages of development. So generally is this fact
accepted, that almost every nation has its own distinct system, which
has been carefully elaborated. Many of these systems, no doubt, are
characterized by gross errors, and widely differ as to time, place, and
character, and yet they all have a justification for their peculiar
form.

Sec. 58. The best food for the infant in the first months of its life is
its mother's milk. The employment of another nurse, if a general custom,
as in France, is highly objectionable, since with the milk the child is
l