e same organs. Now, it is a principle of nature
that while the organs of an animal system are in process of formation and
growth, they can exercise their power only for a very brief period at a
time without exhaustion. This necessitates on the part of all young animals
incessant changes of action, or alternations of action and repose. A farmer
of forty years of age, whose organs are well developed and mature, will
chop wood all day without excessive fatigue. Then, when he comes home at
night, he will sit for three hours in the evening upon the settle by his
fireside, _thinking_--his mind occupied, perhaps, upon the details of the
management of his farm, or upon his plans for the following day. The vital
force thus expends itself for many successive hours through his muscles,
and then, while his muscles are at rest, it finds its egress for several
other hours through the brain. But in the _child_ the mode of action must
change every few minutes. He is made tired with five minutes' labor. He
is satisfied with five minutes' rest. He will ride his rocking-horse, if
alone, a short time, and then he comes to you to ask you to tell him a
story. While listening to the story, his muscles are resting, and the force
is spending its strength in working the mechanism of the brain. If you make
your story too long, the brain, in turn, becomes fatigued, and he feels
instinctively impelled to divert the vital force again into muscular
action.

If, instead of being alone with his rocking-horse, he has company there,
he will _seem_ to continue his bodily effort a long time; but he does not
really do so, for he stops continually, to talk with his companion, thus
allowing his muscles to rest for a brief period, during which the vital
force expends its strength in carrying on trains of thought and emotion
through the brain.

He is not to be blamed for this seeming capriciousness. These frequent
changes in the mode of action are a necessity, and this necessity evidently
unfits him for any kind of monotonous or continued exertion--the only kind
which, in ordinary cases, can be made conducive to any useful results.

3. Parents at home and teachers at school must recognize these
physiological laws, relating to the action of the young, and make their
plans and arrangements conform to them. The periods of confinement to any
one mode of action in the very young, and especially mental action, must
be short; and they must alternate frequently with o