retty well illustrated among
ourselves when we contrast the sexes. A girl develops in body and mind
rapidly, and ceases to grow comparatively early. A boy's bodily and
mental development is slower, and his growth greater. At the age when
the one is mature, finished, and having all faculties in full play, the
other, whose vital energies have been more directed towards increase of
size, is relatively incomplete in structure; and shows it in a
comparative awkwardness, bodily and mental. Now this law is true of each
separate part of the organism, as well as of the whole. The abnormally
rapid advance of any organ in respect of structure, involves premature
arrest of its growth; and this happens with the organ of the mind as
certainly as with any other organ. The brain, which during early years
is relatively large in mass but imperfect in structure, will, if
required to perform its functions with undue activity, undergo a
structural advance greater than is appropriate to its age; but the
ultimate effect will be a falling short of the size and power that would
else have been attained. And this is a part-cause--probably the chief
cause--why precocious children, and youths who up to a certain time were
carrying all before them, so often stop short and disappoint the high
hopes of their parents.

But these results of over-education, disastrous as they are, are perhaps
less disastrous than the effects produced on the health--the undermined
constitution, the enfeebled energies, the morbid feelings. Recent
discoveries in physiology have shown how immense is the influence of the
brain over the functions of the body. Digestion, circulation, and
through these all other organic processes, are profoundly affected by
cerebral excitement. Whoever has seen repeated, as we have, the
experiment first performed by Weber, showing the consequence of
irritating the _vagus_ nerve, which connects the brain with the
viscera--whoever has seen the action of the heart suddenly arrested by
irritating this nerve; slowly recommencing when the irritation is
suspended; and again arrested the moment it is renewed; will have a
vivid conception of the depressing influence which an over-wrought brain
exercises on the body. The effects thus physiologically explained, are
indeed exemplified in ordinary experience. There is no one but has felt
the palpitation accompanying hope, fear, anger, joy--no one but has
observed how laboured becomes the action of the heart