precursors of the graver mischief which finally falls upon the
nerve-centres if the lighter warnings have been neglected; and for this
reason no man who has to use his brain energetically and for long
periods can afford to disregard the hints which he gets from attacks of
palpitation of heart or from a disordered stomach. In many instances
these are the only expressions of the fact that he is abusing the
machinery of mind or body; and the sufferer may think himself fortunate
that this is the case, since even the least serious degrees of direct
exhaustion of the centres with which he feels and thinks are more grave
and are less open to ready relief.

When affections of the outlying organs are neglected, and even in many
cases where these have not suffered at all, we are apt to witness, as a
result of too prolonged anxiety combined with business cares, or even of
mere overwork alone, with want of proper physical habits as to exercise,
amusement, and diet, that form of disorder of which I have already
spoken as cerebral exhaustion; and before closing this paper I am
tempted to describe briefly the symptoms which warn of its approach or
tell of its complete possession of the unhappy victim. Why it should be
so difficult of relief is hard to comprehend, until we remember that the
brain is apt to go on doing its weary work automatically and despite the
will of the unlucky owner; so that it gets no thorough rest, and is in
the hapless position of a broken limb which is expected to knit while
still in use. Where physical overwork has worn out the spinal or motor
centres, it is, on the other hand, easy to enforce repose, and so to
place them in the best condition for repair. This was often and happily
illustrated during the late war. Severe marches, bad food, and other
causes which make war exhausting, were constantly in action, until
certain men were doing their work with too small a margin of
reserve-power. Then came such a crisis as the last days of McClellan's
retreat to the James River, or the forced march of the Sixth Army Corps
to Gettysburg, and at once these men succumbed with palsy of the legs. A
few months of absolute rest, good diet, ale, fresh beef and vegetables
restored them to perfect health.

In all probability incessant use of a part flushes with blood the
nerve-centres which furnish it with motor energy, so that excessive work
may bring about a state of congestion, owing to which the nerve-centre
becomes bad