mental exertion. Great care should be taken that the head is not
subjected to injury of any kind, as it is almost invariably accompanied
by some nervous derangement. Exposure to extreme heat should be
carefully avoided. An attack of sun-stroke although it may not be
immediately fatal, may occasion tumors in the brain, or some organic
disease.


SLEEP.


For all animated beings sleep is an imperious necessity, as
indispensable as food. The welfare of man requires alternate periods of
activity and repose. It is a well-established physiological fact, that
during the wakeful hours the vital energies are being expended, the
powers of life diminished, and, if wakefulness is continued beyond a
certain limit, the system becomes enfeebled and death is the result.
During sleep there is a temporary cessation of vital expenditures, and a
recuperation of all the forces. Under the influence of sleep "the blood
is refreshed, the brain recruited, physical sufferings are extinguished,
mental troubles are removed, the organism is relieved, and hope returns
to the heart."

The severest punishment which can be inflicted upon a person, is to
entirely deprive him of sleep. In China, a few years since, three
criminals were sentenced to be kept awake until they should die. To do
this it was necessary to keep a guard over them. The sentinels were
armed with sharp, pointed instruments, with which to goad the victims
and thus prevent them from sleeping. Life soon became a burden, and,
although they were well fed during the time, death occurred sooner than