ne_.

This is easily accounted for. Uneducated persons, who are deprived of
one or more of the senses, are isolated from the world in which they
live. The book of nature is open before them, but they are unable to
peruse it. The simplest operations constantly going on around them are
locked in mystery. They are an enigma to themselves. Even those who are
endowed with inquisitive minds are perplexed with the existing state of
things. They know nothing of the physical organization of the planet we
inhabit, of its political and civil divisions, and of the whole
machinery of human society, and are profoundly ignorant of the past
history and future destiny of the race to which they belong. It is not
remarkable that mind so unnaturally and peculiarly circumstanced--with
its usual inlets of knowledge so obstructed, and deprived of external
objects to act upon--should prey upon itself, and thus superinduce
insanity in its usual forms, and more especially when unaided and
undirected by education.

Keeping the same principle in view, we shall not be surprised to find
that _want of exercise_ of the brain and nervous system, or, in other
words, that inactivity of intellect and feeling, is a very frequent
predisposing cause of every form of nervous disease, even with those who
have not been deprived of any of their senses. For demonstrative
evidence of this position, we have only to look at the numerous victims
to be found among females of the middle and higher ranks, who have no
call to exertion in gaining the means of subsistence, and no objects of
interest on which to exercise their mental faculties, and who
consequently sink into a state of mental sloth and nervous weakness,
which not only deprives them of much enjoyment, but subjects them to
suffering, both of body and mind, from the slightest causes.

In looking abroad upon society, we find innumerable examples of mental
and nervous debility from this cause. When a person of some mental
capacity is confined for a long time to an unvarying round of
employment, which affords neither scope nor stimulus for one half of his
faculties, and, from want of education or society, has no external
resources, his mental powers, for want of exercise to keep up due
vitality in their cerebral organs, become blunted, and his perceptions
slow and dull. Unusual subjects of thought become to him disagreeable
and painful. The intellect and feelings not being provided with
interests external to t