e insanities of the mind, and the convulsions of the muscles
described in the preceding genus, is curiously exact. The convulsions
without stupor, are either just sufficient to obliterate the pain, which
occasions them; or are succeeded by greater pain, as in the convulsio
dolorifica. So the exertions in the mania mutabilis are either just
sufficient to allay the pain which occasions them, and the patient dwells
comparatively in a quiet state; or those exertions excite painful ideas,
which are succeeded by furious discourses, or outrageous actions. The
studium inane, or reverie, resembles epilepsy, in which there is no
sensibility to the stimuli of external objects. Vigilia, or watchfulness,
may be compared to the general writhing of the body; which is just a
sufficient exertion to relieve the pain which occasions it. Erotomania may
be compared to trismus, or other muscular fixed spasm, without much
subsequent pain; and maeror to cramp of the muscles of the leg, or other
fixed spasm with subsequent pain. All these coincidences contribute to
shew, as explained in Sect. III. 5, that our ideas are motions of the
immediate organs of sense obeying the same laws as our muscular motions.

The violence of action accompanying insanity depends much on the education
of the person; those who have been proudly educated with unrestrained
passions, are liable to greater fury; and those, whose education has been
humble, to greater despondency. Where the delirious idea, above described,
produces pleasurable sensations, as in personal vanity or religious
enthusiasm; it is almost a pity to snatch them from their fool's paradise,
and reduce them again to the common lot of humanity; lest they should
complain of their cure, like the patient described in Horace,

--------Pol! me occidistis, amici,
Non servastis, ait, cui sic extorta voluptas,
Et demptus per vim mentis gratissimus error!

The disposition to insanity, as well as to convulsion, is believed to be
hereditary; and in consequence to be induced in those families from
slighter causes than in others. Convulsions have been shewn to have been
most frequently induced by pains owing to defect of stimulus, as the
shuddering from cold, and not from pains from excess of stimulus, which are
generally succeeded by inflammation. But insanities are on the contrary
generally induced by pains from excess of stimulus, as from the too violent
actions of our ideas, as in common anger, which is