e. A parity of reasoning shews, that a few
sober generations may gradually in the same manner restore a due degree of
irritability to the family, and decrease the excess of sensibility.

From hence it would appear probable, that scrophula and dropsy are diseases
from inirritability; but that in epilepsy and insanity an excess of
sensibility is added, and the two faulty temperaments are thus conjoined.

SPECIES.

1. _Mania mutabilis._ Mutable madness. Where the patients are liable to
mistake ideas of sensation for those from irritation, that is, imaginations
for realities, if cured of one source of insanity, they are liable in a few
months to find another source in some new mistaken or imaginary idea, and
to act from this new idea. The idea belongs to delirium, when it is an
imaginary or mistaken one; but it is the voluntary actions exerted in
consequence of this mistaken idea, which constitute insanity.

In this disease the patient is liable carefully to conceal the object of
his desire or aversion. But a constant inordinate suspicion of all people,
and a carelessness of cleanliness, and of decency, are generally
concomitants of madness. Their designs cannot be counteracted, till you can
investigate the delirious idea or object of their insanity; but as they are
generally timid, they are therefore less to be dreaded.

Z. Z. called a young girl, one of his maid-servants, into the parlour, and,
with cocked pistols in his hands, ordered her to strip herself naked; he
then inspected her with some attention, and dismissed her untouched. Then
he stripped two of his male servants in the same manner, to the great
terror of the neighbourhood. After he was secured, with much difficulty he
was persuaded to tell me, that he had got the itch, and had examined some
of his servants to find out from whom he had received it; though at the
same time there was not a spot to be seen on his hands, or other parts. The
outrages in consequence of this false idea were in some measure to be
ascribed to the pride occasioned by unrestrained education, affluent
wealth, and dignified family.

Madness is sometimes produced by bodily pain, particularly I believe of a
diseased liver, like convulsion and epilepsy; at other times it is caused
by very painful ideas occasioned by external circumstances, as of grief or
disappointment; but the most frequent cause of insanity arises from the
pain of some imaginary or mistaken idea; which may be termed hal