ion was exerted on the organ of sense; and then even
common stimuli were sometimes perceived: for her mind was so strenuously
employed in pursuing its own trains of voluntary or sensitive ideas, that
no common stimuli could so far excite her attention as to disunite them;
that is, the quantity of volition or of sensation already existing was
greater than any, which could be produced in consequence of common degrees
of stimulation. But the few stimuli of the tuberose, and of the tea, which
she did perceive, were such, as accidentally coincided with the trains of
thought, which were passing in her mind; and hence did not disunite those
trains, and create surprise. And their being perceived at all was owing to
the power of volition preceding or coinciding with that of irritation.

This explication is countenanced by a fact mentioned concerning a
somnambulist in the Lausanne Transactions, who sometimes opened his eyes
for a short time to examine, where he was, or where his ink-pot stood, and
then shut them again, dipping his pen into the pot every now and then, and
writing on, but never opening his eyes afterwards, although he wrote on
from line to line regularly, and corrected some errors of the pen, or in
spelling: so much easier was it to him to refer to his ideas of the
positions of things, than to his perceptions of them.

7. The associated motions persisted in their usual channel, as appeared by
the combinations of her ideas, and the use of her muscles, and the equality
of her pulse; for the natural motions of the arterial system, though
originally excited like other motions by stimulus, seem in part to continue
by their association with each other. As the heart of a viper pulsates long
after it is cut out of the body, and removed from the stimulus of the
blood.

8. In the section on sleep, it was observed that the nerves of sense are
equally alive and susceptible to irritation in that state, as when we are
awake; but that they are secluded from stimulating objects, or rendered
unfit to receive them: but in complete reverie the reverse happens, the
immediate organs of sense are exposed to their usual stimuli; but are
either not excited into action at all, or not into so great action, as to
produce attention or sensation.

The total forgetfulness of what passes in reveries; and the surprise on
recovering from them, are explained in Section XVIII. 19. and in Section
XVII. 3. 7.

9. It appears from hence, that reveri