then produced, but by imagination alone, as I have myself frequently
experienced; in this case the idea of biting a china cup, when I imagine it
very distinctly, or when I see another person bite a cup or glass, excites
an actual pain in the nerves of my teeth. So that this idea and pain seem
to be nothing more than the reiterated motions of those nerves, that were
formerly so disagreeably affected.

Other ideas that are excited by imagination or recollection in many
instances produce similar effects on the constitution, as our perceptions
had formerly produced, and are therefore undoubtedly a repetition of the
same motions. A story which the celebrated Baron Van Swieton relates of
himself is to this purpose. He was present when the putrid carcase of a
dead dog exploded with prodigious stench; and some years afterwards,
accidentally riding along the same road, he was thrown into the same
sickness and vomiting by the idea of the stench, as he had before
experienced from the perception of it.

4. Where the organ of sense is totally destroyed, the ideas which were
received by that organ seem to perish along with it, as well as the power
of perception. Of this a satisfactory instance has fallen under my
observation. A gentleman about sixty years of age had been totally deaf for
near thirty years: he appeared to be a man of good understanding, and
amused himself with reading, and by conversing either by the use of the
pen, or by signs made with his fingers, to represent letters. I observed
that he had so far forgot the pronunciation of the language, that when he
attempted to speak, none of his words had distinct articulation, though his
relations could sometimes understand his meaning. But, which is much to the
point, he assured me, that in his dreams he always imagined that people
conversed with him by signs or writing, and never that he heard any one
speak to him. From hence it appears, that with the perceptions of sounds he