ces the origin of dreams to previous sensations. "The dreams of
sleeping men," says this profound philosopher, "are all made up of the
waking man's ideas, though for the most part oddly put together."[85] And
Dr. Hartley, who explains all the phenomena of the imagination by his
theory of vibrations and associations, says, that dreams are nothing but
the imaginations or reveries of sleeping men, and that they are
deducible from three causes--viz, the impressions and ideas lately
received, and particularly those of the preceding day, the state of the
body, more especially of the stomach and brain, and association.[86]

Macrobius mentions five sorts of dreams. 1st. vision--2nd. a discovery
of something between sleeping and waking--3rd. a suggestion cast into
our fancy, called by Cicero, _visum_,--4th. an ordinary dream--and
fifth, a divine apparition or revelation in our sleep; such as were the
dreams of the prophets, and of Joseph, as also of the Eastern Magi.

CAUSE OF DREAMS.

Avicen makes the cause of dreams to be an ultimate intelligence moving
the moon in the midst of that light with which the fancies of men are
illuminated while they sleep. Aristotle refers the cause of them to
common sense, but placed in the fancy. Averroes, an Arabian physician,
places it in the imagination; Democritus ascribes it to little images,
or representations, separated from the things themselves; Plato among
the specific and concrete notions of the soul; Albertus to the superior
influences, which continually flow from the sky, through many specific
channels.

Some physicians attribute the cause of dreams to vapours and humours,
and the affections and cares of persons predominant when awake; for, say
they, by reason of the abundance of vapours, which are exhaled in
consequence of immoderate feeding, the brain is so stuffed by it, that
monsters and strange chimera are formed, of which the most inordinate
eaters and drinkers furnish us with sufficient instances. Some dreams,
they assert, are governed partly by the temperature of the body, and
partly by the humour which mostly abounds in it; to which may be added
the apprehensions which have preceded the day before; and which are
often remarked in dogs, and other animals, which bark and make a noise
in their sleep. Dreams, they observe, proceed from the humours and
temperature of the body; we see the choleric dreams of fire, combats,
yellow colours, etc. the phlegmatic of water baths, of