commonplace as the spectre of the Brocken,
and as natural. Was not Hobbes of Malmesbury
a great philosopher, who ought to know?
"We read," says Hobbes, "of Marcus Brutus
(one that had his life given him by Julius Cæsar,
and was also his favourite, and notwithstanding
murdered him) how at Philippi the night
before he gave battle to Augustus Cæsar he saw
a fearful apparition, which is commonly related
by historians as a vision; but considering the
circumstances, one may easily judge to have
been a short dream. For sitting in his tent
pensive and troubled with the horror of his rash
act, it was not hard for him, slumbering in the
cold, to dream of that which most affrighted
him; which fear, as by degrees it made him
awake, so also it must needs make the apparition
by degrees to vanish; and having no
assurance that he slept, he could have no cause to
think it a dream or anything but a vision."
Then there is moonshine. It makes many
things half visible, which timid folks interpret
into shapes of terror; burglars, perhaps, if their
fears are of the mundane sort; and if their taste
incline to the eerie, when the light is dim and
silence rules, they will know how to suspect,

       In every bush a hovering shade,
       A groan in every sound.

Moreover, there is hocus-pocus in its regular
commercial aspect, as it was abroad in the days
of the Egyptians, and as it is at home in these
present days. It is not difficult to understand
how the Egyptian priests showed visions on
their temple walls, or reflected pictures from
the surface of great bowls of water. The
devils shown by a conjuror to Benvenuto Cellini
were doubtless let loose from a magic lantern.
Some drugs give a man spectral illusions. A
conjuror offered Dr. Alderson a prescription
for a mixture of antimony, sulphur, and other
things, which should cause the person taking it
to be haunted by spectres.

A philosopher older than Hobbes, the poet
Lucretius, supposed that all ghosts were natural
productions, being merely thin pellicles cast off
from the body.

     Next, for 'tis time, my Muse declares and sings,

declares and sings through the medium of
Creech,

     What those are we call images of things,
     Which, like thin films, from bodies rise in streams,
     Play in the air, and dance upon the beams:
     By day these meet, and strike our minds and fright;
     And show pale ghosts and horrid shapes by night:
     These break our sleep, these check our gay delight,
     For sure no airy souls get loose, and fly
     From Hell's dark shades, nor flutter in our sky:
     For what remains, beyond the greedy Urn,
     Since soul and body to their seeds return?
     A stream of forms from every surface flows,
     Which may be called the film or shell of those:
     Because they bear the shape, they show the frame
     And figure of the bodies whence they came.

About the middle of the seventeenth century
the doctrine of Palingenesis prevailed. This
was a chemical explanation of the theory of
Lucretius. It asserted that if a flower were
burnt and pulverised, a salt might be obtained
which was the essential part of the flower; that
on mixing this substance with something which
was not disclosed, and applying heat, a spectral
flower would arise, corresponding to that
which was burnt. This was explained by
supposing that the particles of the salt, when
heated, attracted one another, and flew off into
the respective places they had occupied when
in the living plant, so that they thus formed a
shadowy representation of it. That being taken
for an established fact, it was easy enough to
apply it to the human body, which, when
fermenting underground, threw off such particles
of the essential salt to rise into the air, be
drawn into their old relative positions, and thus
form

                 horrid apparitions tall and ghastly,
     To walk at dead of night, or take their stand
     O'er some new-opened grave.

But why the winding-sheet threw off this
salt, and not the coffin—for the ghosts always
came up dressed in their grave-clothes, never
cased in their coffins—Palingenesists have not
explained.

Another theory, metaphysical, not chemical,
made Fancy an incomprehensible material thing
lodged in the middle lobe of the brain, which
acts the part of a servant to the mind in
arranging together the different material ideas
brought to the brain by its other servants. The
over-zealous industry of this servant in working
after the others were gone to bed, was supposed
to produce the appearance of spectres, which
were thus taken to be, in a very literal sense,
the workings of Fancy.

Now we come to the unwholesome class—
the natural ghosts; ideas made unusually vivid
by some morbid condition of the mind or body.
Ghosts of this kind are as natural as those of the
other class. Ideas are copies of sensations, only
less intense. If any unhealthy excitement adds
to the intensity, they may be indistinguishable
from impressions of things actually seen and
heard. The writer of this, having seen a large
number of ghosts, and heard many ghostly voices
in his childhood and youth, has, as a wise man
once put it, seen too many ghosts to believe in
them. And yet how clear and distinct they
were. A long flaming sword, for example, in
the air at noonday over London, at the time of
the cholera visitation of 'thirty-one, or
thereabouts; and not only a flaming sword, but
the clouds arranged in a frame about it to
bring out the picture, as they certainly were
not really arranged in the sky. Bah! the
pattern of the sword was that chosen by the
artist of the first illustrated edition of Paradise
Lost, whose pictures were often pored over by
the young natural-ghost-seer; and it was a
shape reflecting little credit on the genius of
the heavenly swordsmiths, if they have
swordsmiths in heaven.

Take the third experiment of Sir Humphrey
Davy in an atmosphere of nitrous oxide. He
says, "A thrilling, extending from the chest
to the extremities, was almost immediately
produced. I felt a sense of tangible extension,
highly pleasurable, in every limb; my visible
impressions were dazzling, and apparently
magnified. I heard distinctly every sound in the
room, and was perfectly aware of my situation.