es nine weary weeks,
and never visited by sleep night or day; of the drop of poisonous foam
that forms on the moon, and, falling to earth, is collected for
pernicious ends; of the sweltering venom of the toad, the finger of the
babe killed at its birth by its own mother, the tricklings from the
murderer's gibbet. In Nature, again, something is felt to be at work,
sympathetic with human guilt and supernatural malice. She labours with
portents.

Lamentings heard in the air, strange screams of death,
And prophesying with accents terrible,

burst from her. The owl clamours all through the night; Duncan's horses
devour each other in frenzy; the dawn comes, but no light with it.
Common sights and sounds, the crying of crickets, the croak of the
raven, the light thickening after sunset, the home-coming of the rooks,
are all ominous. Then, as if to deepen these impressions, Shakespeare
has concentrated attention on the obscurer regions of man's being, on
phenomena which make it seem that he is in the power of secret forces
lurking below, and independent of his consciousness and will: such as
the relapse of Macbeth from conversation into a reverie, during which he
gazes fascinated at the image of murder drawing closer and closer; the
writing on his face of strange things he never meant to show; the
pressure of imagination heightening into illusion, like the vision of a
dagger in the air, at first bright, then suddenly splashed with blood,
or the sound of a voice that cried 'Sleep no more' and would not be
silenced.[196] To these are added other, and constant, allusions to
sleep, man's strange half-conscious life; to the misery of its
withholding; to the terrible dreams of remorse; to the cursed thoughts
from which Banquo is free by day, but which tempt him in his sleep: and
again to abnormal disturbances of sleep; in the two men, of whom one
during the murder of Duncan laughed in his sleep, and the other raised a
cry of murder; and in Lady Macbeth, who rises to re-enact in
somnambulism those scenes the memory of which is pushing her on to
madness or suicide. All this has one effect, to excite supernatural
alarm and, even more, a dread of the presence of evil not only in its
recognised seat but all through and around our mysterious nature.
Perhaps there is no other work equal to _Macbeth_ in the production of
this effect.[197]

It is enhanced--to take a last point--by the use of a literary
expedient. Not even in _Ri