health became more
and more impaired.

At length, when he was almost worn out, having spent the greater part of
many nights reading instead of sleeping, in order to avoid the
frightful visions, he happened to mention his insufferable condition to
Osdeven. Far from ridiculing his rival, Osdeven, with great earnestness,
encouraged him to relate everything that had happened to him in his
sleep; and when Nielsen had done so, exclaimed, "I'll tell you what it
is--these dreams you have are not ordinary nightmares; they are due to a
mara--I know their type well."

"To a mara!" Nielsen cried; "how ridiculous! Why not say to a
mise--or--grim? It would be equally sensible; they are all idle
superstitions."

"So you say now," Osdeven rejoined, "but wait! When you get into bed
to-night, lie on your back, and in your right hand hold a sharp knife on
your breast, the point upwards. Remain in this attitude from between
eleven o'clock till two, and see what happens."

Nielsen laughed, but all the same decided to do as Osdeven suggested.
Night came, and, knife in hand, he lay in his bed.

Minutes passed, and nothing happening, he was beginning to think what a
fool he was for wasting his time thus, when suddenly he perceived
bending over him the luminous figure of a beautiful nude woman, whom, to
his utter astonishment, he identified as Christine Jansen--Christine
Jansen in all but expression. The expression in the eyes he now looked
into was not human--it was hellish. The figure got on the bed and was
in the act of sitting astride him, when it came in contact with the
knife. Then it uttered a frightful scream of baffled rage and pain, and
vanished.

Nielsen, shaking with terror and dreading another visitation, struck a
light. The point of his knife was dripping with blood.

An hour later, overcome with weariness, he fell asleep, and for the
first time for weeks his slumber was sound and undisturbed. Awaking in
the morning much refreshed, he would have attributed his experience to
imagination or to a dream, had it not been for the spots of blood on the
bedclothes and the stains on his knife, and this evidence, as to the
reality of what had happened, was strengthened by his discovery of
certain circumstances in connexion with Miss Jansen, towards whom his
sentiments had now undergone a complete change.

Curious to learn if anything had befallen her, he made cautious
inquiries, and was informed that owing to a sudden indispositi