encountered Miss Michell; or she did you!" He smiled
humorously. "While your feelings were excited by the unusual episode,
the strange surroundings and the dark, she related to you a wild legend
of witchcraft and monsters. Later, when you suffered your first attack
of marsh-gas poisoning, your consequent hallucination took form from the
story you had just heard. Later conversations with your mysterious lady
fixed the idea into an obsession. Recurrent dreams are a common
phenomenon even in healthy persons. In this case, no doubt the exact
repetition of the physical sensations of miasmic poisoning tended to
reproduce in your mind the same sequence of ideas or semi-delirious
imaginings. These were of course varied or distorted somewhat on each
occasion, influenced by what you had been hearing or reading in advance
of them. This mental condition became more and more confirmed as you
steeped yourself more deeply in legendary lore and also--pardon me--in
the morbid fancies of the young lady; whose ghostly visits in the dark
and whose increasing interest for you put a further bias upon your
thoughts."

"What were the noises I heard from the lake, and the shocks we all
felt?" I demanded.

He nodded amiably toward Vere.

"Mr. Vere has mentioned the large bubbles which formed and burst on the
surface of the lake. That is a common manifestation of ordinary marsh
gas. Possibly the singular and unknown emanation that took place at
night came to the surface in the form of a bubble or bubbles huge enough
to produce in bursting the smacking sound of which you speak. But I am
inclined to another theory, after a walk I took about your place this
morning. When you put up your cement dam instead of the old log affair
that held back only a part of the stream, you made a greater depth and
bulk of water in the swamp basin than it has contained these many years,
if ever. As a result, I believe the sloping mud basin began to slip
toward the dam. Oh, very gradually! Probably not stirring for weeks at a
time. Just a yielding here, a parting there, until the cloudburst
precipitated the disaster. You had, my dear Roger, a miniature
landslide, which would account for sounds of shifting mud and water in
your lake, and for the shocks or trembling of your house when the earth
movements occurred."

The rest of us regarded one another. I think Vere might have spoken, if
he had not been unwilling to mar Phillida's contentment by any
appearance of dis