Returning to his cabin late at night with a deer on his shoulders Charles Marlowe tried the door.  It did not yield.  He knocked; there was no answer.  He laid down his deer and went round to the window.  As he turned the angle of the building he fancied he heard a sound as of stealthy footfalls and a rustling in the undergrowth of the forest, but they were too slight for certainty, even to his practised ear.  Approaching the window, and to his surprise finding it open, he threw his leg over the sill and entered.  All was darkness and silence.  He groped his way to the fire-place, struck a match and lit a candle.

Then he looked about.  Cowering on the floor against a wall was his wife, clasping his child.  As he sprang toward her she rose and broke into laughter, long, loud, and mechanical, devoid of gladness and devoid of sense—­the laughter that is not out of keeping with the clanking of a chain.  Hardly knowing what he did he extended his arms.  She laid the babe in them.  It was dead—­pressed to death in its mother’s embrace.

III

THE THEORY OF THE DEFENSE

That is what occurred during a night in a forest, but not all of it did Irene Marlowe relate to Jenner Brading; not all of it was known to her.  When she had concluded the sun was below the horizon and the long summer twilight had begun to deepen in the hollows of the land.  For some moments Brading was silent, expecting the narrative to be carried forward to some definite connection with the conversation introducing it; but the narrator was as silent as he, her face averted, her hands clasping and unclasping themselves as they lay in her lap, with a singular suggestion of an activity independent of her will.

“It is a sad, a terrible story,” said Brading at last, “but I do not understand.  You call Charles Marlowe father; that I know.  That he is old before his time, broken by some great sorrow, I have seen, or thought I saw.  But, pardon me, you said that you—­that you—­”

“That I am insane,” said the girl, without a movement of head or body.

“But, Irene, you say—­please, dear, do not look away from me—­you say that the child was dead, not demented.”

“Yes, that one—­I am the second.  I was born three months after that night, my mother being mercifully permitted to lay down her life in giving me mine.”

Brading was again silent; he was a trifle dazed and could not at once think of the right thing to say.  Her face was still turned away.  In his embarrassment he reached impulsively toward the hands that lay closing and unclosing in her lap, but something—­he could not have said what—­ restrained him.  He then remembered, vaguely, that he had never altogether cared to take her hand.

“Is it likely,” she resumed, “that a person born under such circumstances is like others—­is what you call sane?”

Brading did not reply; he was preoccupied with a new thought that was taking shape in his mind—­what a scientist would have called an hypothesis; a detective, a theory.  It might throw an added light, albeit a lurid one, upon such doubt of her sanity as her own assertion had not dispelled.