“Let me know if anything’s wrong,” he whispered, “or if I can do anything.  Wake me at once if you feel—­queer.”

He hardly knew what to say.  He lay down again, thinking and wondering what it all meant.  Defago, of course, had been crying in his sleep.  Some dream or other had afflicted him.  Yet never in his life would he forget that pitiful sound of sobbing, and the feeling that the whole awful wilderness of woods listened....

His own mind busied itself for a long time with the recent events, of which this took its mysterious place as one, and though his reason successfully argued away all unwelcome suggestions, a sensation of uneasiness remained, resisting ejection, very deep-seated—­peculiar beyond ordinary.

IV

But sleep, in the long run, proves greater than all emotions.  His thoughts soon wandered again; he lay there, warm as toast, exceedingly weary; the night soothed and comforted, blunting the edges of memory and alarm.  Half an hour later he was oblivious of everything in the outer world about him.

Yet sleep, in this case, was his great enemy, concealing all approaches, smothering the warning of his nerves.

As, sometimes, in a nightmare events crowd upon each other’s heels with a conviction of dreadfulest reality, yet some inconsistent detail accuses the whole display of incompleteness and disguise, so the events that now followed, though they actually happened, persuaded the mind somehow that the detail which could explain them had been overlooked in the confusion, and that therefore they were but partly true, the rest delusion.  At the back of the sleeper’s mind something remains awake, ready to let slip the judgment.  “All this is not quite real; when you wake up you’ll understand.”

And thus, in a way, it was with Simpson.  The events, not wholly inexplicable or incredible in themselves, yet remain for the man who saw and heard them a sequence of separate facts of cold horror, because the little piece that might have made the puzzle clear lay concealed or overlooked.

So far as he can recall, it was a violent movement, running downwards through the tent towards the door, that first woke him and made him aware that his companion was sitting bolt upright beside him—­quivering.  Hours must have passed, for it was the pale gleam of the dawn that revealed his outline against the canvas.  This time the man was not crying; he was quaking like a leaf; the trembling he felt plainly through the blankets down the entire length of his own body.  Defago had huddled down against him for protection, shrinking away from something that apparently concealed itself near the door flaps of the little tent.

Simpson thereupon called out in a loud voice some question or other—­in the first bewilderment of waking he does not remember exactly what—­and the man made no reply.  The atmosphere and feeling of true nightmare lay horribly about him, making movement and speech both difficult.  At first, indeed, he was not sure where he was—­whether in one of the earlier camps, or at home in his bed at Aberdeen.  The sense of confusion was very troubling.