In the middle of that night Hamel sat up in bed, awakened with a sudden start by some sound, only the faintest echo of which remained in his consciousness.

His nerves were tingling with a sense of excitement.

He sat up in bed and listened.

Suddenly it came again--a long, low moan of pain, stifled at the end as though repressed by some outside agency.

He leaped from his bed, hurried on a few clothes, and stepped out on to the landing.