A faint stench came from the aperture as the doctor unclosed it, and I fancied his pounding elicited a kind of low, hissing response. Finally he motioned me to replace him at the peep-hole, and I did so with a causeless and increasing tremor. The barred, ground- glass window, close to the earth outside, admitted only a feeble and uncertain pallor; and I had to look into the malodorous den for several seconds before I could see what was crawling and wriggling about on the straw-covered floor, emitting every now and then a weak and vacuous hiss. Then the shadowed outlines began to take shape, and I perceived that the squirming entity bore some remote resemblance to a human form laid flat on its belly. I clutched at the door-handle for support as I tried to keep from fainting.