Over and over again we repeated it, using different articles, pieces of which I was certain she didn’t know the name.  There was a strange bond between the gem and the intelligence, some strange force emanating from its lustre.  On myself it was depressing; on the dog it was life itself.  At last Jerome had an inspiration.

“Try the Rhamda,” he said; “think of him.  Perhaps—­”

It was most surprising.  Certainly it was remarkable.  It was too much like intelligence; a bit too uncanny.  At the instant of the thought the dog leaped backward.

Such a strange transformation; she was naturally gentle.  In one instant she had gone mad.  Mad?  Not in the literal interpretation; but figuratively.  She sprang back, snapping; her teeth bared, her hair bristled.  Her nostrils drawn.  With one bound she leaped between the curtains.

Jerome jumped up.  With an exclamation he drew the portieres.  I was behind him.  The dog was standing at the edge of the room, bristling.

The room was empty.  What did she see?  What?

One thing was certain.  Though we were sure of nothing else we were certain of the Rhamda.  We could trust the canine’s instinct.  Every previous experiment we had essayed had been crowned with success.  We had here a fact but no explanation.  If we could only put things together and extract the law.

It was late when we retired.  I could not sleep.  The restlessness of the dog held back my slumber.  She would growl sullenly, then stir about for a new position; she was never quite still.  I could picture her there in the library, behind the curtains, crouched, half resting, half slumbering, always watching.  I would awaken in the night and listen; a low guttural warning, a sullen whine—­then stillness.  It was the same with my companion.  We could never quite understand it.  Perhaps we were a bit afraid.

But one can become accustomed to almost anything.  It went on for many nights without anything happening, until one night.

It was dark, exceedingly dark, with neither moon nor starlight; one of those nights of inky intenseness.  I cannot say just exactly what woke me.  The house was strangely silent and still; the air seemed stretched and laden.  It was summer.  Perhaps it was the heat.  I only knew that I woke suddenly and blinked in the darkness.

In the next room with the door open I could hear the heavy breathing of the detective.  A heavy feeling lay against my heart.  I had grown accustomed to dread and isolation; but this was different.  Perhaps it was premonition.  I do not know.  And yet I was terribly sleepy; I remember that.

I struck a match and looked at my watch on the bureau—­twelve thirty-five.  No sound—­not even Queen—­not even a rumble from the streets.  I lay back and dropped into slumber.  Just as I drifted off to sleep I had a blurring fancy of sound, guttural, whining, fearful—­then suddenly drifting into incoherent rumbling phantasms—­a dream.  I awoke suddenly.  Someone was speaking.  It was Jerome.