Macduff was listening now, listening with all that uncanny perception which lurks in the eardrums of a thoroughbred dog. He whined softly under his breath at what he heard. And he trembled to dash in the direction of the sound. But Vail’s mandate held him where he was.
Presently a new sense allied itself to his hearing. His miraculously keen nostrils flashed to his brain the presence of an odor which would have been imperceptible to any human but which carried its own unmistakable meaning to the thoroughbred collie.
Perhaps, too, there came to him, as sometimes to dogs, a strange perception that was neither sound nor smell nor sight—something no psychologist has ever explained, but which every close student of dogs can verify.
The trembling changed to a shudder. Up went Macduff’s pointed muzzle, skyward. From his shaggy throat issued an unearthly wolf-howl.
Again and again that weird scream rang through the house; banishing sleep and reëchoing in hideous cadences from every nook and corner and rafter. A hundredfold more compelling than any mere fanfare of barking, it shrieked an alarm to every slumbering brain.
In through the open front doorway from the veranda rushed Thaxton Vail.
“Mac!” he cried. “Shut up! What’s the matter?”
For answer the collie danced frantically, peering up the stairway and then beseechingly back at Vail. No dogman could have failed to interpret the plea.
“All right,” vouchsafed Thaxton. “Go!”
Like a furry whirlwind the dog scurried up the stairs into the regions of the house which had been so silent but whence now came the murmur of startledly questioning voices and the slamming of doors.