“I am being followed,” he said to himself.  “I am being followed, and by some utterly abominable person.”

He went by the Chapel, and struck across to the right, not looking behind him, but analyzing his feelings.  Being strongly intuitive, he had no need to turn his head.  He knew now for certain the cause of his uneasiness.  Some dreadful human being was very near to him, full of hateful thoughts, sinister recollections, possibly evil intentions.  Something, the very vibrations of the night air, it might be, carried, as a telegraph wire conveys a message, the soul-aroma of this human being to the doctor.  As he walked on, not hurrying, he mutely diagnosed the heart of this unseen being.  It seemed full of deadly disease.  Never had he suspected man or woman of such wickedness as he divined here; never had he felt from any of his kind such a sick repulsion as from this unseen monster who was journeying steadily in his steps.  Doctor Levillier was puzzled at the depth of the horror which beleaguered him.  He remembered once driving a staid, well-behaved horse in a country lane.  The animal ambled forward at a gentle pace, flicking its ears lazily to circumvent the flies, apparently at ease with its driver and with the world.  But suddenly it raised its head, drew the air into its distended nostrils, stopped, quivered in every limb, and then, with a strange cry, bolted like a mad thing.  Far away a travelling menagerie was encamping.  It had scented the wild animals.

Doctor Levillier felt like that horse.  A longing to bolt for his life came upon him.  He had an impulse to cry out, to run forward, to escape out of the atmosphere created by this evil nature, this deadly life.  He could have crept like a coward into the shadow of one of the areas of Henrietta Street, and sheltered there till the thing went past.  And, just because he had this almost overmastering desire to flee, he stood still, paused abruptly, and, without turning his head, listened.  At a distance, and he judged, round the corner of the street he heard the sound of a quickening footstep advancing in his direction.  He waited, under the obligation of exerting all his powers of self-control; for his limbs trembled to movement, his heart beat to the march, and every separate vein, every separate hair of his body, seemed crying out piercingly to begone.  The footstep approached.  Doctor Levillier heard it turning the corner.

“Now,” thought he, “this person will see me waiting here.  Will he come on?  Will he pass me?  And if he does, shall I be able to await, to endure the incident?”

And he listened, as a scout might listen in the night for sounds of the hidden enemy.  Upon turning the corner, the footsteps advanced a pace or two, faltered, slackened, stopped.  For an instant there was silence.  The doctor knew that the man had been struck by his attentive figure, and was pausing to regard it, to consider it.  What would be the result of the inspection?  In a moment the doctor knew.  The footsteps sounded again, this time in retreat.