Far away on the path we saw Sir Henry looking back, his face white in the moonlight, his hands raised in horror, glaring helplessly at the frightful thing which was hunting him down. But that cry of pain from the hound had blown all our fears to the winds. If he was vulnerable he was mortal, and if we could wound him we could kill him. Never have I seen a man run as Holmes ran that night.

The Complete Sherlock Holmes (ed. 1930)