What did Watson see? Why was he sent to see what was happening? Chapter -16

I think this should be in chapter 14. Watson sees an enormous hound, which does not look mortal at all. Fire bursts from its mouth and its body sparkles in the night. All three men are paralyzed by the savage sight.

Watson knew the place very well and so he was sent to see what was happening. He saw that Henry and Stapleton were talking over coffee and wine.