What was that loathsome red dew that gleamed, wet and glistening, on one of the hands, as though the canvas had sweated blood? How horrible it was! – more horrible, it seemed to him for the moment, than the silent thing that he knew was stretched across the table, the thing whose grotesque, misshapen shadow on the spotted carpet showed him that it had not stirred, but was still there, as he had left it.

– Oscar Wilde

The Picture of Dorian Gray, Chapter 14. When Dorian goes to cover the portrait after stabbing Basil to death he notices that it has undergone a dramatic new change in appearance. He experiences a feeling of terror when he sees the "red dew" glistening on one of the hands, as if the painting had "sweated blood" and is alive. He finds the sight more horrifying than that of Basil’s corpse after he murdered him. The evidence of Dorian’s diabolical crime is clearly portrayed in the portrait.