Permanent Blood Stains

Blubeard's blood stained key made me think of Lady Macbeth and her line "Out damn'd spot!" I tried to do some more research and see if this blood/guilt motif can be found in other pieces of literature but I didn't really find anything. I did however find reports of actual blood stains lasting for centuries...who know if this is fact or fiction? But it is interesting non-the-less

MURDER OF DAVID RIZZIO—PERMANENCY OF BLOOD-STAINS

On the evening of the 9th March 1565-6, David Rizzio, the Italian secretary of Mary of Scotland, was murdered in Holyrood Palace, by certain Protestant leaders of her court, with the assistance of her husband, Lord Darnley. The poor foreigner was torn from her side as she sat at supper, and dragged through her apartments to the outer door, where he was left on the floor for the night, dead with fifty-six wounds, each conspirator having been forced to give a stab, in order that all might be equally involved in guilt and consequent danger. The queen, who was then pregnant of her son (James I of England), deeply resented the outrage: indeed, there is reason to believe that it affected her so as to become the turning-point of her life, giving her in the first place a strong sense of the unworthiness of her husband, who perished less than a year after.

The floor at the outer door of the queen's apartments presents a large irregular dark mark, which the exhibitor of the palace states to be the blood of the unfortunate Rizzio. Most strangers hear with a smile of a blood-stain lasting three centuries, and Sir Walter Scott himself has made it the subject of a jocular passage in one of his tales, representing a Cockney traveller as trying to efface it with the patent scouring drops which it was his mission to introduce into use in Scotland. The scene between him and the old lady guardian of the palace is very amusing: but it may be remarked of Scott, that he entertained some beliefs in his secret bosom which his worldly wisdom and sense of the ludicrous led him occasionally to treat comically or with an appearance of scepticism. In another of his novels—the Abbot—he alludes with a feeling of awe and horror to the Rizzio blood-stain: and in his Tales of a Grandfather, he deliberately states that the floor at the head of the stair still bears visible marks of the blood of the unhappy victim. Joking apart, there is no necessity for disbelieving in the Holyrood blood-mark.

There is even some probability in its favour. In the first place, the floor is very ancient, manifestly much more so than the late floor of the neighbouring gallery, which dated from the reign of Charles II. It is in all likelihood the very floor which. Mary and her courtiers trod. In the second place, we know that the stain has been shewn there since a time long antecedent to that extreme modern curiosity regarding historical matters which might have induced an imposture: for it is alluded to by the son of Evelyn as being shewn in 1722. Finally, it is matter of experiment, and fully established, that wood not of the hardest kind (and it may be added, stone of a porous nature) takes on a permanent stain from blood, the oxide of iron contained in it sinking deep into the fibre, and proving indelible to all ordinary means of washing. Of course, if the wearing of a blood-stained, floor by the tread of feet were to be carried beyond the depth to which the blood had sunk, the stain would be obliterated. But it happens in the case of the Holyrood mark, that the two blotches of which it consisted are out of the line over which feet would chiefly pass in coming into or leaving the room. Indeed, that line appears to pass through and divide the stain,—a circumstance in no small degree favourable to its genuineness.

Alleged examples of blood-stains of old standing both upon wood and stone are reported from many places. We give a few extracted from the Notes and Queries. Amidst the horrors of the French Revolution, eighty priests were massacred in the chapel of the convent of the Camelites at Paris. The stains of blood are still to be seen on the walls and floor. 'At Cothele, a mansion on the banks of the Tamar, the marks are still visible of the blood spilt by the lord of the manor, when, for supposed treachery, he slew the warder of the drawbridge.' 'About fifty years ago, there was a dance at Kirton-in-Lindsey: (luring the evening a young girl broke a blood-vessel and expired in the room. I have been told that the marks of her blood are still to be seen. At the same town, about twenty years ago, an old man and his sister were murdered in an extremely brutal manner, and their cottage floor was deluged with blood, the stains of which are believed yet to remain.'

http://www.thebookofdays.com/months/feb/9.htm