The Old Bookshop of Bordentown, New Jersey, has a single sheet for sale. Dated 1709, it carries the heading: 'Sanguis/Eating of blood forbidden', this - according to the seller - 'is a piece that encourages speculation as to origin and intent.'
The sheet is signed by Brook Taylor (1685-1731), an English mathematician famous for Taylor's theorem as well as Taylor series, known by those (like me) who have studied mathematics or physics. Taylor, however, according to Wikipedia also wroted an unfinished treatise On the Lawfulness of Eating Blood, and the sheet for sale is probably thematically related to that.
Whether the sheet is worth spending $350 on, or whether it is of use to anyone, is hard to say, but the Old Bookshop of Bordentown finds it 'an intriguing piece with its undercurrent vampire theme, connection to a famed mathematician, and "demonic" place name.'
Wikipedia, however, mentions another unfinished treatise by Taylor, On the Jewish Sacrifices, so I am afraid that the subject of the sheet is less of a mystery, as it is probably simply a discussion of Old Testament practices?
Far more expensive than Taylor's sheet is a note by Abraham Lincoln that is currently at sale here in Denmark. However, it is far less of a mystery than Taylor's manuscript, as Lincoln simply had this to say: 'I have not time to add a line intelligibly, I am terribly pressed to day. A. Lincoln. February 16, 1863.' The estimated value of this prosaic note is €4,000-5,000! But then, who knows, perhaps Lincoln was busy hunting vampires?