After having treated in a separate dissertation on the matter of the apparitions of angels, demons, and disembodied souls, the connection of the subject invites me to speak also of the ghosts and excommunicated persons, whom, it is said, the earth rejects from her bosom; of the vampires of Hungary, Silesia, Bohemia, Moravia, and Poland; and of the vroucolacas of Greece. I shall report first of all, what has been said and written of them; then I shall deduce some consequences, and bring forward the reasons or arguments that may be adduced for, and against, their existence and reality. The _revenans_ of Hungary, or vampires, which form the principal object of this dissertation, are men who have been dead a considerable time, sometimes more, sometimes less; who leave their tombs, and come and disturb the living, sucking their blood, appearing to them, making a racket at their doors, and in their houses, and lastly, often causing their death. They are named vampires, or oupires, which signifies, they say, in Sclavonic, a leech. The only way to be delivered from their haunting, is to disinter them, cut off their head, impale them, burn them, or pierce their heart. Several systems have been propounded to explain the return, and these apparitions of the vampires. Some persons have denied and rejected them as chimerical, and as an effect of the prepossession and ignorance of the people of those countries, where they are said to come back or return. Others have thought that these people were not really dead, but that they had been interred alive, and returned naturally to themselves, and came out of their tombs. Others believe that these people are very truly dead, but that God, by a particular permission, or command, permits or commands them to come back to earth, and resume for a time their own body; for when they are exhumed, their bodies are found entire, their blood vermilion and fluid, and their limbs supple and pliable. Others maintain that it is the demon who causes these _revenans_ to appear, and by their means does all the harm he occasions both men and animals.