Journal of John Winchester (Supernatural)

May 2

Sammy is two today. Two years in a row we’ve spent his birth-day in Colorado, where I had to stop by Daniel’s. Still never seen a vampire, but Elkins is such a hermit that because I talk to him, other hunters are starting to ask me to pick his brain for them.Crosses won’t repel them, and sunlight won’t kill them. They can go outside. They need blood to survive, and prefer human blood, but can survive on other mammals if there are no humans around. The only way to be sure of killing them is beheading—although the blood of a dead man is like poison to them. It won’t kill them, but it weakens them, makes them slow and sick.Daniel says they’re extinct, but he keeps an eye out anyway, and he thinks I should know enough about them to take one on if there are any left. He gave me a copy of this article, in case it was ever useful.

... the body of the brother last dead was according exhumed, and “living” blood being found in the heart and in circulation, it was cremated, and the sufferer began immediately to mend and stood before me a hale, hearty and vigorous man of fifty years.

From American Anthropologist, 1896