In the French quarter of New Orleans, John Edgar Browning is about to take part in a "feeding". It begins as clinically as a medical procedure. His acquaintance first swabs a small patch on Browning’s upper back with alcohol. He then punctures it with a disposable hobby scalpel, and squeezes until the blood starts flowing. Lowering his lips to the wound, Browning's associate now starts lapping up the wine-dark liquid. “He drank it a few times, then cleaned and bandaged me,” Browning says today.

To Browning’s bemusement, he was not quite to his host’s taste. “He said my blood was not as metallic as it should have been – so he was a little disappointed,” he recalls; apparently, diet, hydration and blood group can all make a subtle difference to the flavour. After they had cleaned up, the pair went to a charity dinner in aid of the homeless.

A self-confessed “needle-phobe”, Browning had not been looking forward to the feeding. “I’m actually pretty fearful of anything sharp approaching my skin,” he says. But as a researcher at Louisiana State University, he was willing to go through with it for his latest project: an ethnographic study of the New Orleans “real vampire” community.