Wade Davis, a Canadian ethnobotanist (someone who studies what effect plants have on people), wrote about zombies in two books, The Serpent and the Rainbow (1985) and (1988). Davis went to Haiti in 1982 and wrote about how a living person can be turned into a zombie by two special powders being rubbed into a wound. The first powder brings a 'deathlike' state because of a certain poison in it, called tetrodotoxin (the same deadly poison found in the Japanese blowfish). At just the right amount, it can make a person almost die, but not quite. The second powder puts the person in a zombie-like state where they seem to have no free will of their own.