The History of Invisible Ink

Sources say between 1822 and 1845, 465,000 people were taken to these waiting mortuaries and not one of them woke up from their deaths. One way that was actually used to determine if someone was really dead is to use invisible ink made of acetate lead. They would then place this piece of paper under the dead person's nose on their face. The gases emitted after death while rotting would activate the invisible ink and boom. Now they know they have a dead person. All of a sudden, I am really dead would come onto the paper.

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