Gases Released by Corpse to Reveal Invisible Ink
The interesting history of invisible ink can be dated back over 2,000 years ago starting with the ancient Greeks and Romans. The first known record comes from Pliny the Elder in his book “Natural History” by using the milk of the tithymalus plant to create the invisible ink. These inks have consisted of various ingredients, including urine, vinegar, lemons, diluted blood, and saliva. The intrigue and mystery of these hidden inks still capture our attention today.
Invisible inks were mainly used during wars to conceal messages from foes. The Revolutionary War, which lasted from 1775 to 1783, saw an increase in the use of invisible inks on both the British and American side. Riding on the coattails of the war’s many successful invisible ink concoctions came a clever idea to use the ink as a way of indicating whether the presumed dead were truly dead. The concept seemed almost magical.
By using acetate of lead to create an ink, the phrase “I am really dead” was written on a piece of paper. The paper was then placed under the corpse’s nose. The body’s release of sulfur dioxide, the consequence of putrefaction, would activate the ink. If “I am really dead” appeared on the paper, the corpse was officially decided dead.
False positives were an occasional problem. Dentistry, as it is known today, did not exist. Common problems like tooth decay and tonsillitis would also cause the emission of sulfur dioxide leading the infamous ink to test positively for one’s death. Although invisible ink tests were as fascinating as they were cunning, its unreliability ultimately led to its abandonment for other more dependable means of testing.