A Primer on Forensic Science

Aug 13, 2012 - by Liz Porter

Aug. 13, 2012

Skulls on the beach of Punuk Island Alaska

Skulls on the beach of Punuk Island Alaska

by Liz Porter

The science

Many experts start their forensic science timeline in 1810, when a German scientist did a chemical test for a particular ink dye on a document. Three years later, Spaniard Mathieu Orfila published his Toxicologie Générale, as a result of which he is usually regarded as the father of modern toxicology.

In 1835, Londoner Henry Goddard, a member of the Bow Street Runners, the unofficial police force set up by the writer and magistrate Henry Fielding, initiated the use of bullet comparison when investigating a burglary. He spotted a flaw in a bullet lodged in a bed’s backboard, matching it both to other bullets in the suspect’s gun and to the mould from which the bullets had been made. This enabled him to solve the crime. The butler did it, then invented a story about a masked intruder to cover up his own “inside job.”

In the following year, English chemist James Marsh, inventor of a method to measure small amounts of arsenic ingested or absorbed by a human body, used the technique in the trial of a man accused of poisoning his grandfather. But the jury, confused by the complexity of Marsh’s testimony, acquitted the man. As a result, the scientist improved and simplified his method into a technique that was easier to explain to lay people, devising a test for arsenic in dead bodies which became known as the Marsh Test.

In 1850, French physician Marcel Bergeret was able to exonerate a couple accused of killing a baby whose mummified remains had been unearthed while they were renovating their apartment. Workmen removing brickwork behind the mantelpiece had discovered the remains. Bergeret carried out an autopsy on the body, finding some moths and larvae from a flesh fly on it. Using his knowledge of the succession of insects that visit dead bodies, he calculated that the moths had grown from eggs laid in 1849, meaning that the flies must have laid their eggs on the newly dead body in 1848, when it was walled in, before the current occupants had moved into the apartment. Suspicion was then directed at previous occupants, specifically a young woman who had appeared at one point to be pregnant but had never been seen with a baby. She was arrested and tried for murder but was acquitted because the cause of her baby’s death could not be established.

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