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"So if there was no real reason to do an autopsy, no obvious reason, poisoning could easily be mistaken for a disease and escape notice. But that was changing around 1915. Forensic toxicology had improved and there was something called the Marsh test. And this test and some other confirmation procedures allowed investigators to detect even really small amounts of arsenic in tissue and body fluids. And that set a scientific standard that was accepted as evidence in court. It was considered pretty reliable."