In March 1699, the body of Sarah Stout, a young Quaker woman, was found floating in the Priory Mill dam in Hertford, England. Suspicion immediately fell upon Spencer Cowper, a married lawyer and member of a prominent Whig political family, who had visited her home shortly before her death. Stout's family alleged that Cowper had strangled her to secure a financial debt and dumped her body into the water.
When the trial commenced at the Hertford Assizes, it evolved into one of the earliest high-profile battles of forensic science in legal history. The central evidentiary debate revolved around a bizarre physical question: whether a body that drowns alive sinks, whereas a body thrown into water post-mortem floats. Medical prosecution witnesses argued that a living person swallows water upon drowning, making the corpse heavy enough to sink to the bottom, whereas a dead body dumped in water retains air in the lungs and floats immediately.
The defense countered by calling renowned medical figures, including Dr. Samuel Garth, who debunked this myth by testifying that water entry dynamics and lung capacity vary wildly, and that floating depends largely on putrefaction and body weight rather than whether death occurred before or after immersion. Ultimately, the lack of physical marks of violence on Stout's body and Cowper's solid alibi led to his acquittal, but the trial marked a crucial moment in forensic history, exposing the deep divide between folk medical beliefs and emerging anatomical science.