On November 20, 1855, William Palmer went into a chemist's shop in Rugeley, in Staffordshire, and bought strychnine. His friend John Parsons Cook lay ill at the Talbot Arms across the road. A week earlier, at the Shrewsbury Handicap meeting, Cook had won three thousand pounds betting on a horse called Polestar, and since then, each time he drank or took something with Palmer, he had been violently sick. That night Cook died in convulsions so severe that his body arched off the bed. Palmer, who had taken charge of his treatment, got to the room so fast that one witness suspected he had been waiting up, fully dressed, for it to happen. He had by then collected Cook's winnings and forged his signature.
Palmer was born at Rugeley on August 6, 1824, qualified in medicine in London in 1846, and set up in practice in his home town, where he was by every account ruinously addicted to betting on horses. The deaths around him were extraordinary. His mother-in-law died at his house in 1849, having made him her heir. A creditor, Leonard Bladen, died there in 1850 with his betting book missing. Four of his five legitimate children died in infancy, their deaths put down to convulsions. His wife Ann died in 1854, soon after he insured her life for thirteen thousand pounds, and his brother Walter, also insured by him, died in 1855; the insurer questioned the policy and called for an inquiry into Walter's death. That June his housemaid, Eliza Tharme, gave birth to his illegitimate son. Cook, a sickly young man with an inherited fortune of twelve thousand pounds, was the next source of money.
The case against him was built on symptoms and purchases, because the poison itself was never found. Alfred Swaine Taylor, the leading toxicologist of the day, analyzed Cook's remains and detected no strychnine. He concluded from the pills Cook had been given that strychnine had killed him anyway, and told the court that the spasms Cook suffered could occur only with tetanus or strychnine; with tetanus ruled out, he inferred poison. Charles Newton, assistant to the chemist Salt, and Charles Roberts, apprentice at Hawkins's druggists, testified to selling Palmer strychnine, and the prosecution said he had swapped the pills prescribed by Cook's physician, Dr. Bamford, for pills of his own. The defense called experts to contradict Taylor and argued that Cook had died of a rare form of tetanus.
The inquest jury at Rugeley found that Cook had been murdered, even though the coroner summed up against it, and further inquests charged Palmer with the murders of Ann and Walter. His attorney then swore that he could not get a fair trial in Staffordshire. Parliament passed a special act, known afterward as Palmer's Act, allowing the trial to be moved to the Central Criminal Court in London, and it opened at the Old Bailey on May 14, 1856. It became the trial of the century, a courtroom battle between medical experts that brought chemical analysis into the English courts. On May 27 he was convicted of murdering Cook and sentenced to death. The indictments for his wife and brother were not proceeded with.
He was hanged outside Stafford prison on June 14, 1856, before a crowd of about thirty thousand. He never confessed. On the scaffold, by one account, he eyed the trapdoor and asked whether it was safe; by another his last words were that he was innocent of poisoning Cook by strychnine, a denial so exact that it has been argued over ever since. Charles Dickens called him the greatest villain that ever stood in the Old Bailey dock.