The New York Times

In the 1870s, the Rev. Herbert H. Hayden, a married father and minister of a Methodist church in Rockland, Conn., was accused of poisoning his mistress, a young servant girl, whom he believed he'd gotten pregnant. At Hayden's trial, which captured national attention, four professors testified to the presence of arsenic in the girl's body. It was identical to an ounce of the element that Hayden had purchased from a drugstore—to get rid of rats around his house, he said—just hours before the murder. Hayden's attorneys managed to cloud the prosecution's case by repeatedly challenging the professors' statements, and they persistently declined to swear that there was absolutely no doubt about their findings. He got off on a hung jury.

The Reverend Herbert H. Hayden (1850-1907)

In September 1878, the Minister of the Methodist Church in Rockland, Connecticut,  enticed a young servant girl, Mary Stannard, to a lonely spot where he gave her a drink consisting of a ounce (28 g) of arsenic in a cup of water telling her it would cause an abortion - he believed he had made her pregnant. When she started screaming in agony he knocked her unconscius with a blow to the head and then slit her throat.

In October the following year his trial for murder lasted 15 weeks and God-fearing Americans where enthralled by it. Particularly noteworthy were the extent of the forensic evidence and the disreputable attempt of the defence lawyers to find alternative explanations for the amount of arsenic found in Mary's body.

Mary Stannard came from a poor family. She worked as a servant and those who knew her found her cheerful and hard-working, but then she was 19 she had an illegitimate child, Willie, by a man whose name she never revealed.

In 1878 she was employed by the 29-year-old Reverend Hayden and his wife Rosa. They had two chindren and were expecting a third. Hayden was attracted to Mary, nor did she rebuff his advances, with the consequence that on 20 March 1878, they slipped away from the parish oyster supper and had a furtive sexual encounter. Mary thought that it resulted in her becoming pregnant and she confided in her sister that the man responsible for her condition was the minister. She said she would confront him and ask him to arrange for her to have an abortion.

On Monday, 2 September she managed to see Hayden alone in his barn and he promised to get her some 'medicine' that would bring this about. The following day he left for Middletown although he told his wife he was going to Durham to buy some oats.  He gave himself a reason for visiting Middletown by first calling for a man who was making him some tools.

Then he went to Tyler's Drigstore where he purchased an ounce of arsenic for ten cents, saying he wanted to get rid of rats that were a problem around his house. The poison was wrapped up and clearly labelled and its sale, but nor its purchaser, was entered in the sale book.

Somewhat unluckily, as Hayden left the drugstore he was accosted by a man who knew him, and they spoke of the imminent birth of Hayden's third child. On his way back to Rockland, Hayden called at the Stannard house ostensibly to ask for a drink of water, but really to speak to Mary and tell her that he had obtained the 'medicine' and would meet her that afternoon at the Big Rock which was well away from prying eyes.

When he got home he transferred the arsenic to an old spice tin and disposed of the packaging. Soon after his midday meal he left home, telling his wife that hewas going to stack woodat the woodlot he owned.

He arrived at the Big Rock at 2.30, where Mary was awaiting, and there he dissolved the whole ounce (28 000 mg) in water and persuaded her to drink it all down. By 3 p.m. she knew something was wrong and 3.15 she was screaming in agony and starting to run home. Hayden grabbed a chunk of wood and with two heavy blows he knocked her unconscius. Then, thinking to make her death appear to be suicide, he took out his jacknife and slit her throat. He arranged her body in a peaceful pose, her hat under her head, so that it appeared as if she had deliberately lain down to die.

Of course he dare not leave his knife at the scene of the crime and his plan now was to go home and return later with another knife. He then ran to the woodlot, stacked a few logs to show that he had been there that afternoon, and went home, where he washed his jacknife and placed it out of sigh on a high shelf.

Unfortunately for the minister, his plan began to unfold when Mary's body was discovered by a member of her family who went to look for her, worried that she had not returned home after a heavy downpour late that afternoon.

On Wednesday, 4 September the Reverend Hayden rose early and went to the woodlot where he spent a couple of hours stacking wood and loading his wagon in an attempt to make it appear that he had spent most of the previous afternoon gainfully employed. Then he returned home and finding neighbours visiting his wife he made a point of asking for his jacknife and 'finding' it on a high shelf in the kitchen.

Meanwhile at the Stannard house an autopsy had been performed on Mary's body which revealed that she had not been pregnant but was suffering from an ovarian cyst.  The doctor who performed it did not search for evidence that she had died of poisoning because that was not suspected. At the inquest Hayden was accused of her murder by Mary's sister and he was arrestd the following day.

On Tuesday, 10 September Herbert Hayden appeared before the Justice Court,  which was held in the basement of the Congregational Church in nearby Madison. After a two-week trial it decided that he was innocent of the charge of murdering Mary Stannard and he left court to the cheers of a large group of supporters.

All this was somewhat premature because so far nothing had been said about Mary having taken a large dose of arsenic, but Professor Samuel Johnson of Yale Medical College was about to remedy this defect in the evidence. When he did, and when it was realized that Hayden has been to Middletown to purchase arsenic the day Mary died, it became imperative to issue a new warrant for the minister's arrest, which was done on 8 October.

He was brought to trial a year later, by which time Mary's body had been twice disinterred for a further samples to be taken for arsenic tests to be carried out.

The Hayden tial aroused interest across the USA and became known as 'The Great Case'. The forensic evidence against him was damning and indeed was of a much higher standard that normal. Not only Professor Johnson of Yale but his colleague Professor Edward Dana took the stand on behalf of the prosecution.

Dana had even travelled to England to the Devon Great Consols mine to obtain samples of arsenic, this being the sole source of arsenic that was sold throughout the USA. He did this because he had discovered that it was possibly to identify a particular batch of arsenic trioxide by examinig its crystals under a microscope.

At the mine he learned that the material could be so identified despite the crystals being ground up before being bagged and shipped.  The reason was that the tiniest crystals were unaffected by the grinding and their shape did indeed vary from batch to batch.

Dana's evidence indicated that the arsenic in Mary's stomach was the same as that from the drugstore in Middletown and different from the ounce of arsenic in the spice tin that was eventually handed over to the Court. (It was never discovered who replaced the missing arsenic although it would have been easy for Hayden to buy more arsenic anywhere in the state during the two weeks before he was re-arrested.)

Dana was correctly able to identify different samples of arsenic crystals when he was presented with them in ramdon order, and without being told where they were from. He and Johnson had of course performed the Marsh test on all samples that they had obtained. Two other professors also provided more forensic evidence of arsenic in the organs taken from Mary's body.

However, it was the sheer amount and novelty of the forensic evidence, which allowed the defence counsel to so confuse the jury by endlessly challenging it that the jurors appear to have ignored it when reaching their verdict. The defence even maintained that the large amount of arsenic found in Mary's stomach had been planted there deliberately to incriminate the Reverend Hayden.

The quantities discovered in the body were exceedingly large: 23 grains (1500 mg) were extracted from her liver, which is where most of that which had been absorbed through the stomach wall had ended up, although some had penetrated to her lungs and brain.

When it was challenged by the defence that this what not possible in the short time that she had lived, further evidence proved that it was possible. (The learned professor took small doses of arsenic and showed that it could be detected in their urine whitin 15 minutes.) When it was sggested that the arsenic in her brain could have diffused there from the stomach as her body lay in the grave, tests on other cadavers were carried out to show this did not happen.

What perhaps persuaded the jury to disregard the scientific evidence was the defence's deliberate questioning of every statement made by the professors,  who were always reluctant to swear that there was absolutely no doubt about their findings. More telling was rhe fact that Mary was no pregnant - thereby removing the motive the minister had for murdering her.

Most telling of all was the tearful and emotional performance that his wife Rosa gave in the witness box, which reduce many in the court to tears as she showed complete faith in her husband's innocence even to the extent of lying for him about his movements taht day.

Finally, on 14 January 1880, the jury retired to consider its verdict. We know from the voting slips which they discarded that originally they voted 10-to-2 for not guilty, then the following day it was 11-to-1, but even after another nine ballots they never achieved the  necessary 12-to-0 for an acquital. A plucky farmer, David Hotchkiss, was not to be browbeaten by the other members of the jury, and of course he was right.

It was a hung jury, and that would mean another trial, but knowing how the jury had voted meant that the state was not prepared to finance another long drawn out prosecution that would be likely to fail. The Reverend Herbert Hayden walked free. The family moved to New Haven where he worked as a carpenter and shop assistant. He died of liver cancer when he was 57.

The Elements of Murder by John Emsley