by Val McDermid
Mysterious cases often need imagination to bring them to a resolution: the pathologist who injected tissue from a woman’s buttocks into mice; the journalist who locked herself into a small bag when a military expert couldn’t do it. These people wanted to follow the original Greek meaning of autopsy, to see for themselves. Our curiosity grows with every fresh technique we road-test. New technology is letting pathologists see deeper than ever before into a human subject, without the need to roll their sleeves up. The Virtual Autopsy (VA) table is a new medical visualisation tool built in Switzerland that combines CT and MRI scans to transform images of a dead body into a 3D computer model. Pathologists using it in Germany have found fractures and haemorrhages undiscoverable using conventional autopsies. The VA table also includes a high-resolution scanner, which means the skin can be magnified to better reveal things like bruising or malicious injection points. It also causes less distress to the living, who don’t want to contemplate what they see as the desecration of the bodies of their loved ones.
Some traditional forensic scientists have called the VA table unproven and new-fangled. But as a younger, more tech-savvy generation move into pathology labs, they have begun installing them. By January 2013 three out of the thirty-five forensic science institutes at German universities had one. Forensic pathologists are tending still to use them as a complement to physical autopsies. But the proofs keep building up. In the case of a mountain climber who had fallen to his death in the Swiss Alps, his shattered neuro-cranium, fractured lumbar spine and broken lower leg were all detected without a single scratch from a knife.
Another benefit of the Virtual Autopsy table is that the 3D model it produces can easily be examined by several pathologists independently, saved for future reference and produced in court for juries to judge for themselves. Spilsbury might not have liked the idea, but his martyrs surely would have.
FIVE
TOXICOLOGY
‘Within the infant rind of this weak flower
Poison hath residence and medicine power’
Romeo and Juliet, II, iii
Drugs are frighteningly ambiguous. A small amount of digitalis from the foxglove plant smooths abnormal heart rhythms. But too much can provoke nausea and vomiting, and send the heart careering catastrophically towards death. Paracelsus, the founder of modern toxicology, expressed this idea neatly when he wrote in 1538, ‘The dose makes the poison.’
Poison is one of the oldest weapons humans have used against each other. As science advanced, the job of the toxicologist developed to identify lethal substances and search for antidotes. One man in particular systematised the field. Mathieu Orfila studied in Valencia and Barcelona in the early nineteenth century before moving to Paris to study medicine. In order to find out their effects, Orfila spent three years testing poisons on several thousand dogs, who suffered horrendously. (Anaesthetics weren’t available until the 1840s, and besides, they would have contaminated his experiments.) At the age of just twenty-six he published his encyclopaedic General System of Toxicology; or, A Treatise on Poisons (c.1813), which catalogued all the known mineral, vegetable and animal poisons. The 1,300-page work remained the principal reference work on toxicology for forty years.
In a key section of the Treatise, Orfila described his improvements to the existing tests for the substance synonymous with our image of the nineteenth-century poisoner – arsenic. Orfila had realised that severe vomiting can remove all traces of arsenic from a person’s stomach. By testing the organs of his poisoned dogs, he learnt that the bloodstream spreads arsenic throughout the body. He also demonstrated that buried bodies could absorb arsenic from the soil surrounding them, which can make it appear as though they were poisoned in life. After the Treatise toxicologists tested the nearby soil whenever a body was exhumed.
In 1818 Orfila published Directions for the treatment of persons who have taken poison; together with the means of detecting poisons and adulterations in wine; also, of distinguishing real from apparent death, in order to ‘render popular the most important information contained in my Treatise on Poisons’. People were coming to realise that appropriate first aid could limit the harm of an accidental poisoning. Orfila was both genuinely concerned about the ignorance of the general public, and aware that there was money to be made from this new scientific field. He wrote in the introduction to his book, ‘It is of the highest importance that the clergy, the magistracy, the heads of large establishments, the fathers of families, and the inhabitants of the country’ inform themselves about toxicology. Numerous translations of the book into German, Spanish, Italian, Danish, Portuguese and English cemented Orfila’s reputation. If a lawyer needed a toxicologist to testify at a trial, Orfila was the one to get, especially after he became royal physician to Louis XVIII.
In 1840 Orfila became involved in a cause célèbre, the murder trial of the delicate and refined heiress Marie-Fortunée Lafarge. People came from all over Europe to see her fate decided.
Marie had grown up as an aristocrat in Paris, watching on as her school friends married wealthy men. By the age of twenty-three her desire to do the same had reached such a pitch that her uncle employed a professional marriage broker. It was an easy job. After all, Marie had youth, beauty and a dowry of 100,000 francs. The broker contacted a bachelor, Charles Lafarge, the owner of a thirteenth-century monastery in the Limousin region of central France.
The buildings on the Lafarge estate had started to crumble, but Charles had been determined to restore the family fortunes. He set up a forge in which he invented new smelting techniques. He poured his money into the enterprise, but it stuttered and eventually he was forced to shut down the furnaces. By 1839 he was nearing bankruptcy. There seemed only one route to salvation – a woman with money. Charles had contacted the distant Parisian marriage broker, leaving mention of money troubles out of his profile and concentrating instead on a 200,000 franc evaluation of his estate and a glowing letter of reference from his priest.
Marie took an immediate dislike to Charles. She found him boorish and wrote in her diary that ‘his face and figure were most industrial’. But she did like the idea of an extensive estate, sumptuous couches to lounge on, fragrant gardens to walk in. And surely the owner of an ancient monastery would have a hidden poetry in his soul?
Within four days of meeting the pair were married and sharing a carriage down to Limousin. When Charles began to eat a roast chicken with his bare hands, washed down with a whole bottle of Bordeaux, Marie chose to sit in front with the driver. When they arrived at the house she got an even bigger shock. Her in-laws were dressed ‘in the worst provincial taste’, the furniture was ‘shabby and ridiculously old-fashioned’, and the place was full of rats. On that first night, 13 August 1839, Marie locked herself in her room and wrote an impassioned letter to her husband, begging him to release her from the marriage, ‘Or I will take arsenic, for I have it on me … I am willing to give you my life. But receive your embraces, never.’
After she had calmed down, Marie agreed to stay with Charles on one condition. He could not consummate the marriage until he had secured enough money to renovate the estate. It seemed to the other members of the household that the couple were getting along rather better. Marie enjoyed walking around the ruins of the Gothic church and cloisters. She wrote letters to her school friends which depicted a scene of domestic bliss. She didn’t mention having to buy arsenic to keep down the vermin, however.
Marie then suggested to her husband that she would write a will leaving all she owned to him, on the condition that he do the same for her – standard behaviour for a new couple in love. But Charles cunningly made a secret second will leaving everything to his mother.
Four months after the wedding, Charles returned to Paris for a Christmas business trip to raise funds. While he was away Marie sent him tender love letters expressing how much she missed him, and a homemade Christmas cake. When Charles ate a piece, he vomited soon afterwards. He returned to Limousin, having raised some money b
ut still feeling nauseous. Marie received him with concern and suggested the only place for him was bed. There she fed him truffles and venison. But his condition deteriorated and the family doctor was called. He feared cholera, which put the household in a state of panic.
The next morning Charles had acute cramps in his legs and terrible diarrhoea. No matter how much water he drank he couldn’t keep it down. A second doctor was called, and he agreed that Charles had cholera and suggested that he drink eggnog to build up his strength. But Anna, one of the women employed by the family to tend Charles, noticed Marie stir some white powder into the eggnog before giving it to Charles. When she asked Marie about it she said it was ‘orange-blossom sugar’, but Anna was suspicious, and she hid the eggnog away in a cupboard.
On the afternoon of 13 January 1840 Charles Lafarge died. By this point Anna had told other members of the household of her fears. Marie’s calm reaction to the death of her husband, which had at first seemed dignified, began to look suspicious. The next day Marie went to her notary with what she believed was Charles’s last will and testament.
Meanwhile, Charles’s brother went to the police. Two days after Charles’s death, a justice of the peace came to the estate, arrested Marie and launched an investigation. Local doctors tested Charles’s eggnog, his stomach and some of his vomit. They found traces of arsenic in the eggnog and stomach, but nothing in the vomit.
Things looked dark for Marie, but her lawyer had an idea. ‘Knowing that in such affairs M. Orfila is the prince of science’, he wrote to him. Orfila replied explaining that the local doctors had used arsenic tests dating back to the seventeenth century. What was needed was his refined version of a test developed four years ago by the English chemist James Marsh. When Marsh published the details of his extremely sensitive test for arsenic the Pharmaceutical Journal of London enthused: ‘The dead are now become the witnesses whom poisoners have most to fear.’ There were some problems with the Marsh Test, but Orfila had worked through most of these. Backed up by another test invented two years later by Hugo Reinsch, the Marsh Test would remain the standard for arsenic until the 1970s, when more sophisticated methods were developed using gas chromatography and spectroscopy. Armed with Orfila’s letter, the lawyer discredited the original test, and the judge ordered the local doctors to do it again according to the more modern Orfila version.
The doctors performed the test on Charles Lafarge’s stomach, his vomit and the eggnog. This time, they found nothing.
By now the prosecuting lawyer had got hold of a copy of Orfila’s Treatise on Poisons and read it carefully. Severe vomiting, he now knew, could remove all traces of arsenic from somebody’s stomach. Moreover, once the bloodstream passed through the stomach it could take arsenic to the other organs. He told the judge it was necessary to dig up Charles’s body and test his organs. The judge agreed and the local doctors performed another Marsh test, this time in front of a crowd of spectators, some of whom fainted at the ‘fetid exhalations’. Yet again, they found no arsenic. Upon hearing the news in court, Madame Lafarge wept tears of joy.
In a last ditch effort, the prosecutor asked the local doctors how many times they had carried out the Marsh Test in their career. Not once, they admitted. The prosecutor pleaded with the judge that this trial was too important to be decided by a couple of provincial doctors. The only person fit for the job, he argued, was the world’s leading toxicologist, Doctor Mathieu Orfila himself. Arriving on the express train, Orfila set to work immediately, macerating what was left of the organs, ‘liver, a portion of the heart, a certain quantity of the intestinal canal, and a part of the brain’. And this time, the Marsh Test à l’Orfila produced a positive result. For good measure, Orfila demonstrated that the arsenic had not come from the soil by Charles’s coffin.
Marie Lafarge, who was convicted of murdering her husband Charles with eggnog laced with arsenic
Madame Lafarge was sentenced to life imprisonment with hard labour. From jail she published her memoirs in 1841, protesting her innocence, which she continued to do until she died of tuberculosis aged thirty-six.
Orfila’s performance of the Marsh Test would come to be seen as a watershed moment in the fight against murder by poison – a vindication of forensic toxicology. Yet in the immediate aftermath of the trial the public felt dizzy, unable to decide if forensic toxicology was a science, an art or a game. One newspaper summed it up: ‘Within two days the accused was declared innocent by the verdict of science, and now she is judged guilty by the verdict of that same science.’ Getting a forensic toxicologist involved in a suspicious murder appeared to be only half the battle. It had to be the right forensic toxicologist.
Marie Lafarge was one nineteenth-century arsenic murderer among many. Her fellow poisoners were motivated by money, revenge, self-defence, even sadism. The French made their most popular motivation clear when they dubbed arsenic ‘poudre de succession’ (inheritance powder). On the other side of the Channel, in England and Wales, there were ninety-eight criminal poisoning trials between 1840 and 1850. It might seem strange that such a poisonous decade came on the heels of the 1838 Marsh Test. But the truth is that, before the test, coroners were much more likely to pronounce victims of arsenic ‘dead by natural causes’.
The reason was the difficulty of establishing it as a murder method. Arsenic was virtually tasteless – some even said it had a slightly sweetish taste, odourless, and cheaply available from all manner of shops. The body cannot excrete it, so the heavy, metallic element builds up in the victim’s system, mimicking the slow deterioration of a natural disease. Those who digest it suffer a range of symptoms with varying degrees of severity. Hypersalivation, abdominal pain, vomiting, diarrhoea, dehydration and jaundice can all be a result of arsenical poisoning. Because reactions are so variable, killers could strike more than once without arousing the suspicion of local doctors, who diagnosed an apparently random mixture of cholera, dysentery and gastric fever. Intelligent arsenic killers usually went down the chronic rather than the acute path of administration, favouring introducing small amounts over a long period rather than one large dose, as sudden, violent death throes encouraged suspicion.
In response to this, in 1851 Parliament passed the Arsenic Act, making it harder to buy arsenic over the counter. Sellers had to be registered and buyers had to sign and give a reason for their purchase. Unless it was for medical or agricultural use, all arsenic had to be coloured with soot or indigo, so it looked less like sugar or flour.
But the Arsenic Act and the Marsh Test did not deter all would-be killers. In 1832, Mary Ann Cotton (neé Robinson) was born in a village near Durham in the north-east of England. When she was nine, her father died after falling down a mine shaft and the family fell on hard times. Mary Ann was a bright girl and in her teens she taught at the local Methodist Sunday School.
When she was nineteen Mary Ann fell pregnant to a miner called William Mowbray and together they travelled the country looking for work. Mary Ann gave birth to five children during this nomadic period, but four of them died, possibly from natural causes.
In 1856 the couple moved back up north, where Mary Ann had three more children by Mowbray, all of whom died of diarrhoea. Although her grief didn’t prevent her from claiming on the life insurance policies she’d taken out on all three of them. Then Mowbray injured his foot in a pit accident and had to convalesce at home. Soon he became ill and was diagnosed with ‘gastric fever’, and died in January 1865. Mary Ann went down to the office of the Prudential Insurance Company and collected the £30 policy which she had recently encouraged Mowbray to take out.
Over the next dozen years Mary Ann became the most prolific female serial killer in British history. Although it will never be known exactly how many people she poisoned with arsenic, she likely murdered her mother, three of her four husbands (the other one refused to take out a life insurance policy), a lover, eight of her twelve children, and seven stepchildren – at least twenty people in total.
In
1872, Mary Ann set her sights on Richard Quick-Mann, a customs and excise officer who was significantly richer than her previous working-class husbands. Only her 7-year-old stepson, Charles Cotton, stood in the way. She tried fostering him with one of his uncles but failed. Then she took him to the local workhouse. When the superintendent refused him entry unless Mary Ann accompanied him into their care, she told him that the boy was sickly and if the superintendent didn’t change his mind, he would soon die ‘like all the other Cottons’.
All other options having failed, she poisoned Charles. The workhouse superintendent heard about his sudden demise and went to the police. The doctor who had attended Charles before he died carried out an autopsy and found no evidence of poison. So the coroner ruled death by natural causes. But the doctor had kept Charles’s stomach and intestines and, when he subsequently performed a Reinsch Test on them, he discovered the lethal poison.
The bodies of Mary Ann’s most recent victims were exhumed and found to contain high levels of arsenic. Her defence lawyer argued that Charles had inhaled arsenic fumes from green paint on the wallpaper of his room. But, under the weight of the evidence from the exhumed bodies and other witness statements, Mary Ann was found guilty of murder and sentenced to death. It seems extraordinary now that no one suspected her, but until she poisoned Charles she had been too careful, clever and charming, changing her name and moving house too often, to be found out. Moreover she lived in a world in which infant mortality among the working classes may have been as high as 50 per cent.
But once she was hanged, her notoriety was guaranteed. A broadsheet rhyme was coined that began ‘Mary Ann Cotton – she’s dead and she’s rotten’, and the story ran in the newspapers for months. Did she just do it for the money? Or were there even darker forces at play? Could it happen again? Why did it take so long to catch her? Might anyone be able to get away with a poisoning?
