The man...kept his hand upon Socrates, and after a while examined his feet and legs; then pinched his foot hard and asked him if he felt it. Socrates said no. Then he did the same to his legs; and moving gradually up in this way let us see that he was getting cold and numb. Presently he felt him again and said that when it reached the heart, Socrates would be gone.
The coldness was spreading about as far as his waist when Socrates uncovered his face—for he had covered it up—and said (they were his last words): “Crito, we ought to offer a cock to Asclepius. See to it, and don’t forget.”
Plato, The Last Days of Socrates, c. 395 BC
Punishment by purging or worse has long been part of a certain political style. Mussolini’s thugs would force political opponents to consume castor oil to cure their waywardness. Sometimes they would administer as much as a liter of the oil, enough to cause severe purging, but not death. At other times the oil was boosted with petrol, in which case it would probably kill. Of course, poisoning for the good of the state or the community went back much further, to sometime before Socrates was condemned to drink hemlock.
It may have been a wise move to accept that fate in order to win immortality. Socrates was something like 71 years old and had experienced a good life. Thanks to his dramatic death, today we recall him and his fate far better than we recall the death of almost any other Greek philosopher.
The state poison, as it was referred to, used a species of hemlock known as cicuta, perhaps mixed with other poisons—there is still some debate about this. The dose administered often was not fatal, and the condemned person often needed a top-up. An account of the execution of Phokion in 318 BC describes how “having drunk all the Hemlock juice, the quantity was found insufficient and the executioner refused to prepare more unless he was paid 12 drachmas.” Phokion was about two years old when Socrates died, and he lived to more than 80, but he, too, chose to die with dignity.
The name of the poison has been a major source of confusion, because hemlock means several different things to us. The hemlock of the Greeks caused numbness that increased until the heart failed or breathing stopped. The symptoms were like those of suffocation, and in Phaedo, Plato describes a slowly rising paralysis that started at the feet and moved up the legs to his chest, with Socrates’ mind staying clear until the end.
This gentle death described by Plato just did not seem to add up with what modern observers thought they knew about hemlock, but it seems most authors relied on information about the wrong poison. Working on the assumption that he had been given water hemlock, they said, rightly, that Socrates’ death should have been more violent.
If that were the case, how should we explain Aristophanes’ description of death by hemlock in The Frogs, written six years before Socrates’ death? As an account, it matches that of Plato. The confusion probably rests with Nicander, who may have been a Greek-speaking doctor in the Roman army, because he has given us an account of hemlock poisoning very different from the versions we have from Plato and Aristophanes. In his Alexi-pharmaca, Nicander describes hemlock victims as suffering from a terrible choking and convulsions, symptoms also observed by Swiss anatomist Johannes Wepfer in 1679. Wepfer noted the differences between his firsthand report and the account in Phaedo. He took it that water hemlock and poison hemlock worked the same way, and so felt compelled to question Plato’s version.
Conium maculatimi
It was a nineteenth-century Scottish toxicologist, John Hughes Bennett, who got close to the truth, thanks to Duncan Gow and his children. Gow was a poor Edinburgh tailor whose children brought him a parsley sandwich in which the “parsley” was really hemlock. There were no convulsions and no choking but progressive paralysis over the space of about three hours, followed by death—the tailor remained lucid almost to the end. Bennett established the symptoms, performed an autopsy, and had the plant material positively identified. There could be no doubt Gow’s gentle death from Conium maculatum was like the death Plato described in Phaedo. (It should also be pointed out that, tragic though it was, the children’s mistake was a fairly common one. Poison hemlock belongs to the Umbelliferae family, other members of which include carrot, parsnip, celery, dill, and parsley.)
So why was Socrates condemned to death? Basically, because he got up people’s noses, but the story goes back a few years before the execution. In 410 BC, the Athenian oligarchy was replaced by a new democratic regime. In 406 BC, the Athenian navy won a sea battle against the Spartans, but, with a storm brewing, they headed for home without picking up the sailors who had fallen overboard, fearing the whole fleet would be lost in the storm. Some 2,000 men were lost, and the popular assembly was baying for blood. They wanted the leaders subjected to a mass trial and executed for cowardice for leaving the sailors to drown.
Socrates, president of the assembly that day, declared the mass trials illegal and agreed to separate trials. In doing so, he made some dangerous enemies, and by 399 BC, they were after his blood. The vote was 280 to 220 to condemn Socrates on the pretext of “corrupting Athenian youth.” As his accuser, Meletus, had called for capital punishment, it was now up to Socrates to propose an alternative, such as exile. Instead, he said he deserved reward as a public benefactor, and while he offered to pay a token fine of one mina, which he later raised to thirty minas, he made no serious counterproposal, and so was sentenced to death.
Phokion, on the other hand, was a general and statesman who openly supported the aristocratic party of Athens, and his sympathies for the traditions of Sparta gave his opponents the leverage they needed. Accused by his political enemies of complicity with the Spartans, Phokion was also sentenced to death, and like Socrates, obeyed the judicial decision by drinking hemlock.
It is a paradox that even today, people who would normally shy away from murder, especially murder by poison, seem more willing to condone murder when it is done in some abstract way, for the good of the state. Right-to-lifers see no contradiction in enthusiastically supporting any move by the authorities to execute murderers by poison, rope, or chair. Lethal injection is now the most common form of execution in the United States.
The same authorities take a dim view of others poisoning. When Richard Roose allegedly tried to kill Bishop John Fisher and some of his household with arsenic-laden porridge during the reign of Henry VIII, an act made poisoning punishable by being boiled alive. Two others died as Roose had done before the punishment died with Henry.
Poisoning saw a brief upsurge at the end of World War II, with a number of prominent Nazis taking poison tablets rather than face the dishonor of defeat or the War Crimes Tribunal. A few details have now come to light of a vengeful poisoning attempt launched against German prisoners by Holocaust survivors. The German prisoners were members of the Nazi elite guards, awaiting their trial for war crimes. They were being held in Stalag XIII.
In the spring of 1946, a small group of Jews who had escaped from the ghetto in Vilnius, Lithuania, banded together under the name Avenging Israel’s Blood. Having discarded their first plan, poisoning a German town’s water supply, an act as genocidal as any death camp, they targeted people they saw as more deserving of punishment. They used arsenic (probably arsenious trioxide) smuggled in from France to paint 3,000 loaves of bread bound for Stalag XIII with what they hoped would be a lethal amount of arsenic.
Accounts vary, but probably at least 2,000 prisoners became ill. It is less certain how many, if any, died. Very little has been published on the incident, perhaps because it taps straight into the medieval myth of the Jew as poisoner, a common excuse for anti-Semitism.
Certain states seem more at ease with the use of poison than others. There were two earlier attempts on Bulgarian dissident Georgi Markov’s life before he was killed in 1978. The first involved a toxin being slipped in his drink, and he was also attacked in Sardinia, before he had a ricin-filled pellet fired into him at close range by a Bulgarian agent using a modified umbrella.
Markov’s was the second such attack, as Vladimir Kostov had been similarly attacked in Paris the month before. Kostov became ill but did not die, and his pellet was only found after the fatal pellet was removed from Markov and Kostov was re-examined. Two years later, Boris Korczak, a CIA double agent and former Soviet citizen, was also shot with a ricin pellet, and while some reports say he died, he actually survived.
In most cases, it is not enough for a poison to get into the body: it must enter the cell itself, and this means getting past that amazing surface, the cell membrane. Much of the membrane is a sheet of fairly inert stuff called phospholipids, but across the surface there are dotted some special carriers that take certain kinds of molecules as they drift past, and either admit them because they have the right key, or actively gather them in.
Most chemistry involves things spreading out to a randomly even distribution, but the active carriers in the membranes buck this tendency (as long as some poison doesn’t come along and block the carrier!). There are, however, other ways in which a chemical, even a poison, can end up inside a cell.
A molecule or particle may be engulfed, taken into a pocket of the cell membrane that wraps around the particle and then opens up on the inside. This is how insoluble uranium dioxide and asbestos get into the cells of the lungs. Then there is facilitated diffusion, which requires a membrane carrier but also needs a diffusion gradient, passive diffusion through the phospholipids of the membrane, and filtration through pores.
Perhaps the most fearful of poisons in recent years, at least in the view of the media, is ricin, a small and rather nasty molecule from Ricinus communis, the castor oil plant. The plant is common in many parts of the world, the toxic material is fairly easy to separate out from the seed, and it has a particularly diabolical way of disrupting the cell, so just one molecule could kill a cell. In addition, ricin needs no carrier.
Ricin is a smallish protein in two parts, called A and B. The A chain is 267 amino acids long, and globular. The B chain is 262 amino acids long and shaped like a barbell. The chains are linked by disulfide bridges, and the B chain hooks onto the outside of a mammalian cell by binding to the galactose part of a glycoprotein. (Translation: it finds a suitable hitching post on the outside of a cell and locks on.)
The cell membrane then forms a small bubble, a vacuole that moves into the cell, taking the ricin inside. As the vacuole re-forms inside the cell, the A and B chains separate. The B chain makes a channel through the vacuole membrane, letting the A chain enter the cytoplasm, where it gets to the ribosomes and blocks protein synthesis. The A chain on its own is an enzyme able to remove a specific component from ribosomal RNA. In this way it inactivates the ribosome and so stops protein synthesis. Because it acts as a catalyst, the single subunit is not used up, and it can inactivate many ribosomes, about 1,500 a minute. While there can be a few million ribosomes in a cell, the damage soon begins to take effect, as the cell goes out of control.
The disulfide bridge linking the two halves of the ricin molecule is a simple break point that is intended to be fractured when the time is right. An enzyme is able to carry out its function because it is the right size and shape: in fact it only stays in the right shape because there are disulfide bridges holding the protein in a particular arrangement. This is a weak point which can be targeted by heavy metals such as thallium and arsenic.
In 2004, Viktor Yushchenko, who won the presidency of Ukraine in early 2005, was allegedly poisoned by someone while campaigning. His symptoms were dismissed by opponents as the result of eating “bad sushi and cognac,” but his face showed clear signs of chloracne, a symptom of dioxin poisoning. Tests in Vienna in December 2004 pointed to dioxin as the cause. As yet, nobody has been accused of poisoning him, but there are several suspects.
Political assassination by poison is almost as old as history. Generations of the Borgias turned the Vatican and Pontificate into a scandal. According to some, the family used a white powder, La Cantarella, that may have contained arsenic, or maybe phosphorus, or perhaps lead acetate, but most probably all three. It was supposed to have a sugary and pleasing taste and could be added to food or drink. The family kept a staff of Italian astrologer-chemists who worked with mercury, arsenic, phosphorus, hemlock, monkshood, henbane, yew, and poppy. Some of the activities attributed to the Borgias may have been exaggerated. All the same, they gave the writers of their day plenty of material:
Can there be a more express act of justice than this? The Duke of Valentinois having resolved to poison Adrian, Cardinal of Corneto, with whom Pope Alexander VI, his father and himself, were to sup in the Vatican, he sent before a bottle of poisoned wine, and withal, strict order to the butler to keep it very safe. The pope being come before his son, and calling for drink, the butler supposing this wine had not been so strictly recommended to his care, but only upon the account of its excellency, presented it forthwith to the pope, and the duke himself coming in presently after, and being confident they had not meddled with his bottle, took also his cup; so that the father died immediately upon the spot, and the son, after having been long tormented with sickness, was reserved to another and a worse fortune.
Michel de Montaigne, Essays, 1575
The Duke of Valentinois was Cesare Borgia (1476–1507), who became the bishop of Pamplona at 16 and a cardinal at 18, while his father became pope. There are variations between versions, but the two did indeed dine with Corneto. The next day the two Borgias and some other guests were seriously ill. The cause may have been malaria, but according to rumor the wine had been poisoned. Alexander died rather horribly, but Cesare was a fit young man, and though critically ill for weeks, he survived. The other popular rumor at the time was that the dishes had been switched, and the wrong persons fell victim.
Cesare was reputed to have a ring that had twin lion heads with sharp teeth. He would greet victims with a warm handshake, and that was that. His father, Pope Alexander VI, had a cabinet in his Vatican apartments that he would ask victims to unlock for him. The lock was stiff and there was a sharp point in the handle of the key that pricked the palm of the user, who would soon be dead. Lucrezia Borgia, on the other hand, was a famous beauty who took three husbands, but there is no evidence that she followed the family poisoning tradition.
Political assassination does not have to be done by stealth. Cultures around the world have a history of legalizing the removal of unwanted citizens by sentencing them to trial by ordeal. Unfortunates could be tortured to within an inch of their lives, and beyond, or forced to ingest a lethal dose of their inquisitioner’s poison of choice. The guilty would succumb to the poison, the innocent, theoretically, vomit and survive. One poison used in this way is the “ordeal” bean or Calabar bean.
Physostigma venenosum
To botanists, this is Physostigma venenosum, a climbing perennial in the pea family, which can grow to 50 feet in the southeast corner of today’s Nigeria. According to Taylor, the bean was used in the nineteenth century on the western coast of Africa in an ordeal for people suspected of witchcraft or accused of serious crime. The bean, known locally as eséré, was also used in duels, with two adversaries each consuming half a bean. The accused would be given a drink of the pounded beans infused in water, which was said to be fatal within an hour. People were so confident in the accuracy of the test that suspects would voluntarily take an emulsion of the seed to prove their innocence.
Taylor reports Sir Robert Christison, one of the most famous toxicologists of his day, as saying that many an innocent person thus paid the penalty for an undue reliance on superstition—and Christison would know. In his usual adventurous style, in February 1855 he tried one-eighth of a bean, six grains, and reported the results. When he detected no sensation, he doubled the dose to a quarter of a bean, and reported feeling the will but not the power to vomit, a slowing of the heart, and drowsiness. This dose was probably getting perilously close to the safe limit.
It was a simple and direct course of justice and, as such, heartily disapproved of by the British colonizers. Hoping to end the practice, they banned the cultivation of the bean, but, given that the bean flourished in the wild, the ban was not terribly effective.
Some Western colonists who were prepared to learn from the local inhabitants discovered that the beans could be swallowed whole with little ill effect; useful knowledge for anybody captured by hostile tribesmen.
The lack of pain reported by Christison led some to suggest that the Calabar bean might be used to dispatch criminals, but before long other, more therapeutic, properties of its active ingredient, physostigmine, were being noticed. Where atropine (belladonna) dilates the pupils of the eye, physostigmine makes them contract, and ophthalmologists greeted the new substance enthusiastically.
Today, new uses for physostigmine are still being found. As far back as 1898, it was discovered that injections of physostigmine caused ejaculation, allowing impotent men the chance of becoming fathers. Paralyzed men have successfully impregnated their partners thanks to physostigmine injections and artificial insemination. Physostigmine is routinely used to counter the effects of curare and atropine. (Appropriately enough, atropine is used to treat those poisoned by the bean!) Physostigmine binds to the same enzyme as sarin, but only temporarily, whereas sarin binds permanently, so there is every prospect that a suitably timed injection could protect those in a battle zone from the effects of sarin gas.
The Pythagoreans abstained from eating beans. While this information has traditionally given rise to intestinal humor in generations of schoolchildren, it might be worth considering that a number of early scholars were fairly peripatetic. The bean family has a number of deadly members, so perhaps there was more common sense to this rule than meets the eye.
It’s a short step from sanctioning the use of poisons to remove individuals from the political arena to wholesale removal of opponents from the field of battle.
Poison has had a long, if less than honorable, history, and the scientific advances of the last 50 years mean that ever more insidious and deadly poisons are there for the dangerous, unscrupulous, or downright mad to unleash upon their fellows. Such is humanity.