Chapter 3

Poisonous Plants and Frightful Fungi

WHEN OUR MOTHERS TOLD us not to put just anything in our mouths, they had a point. Many plants, even those in the garden, that might tempt a young child’s curiosity and need to touch and taste, contain poisonous substances. Even the most innocent looking of these plants can in fact be a double-edged sword: for example, rhubarb stalks are eaten, but their leaves are discarded, as these leaves contain highly poisonous oxalic acid.

A plant poison may be concentrated in a specific part of the plant, such as the fruit or the root, or it may be distributed throughout the plant tissue. For thousands of years, the effects of these plants have been explored. Like most poisons, in moderation some can have positive effects on various body functions, while large doses can be deadly. For example, alkaloids (nitrogen-containing substances produced by plants) have been used as medicines for thousands of years in drugs such as atropine, morphine and quinine, with positive results. (See Appendix I.) Even today these substances are used, administered in carefully calculated doses. It is wise to remember, though, that there are no safe drugs, only safe ways of using them. We all know what happens from a morphine overdose. And we’re about to find out what happens when these drugs end up in the wrong hands.

Poisonous plants that paralyse

Curare is a crude extract made from a woody vine called Pareira, mixed with extracts containing strychnine, which is derived from various plants of the Strychnos species. Around the world, plant products have been used as arrow poisons, for hunting, execution or warfare, and curare is one such example.For instance, South American natives have used it for centuries to poison the tips of their arrows. Curare blocks the nerve signals to muscles, causing relaxation and paralysis of the voluntary – skeletal – muscles, which can kill. It does not affect the involuntary – smooth – muscle, which produces the slow, long-term contractions of which we are unaware, such as in the gut, the bladder or blood vessels.

Miss Christina Edmunds, a spinster living alone in Brighton, became infatuated with her doctor, Dr Beard, in 1870. The doctor began to receive a stream of romantic letters from her, which he kept hidden from his wife. In September that year, Miss Edmunds obtained a quantity of strychnine on the pretext that she was being plagued by stray cats.

One evening when the doctor was out, she took some poisoned chocolates round to his house and offered them to Mrs Beard. The doctor’s wife selected one but quickly spat it out because it tasted unpleasant. The next day she suffered diarrhoea and felt rather unwell but said nothing to her husband. Miss Edmunds, however, did tell the doctor about it. He felt obliged to tell her she was no longer welcome in his house and warned his wife to be on her guard. Shortly afterwards the doctor went away for three months.

During this time, Miss Edmunds tried to show that the doctor’s wife had been poisoned by accident. She felt that this would be a way of getting back in his good books. Unfortunately her method of achieving this was to buy even more chocolates, which she also laced with strychnine. She then handed them out to children in the town. As a result, a number of children became ill and one child died. Poisoned fruit and cakes were then sent out, and the people who ate them were lucky and survived. Investigations began and eventually the sender of the poisoned chocolates, fruit and cakes was discovered to be the infatuated spinster.

Edmunds was arrested in August 1871. At her trial in the following year, at the Old Bailey, her mother told of a long history of insanity in the family. The jury, however, were unimpressed by this and found her guilty of murder. She was sentenced to death but the doctors who examined her all agreed that she was quite mad. So the Home Secretary commuted her sentence and sent her to Broadmoor, a hospital for the criminally insane, and there she died, some 35years later, in 1907.

Strychnine is an alkaloid produced by the seeds (nuts) of Strychnos nux vomica. The symptoms of strychnine poisoning are mainly those due to overstimulation of the central nervous system. This poison competes with glycine, an inhibitory neurotransmitter, which normally switches off nervous impulses. This competition with strychnine results in a continual stimulatory effect, which can eventually result in death.

The first signs of poisoning are tremors and slight twitching; then stiffness of the face and limbs develops within 15 to 30minutes of ingestion. These preliminary symptoms are followed by the sudden onset of painful convulsions. Initially the movements are intermittent but spinal tetany (twitching and spasms) quickly appears, involving all the muscles in a symmetrical fashion. The body becomes rigid, and the contraction of the facial muscles produces a characteristic grinning expression, known as ‘risus sardonicus’.

Eva Rablen was the attractive second wife of Carroll Rablen. They lived in Tuttletown in California. Mr Rablen was deaf, following an injury during World War I. His new wife loved dancing and despite his deafness, he took her to dances, sitting it out while she danced with other men. In April 1929 the couple attended the regular Friday night dance. Carroll waited out in the car while Eva danced the night away.

At about midnight, she took him a cup of coffee and some refreshments, handed them to him in the car and then returned to the dance. Within seconds of drinking some of the coffee, Carroll was writhing on the floor of the car in agony. People heard his cries and came running. He managed to tell them how bitter the coffee had tasted, but was dead before the doctor arrived. His wife seemed heartbroken; the police considered suicide and on analysis of the stomach contents by a local chemist apparently found no trace of poison.

However, Rablen’s father told the police that he suspected his daughter-in-law Eva because of a number of insurance policies she had taken out on Rablen’s life. A police search of the area around the schoolhouse, where the dance was held, found a bottle bearing the label ‘strychnine’. This bottle had come from a pharmacy in a nearby town. The pharmacist traced the sale of the strychnine in his poison register to a Mrs Joe Williams. This lady had said, at the time of purchase, that she wished to use it to kill gophers.

In due course, Eva was identified as Mrs Joe Williams, and she was arrested. An eminent chemist and criminologist, Dr Edward Heinrich, was called in and found traces of strychnine in the stomach of the dead man and on the coffee cup he had drunk from. Strychnine was even identified from a coffee stain on the dress of another woman who was at the dance. Eva had spilt coffee on this woman’s dress as she carried it out to her husband. At her trial Eva decided to change her plea to guilty and was sentenced to life imprisonment.

All forms of sensation are heightened by the action of strychnine, and since consciousness is not impaired, the victim may become extremely distressed. Even the most minor of sensory stimuli can trigger painful spasms and convulsions. The body arches backwards due to contraction of the muscles of the diaphragm, together with a spasm of the chest and abdominal muscles. This spasm can even result in respiratory arrest. The convulsions usually last for a minute or two and are then followed by a period of depression, with a second convulsive seizure usually following within the next ten to 15 minutes.

Death results from medullary paralysis in the brain, usually following the second seizure, although in some cases it has not occurred until during the fifth seizure. The fatal dose, by mouth, is usually about 100mg but can be as little as 16mg. As strychnine is excreted very slowly by the body its action can be cumulative.

Jean Pierre Vaquier was a Frenchman and a poisoner. He was a wireless operator and met Mrs Mabel Jones when she was staying in Biarritz, alone, on holiday. The Frenchman didn’t speak a word of English, and Mabel didn’t speak French, but they became lovers – her first affair in some 19 years of marriage. Alfred Jones, her husband, was the landlord of the Blue Anchor Inn at Byfleet, Surrey.

After a few weeks, Jones sent his wife a telegram asking her to return home, which she did a few days later. Shortly after her return, she received a telegram from her lover, telling her that he was now in London. She went to his hotel and they resumed the romance for a day and a night while her husband was away on business.

She then returned home to the Blue Anchor and, shortly afterwards, Jean Vaquier appeared, requesting a room. Jones, who knew nothing of the romance, got on very well with him, so much so that he even lent him some money.

Two weeks after his arrival in London, the Frenchman went to a chemist’s shop near Holborn and produced a list of chemicals, which he said he required for experiments concerning the wireless. The list included chloroform, mercury perchloride and strychnine. The chemist was somewhat reluctant to supply what amounted to enough poison to kill at least 12 people. However, the sale was made and the customer duly signed the poison register.

Every night, the landlord Alfred Jones got drunk. The French lover had become rather useful during his stay, carrying the inebriated Alfred up to his bed each night. To treat the resulting hangover, Jones normally started each day by taking a teaspoonful of salts mixed in water. One morning, Jones came down to breakfast and as usual prepared his hangover cure. He drank the solution, but this time exclaimed at its bitterness. His wife dipped her finger in the salts and tasted them; they were very bitter indeed and looked different too.

She gave her husband table salt and water to make him sick but his body went into spasm and he died in agony later that day. The next day Mrs Jones accused her lover of killing her husband. Vaquier admitted that he had done it – for her. A post-mortem proved that poor Alfred had died of strychnine poisoning. Although Vaquier had carefully washed out the salts bottle, he did not notice that some crystals had fallen from the bottle onto the table; on analysis they were found to be strychnine.

Later when Vaquier’s picture appeared in the newspaper, it was recognised by the chemist who had sold him the strychnine, even though he had used a false name when he signed the poison register. Vaquier appeared in court in July 1924, claiming that he bought the poison at the request of Mrs Jones’ solicitor, but he was found guilty of the murder of Jones and hanged at Wandsworth the following month.

In bygone days strychnine was included as an ingredient in a number of ‘tonics’, albeit in a very small quantity. Today, synthetic versions of curare are a major component of modern anaesthesia, paralysing the patient and allowing the anaesthetist to use less of other drugs, like muscle relaxants, while keeping the patient unconscious but still very much alive.

Thomas Griffiths Wainewright, English art critic, painter, forger and alleged poisoner, was born in Chiswick, London, in 1801. At 18, he joined the army but quickly tired of that and so became a painter and writer. He managed to earn a little by writing art criticisms under a number of pseudonyms. In 1821, he married Eliza Frances Ward and then committed forgery on a document, with which he defrauded the Bank of England of more than £2,000, a great sum of money in those days.

In 1829, his grandfather died of a fit and Wainewright inherited all his wealth. As he was in severe financial difficulties at the time, this inheritance was immediately seized upon by his creditors to pay off his debts. Years later, it was thought that Wainewright probably poisoned his grandfather with strychnine.

His mother-in-law came to live with Thomas and his wife Eliza, bringing two other daughters along too. Within a year, the mother-in-law was dead, no doubt poisoned by Wainewright. He almost certainly poisoned his sister-in-law with strychnine in 1830, as she had been fraudulently insured for £16,000. Two actions were brought by Wainewright to enforce the payment of this money but both failed because the insurance company had become suspicious about the claim. Wainewright probably poisoned his uncle and several other people too.

He then fled to France, where he poisoned the father of a girl he had met, but not before insuring the man’s life for £3,000. In 1837, he returned to England but was soon recognised and arrested. He was put on trial and sentenced to transportation for life as punishment for the forgery of the bank draft in 1821. Transported to Van Diemen’s Land, which today is called Tasmania, he painted portraits and ate opium for some years, before dying in Hobart Hospital in 1847. On his deathbed, he finally admitted to poisoning his mother-in-law but left the rest of the deaths unaccounted for.

Poisonous plants that affect the heart

Digoxin is a type of sugar derivative, called a cardiac glycoside, made from the effects of sunlight within the leaves of the Foxglove plant. These leaves have been used to treat heart failure (long ago called dropsy) for hundreds of years since they work as a cardiac stimulant: digoxin acts on the heart to increase the force of contraction of the heart muscle.

Drugs called beta-blockers, widely used in medicine for the last 50 years, have the opposite effect. However, digoxin is still used to treat heart failure today, but because the margin between the therapeutic dose and the toxic dose is small, toxic side effects are common.

Early symptoms of digoxin toxicity are nausea, vomiting and anorexia, accompanied by diarrhoea and abdominal pain. The heartbeat also becomes slow and erratic. Then headache, fatigue, weakness, disorientation and confusion occur. There can also be visual disturbance, in which everything appears to have a yellow-green halo around it. However, careful monitoring of the blood level can prevent this.

A number of other plants are used for similar purposes. The Hellebore produces cardiac glycosides in its rhizome. In Russia, Lily of the Valley is used as a source for a similar cardiac stimulant. Ouabain, with an action like that of foxglove leaves, has been used as an arrow poison. This is the poisonous principle from various species of Oleander, which grows in Africa. One species even became known as the ‘Hottentot’s Poison Bush’. Mass executions in parts of Asia used to involve the Upas Tree, as the sap of this tree also contains some of these highly poisonous heart poisons. In the eighteenth century the natives used this sap to poison the wells that provided drinking water for some unwelcome Dutch colonists.

Poisonous alkaloids: black sheep of the family

Remember that alkaloids are nitrogen-containing substances produced by plants. They are many and varied, and they have potent effects on the body.

Belladonna, another name for Deadly Nightshade, contains the alkaloids hyoscine and hyoscyamine, as well as atropine. Deadly Nightshade, as well as henbane (discussed below), is a member of the Solanaceae family of plants, which also includes the potato and tomato, which of course we eat.

Belladonna poisoning is essentially due to the atropine it contains. The symptoms of poisoning are excessive dryness of the mouth, burning and constriction of the throat, dilatation of the pupils, nausea and sometimes vomiting. There is excitement of the central nervous system, with hallucinations, leading to delirium, giddiness and a staggering gait, passing into drowsiness and stupor. The pulse becomes rapid, the face flushed and the breathing jerky and laboured.

In fatal cases, death is preceded by a rapid intermittent pulse, with coldness of the extremities and coma. The symptoms set in rapidly and may last from ten to 15 hours or even several days in fatal cases. The usual fatal dose is only about 100mg of atropine in adults and about one-tenth of that for children. A single nightshade berry can be fatal, but recovery has occurred with prompt treatment after taking as much as 1g. Indeed, one woman in the 1940s survived after taking 50 times the maximum therapeutic dose.

The temporary muscular paralysis that atropine can cause is dose-related and reversible, and treatment for atropine poisoning is fast and effective with an antidote. Atropine is still used today in various medicines, although newer, safer, synthetic analogues have now superseded them for some uses.

One other juicy titbit: the juice of deadly nightshade berries (belladonna), when put into the eyes, causes dilatation of the pupils. This was all the rage in Renaissance times because it supposedly made the ladies look more alluring. We will return to belladonna eye drops in Chapter 12, Murderous Make-Up.

Physostigmine, contained in the Calabar Bean, is the antidote to atropine, and has itself been used as a poison, for which, of course, atropine is its cure.

Its own poisonous use was the reason for the Calabar Bean’s alternative name, the Ordeal Bean. Found near the Calabar Coast in West Africa, these beans were used in trials by ordeal, in executions and even for the divination of witches. Eight beans were ground and added to water as a drink. If lucky, the recipient vomited and survived.

Other related species such as Woody Nightshade, Henbane, Mandrake and Datura are similarly poisonous plants. All of them contain a number of toxic alkaloids, including hyoscine. Hyoscine is still used today in travel sickness tablets and transdermal patches, as well as in other uses such as an antispasmodic in the treatment of irritable bowel syndrome, and sometimes even as premedication prior to surgery.

Dr Hawley Harvey Crippen was a patent medicine salesman and a doctor of sorts. Born in Michigan, USA, Dr Crippen was a mild-mannered man who did not get on very well with women. He found his first wife to be a worrier, and he got on just as badly with his second wife, Cora Turner, a music hall artist whose stage name was Belle Elmore. Dr Crippen and Cora moved to London in 1910, but his American qualification in medicine did not allow him to practise in England, so he came to be employed selling patent medicines.

Cora was a strong-willed woman who took in paying guests at their home, 39 Hilldrop Crescent. She made her husband do the housework and generally kept him under her thumb. After a time, Crippen became infatuated with his secretary, Ethel le Neve. He later said that with her he was happy, for the first time in his life. In 1910, he poisoned Cora with hyoscine, giving her deadly symptoms similar to heart failure from this drug overdose, and he then cut up her body and buried it in the cellar.

Crippen explained Cora’s absence to friends by telling them that his wife was on holiday in America. However, the police began an investigation after neighbours saw Ethel wearing some of Mrs Crippen’s jewellery and became suspicious. The doctor and Ethel fled to Canada on board the SS Montrose. He pretended to be a Mr Robinson and Ethel disguised herself as his son. The captain became suspicious of the pair and telegraphed Scotland Yard, its first use for police purposes, and they were both arrested. Dr Crippen was tried for murder, found guilty and hanged at Pentonville Prison in November 1910. Investigations showed that he had purchased five grains of hyoscine (this is about 300mg and would be enough to make 1,000 travel sickness tablets). Ethel was also tried but was acquitted. She later remarried and died in 1967.

Henbane is an Anglo-Saxon plant name that means ‘killer of hens’, which should indicate, to any passing Anglo-Saxon, that this plant is definitely not edible. However, in a magazine article about foraging for wild herbs in the summer of 2008, the celebrity chef Antony Worrall Thompson mistakenly recommended henbane to eat in salads instead of the wild herb, fat hen. The main poison found in henbane is hyoscine.

Mandrake is yet another member of the Solanaceae family that produces hyoscine. This plant was associated with magical or curative properties in the Middle Ages. According to the ‘doctrine of signatures’, this plant, with its Y-shaped root said to resemble the human form, was associated with enhanced fertility and reproduction.

Thornapple, another plant of this family, is also rich in hyoscine and other alkaloids. In toxic doses, it can render the victim unconscious and result in an almost painless death. Thornapple also came to be called Jimson Weed because in the seventeenth century some of the early settlers near Jamestown, Virginia, mistook it for spinach and were poisoned after they ate some of it, only narrowly avoiding death.

Aconite, commonly called Monkshood or Wolfsbane, is a beautiful plant when in flower, but deadly. The active component, an alkaloid called aconitine, is present in all parts of the plant, although only the root is used medicinally. Aconite can cause almost instantaneous death with a large dose. A smaller dose will initially cause tingling of the tongue, mouth, stomach and skin. This tingling was an important diagnostic feature in the past, when aconite was still in regular use as a medicine.

The tingling would be followed by numbness and anaesthesia. Other symptoms of aconite poisoning are nausea, vomiting and diarrhoea. There follows excessive salivation, with an irregular, weak and slow pulse, which may later become rapid, and difficulty in breathing, with a cold and clammy but livid-looking skin. The victim develops muscular weakness, incoordination and vertigo.

Death occurs as a result of paralysis of either the heart or respiratory system. The symptoms appear almost immediately and are rarely delayed beyond an hour. In a fatal poisoning, death usually occurs within two to six hours. A dose of as little as 20-40ml of the tincture has proved fatal in the past.

Hemlock is an umbelliferous plant, belonging to the same family of plants as parsley, parsnip and carrots. The leaves and unripe fruits of hemlock contain very poisonous alkaloids, including coniceine and coniine.

In Ancient Greece, poisoning was a common method of execution. The philosopher Socrates (469-399 BC) was accused of impiety and of corrupting youth by his enemies. At the ripe old age of 70, he was summarily tried and convicted. He refused the option of merely paying a fine, and declined a later opportunity to escape from prison. He was sentenced to die by the traditional Greek method of execution – by drinking hemlock. His death was due to asphyxia, because the alkaloid coniine contained in hemlock causes respiratory arrest.

Theramenes (441-403 BC) was an Athenian statesman and general who committed suicide, also using the traditional drink of hemlock. He may have been forced to drink it, having incurred the displeasure of the most notorious member of the government of Thirty Tyrants, Critias.

Poisonous poppies and other flowers

Opium Poppies are the source of a number of well-known drugs. Raw opium is the dried latex collected from the unripe capsules of the opium poppy. This latex, or sap, contains a mixture of morphine, codeine and a number of other alkaloids. Laudanum, the popular cure-all in the nineteenth century, was simply opium tincture by another name.

Like all drugs, an overdose can be poisonous. Initial symptoms of poisoning with opioids include some confusion and nausea, and possibly skin rashes and urticaria (hives). Excitation and euphoria then follow, then depression, and then possibly restlessness, vomiting and delirium. A characteristic feature of this type of poisoning is the gradual development of coma. As the respiration rate slows, cyanosis develops, and later the blood pressure falls as a result of circulatory failure and deepening coma.

A morphine overdose causes symmetrical pinpoint pupils, which do not react to light, although as death approaches they dilate again. Death is usually due to respiratory failure. The toxic dose of morphine varies considerably with the individual and addicts can tolerate much larger doses than the average person. The fatal dose is usually between 150mg and 300mg.

The toxic dose of opium is about ten times larger than that of morphine, and since its absorption is much slower, the symptoms do not appear so rapidly. Opiate Squill Linctus, perhaps better known as Gee’s Linctus, a cough mixture containing opium and squill, has been subject to abuse, because of its morphine content. There have even been reports of cardiotoxicity – a digoxin-like slowing of the heartbeat – caused by the action of the squill content on the abuser. Squill has been included in the preparation for its emetic qualities, specifically to prevent an opiate overdose, but clearly causes its own problems too.

Other plants, or their fruits or berries, are also poisonous, including the seeds of Lupins and the Laburnum tree, which are both highly poisonous, particularly to children. Many spring bulbs and corms, such as Daffodils, Tulips and Crocuses are also poisonous if eaten, although it is interesting to note that daffodils contain a substance called galantamine, which is now used in the treatment of Alzheimer’s disease.

Poisonous cyanide: deadly in any form

Cyanide is another poisonous plant product, found in the oil expressed from the nuts of Almonds, Cherries, Apricots and Peaches, and even from immature bamboo shoots and young fern leaves. The liquid form of cyanide, formerly called prussic acid, is an intensely poisonous, volatile acid that can cause death within a minute if drunk. The fumes given off from prussic acid are hydrogen cyanide gas, which are just as dangerous.

Cassava is the staple diet for many who live in the tropics. The root, which contains cyanide, is used to make tapioca. It is vital that the cassava is properly prepared to ensure it is safe to eat. Cassava must be cooked in a pot without any lid to allow hydrogen cyanide gas to escape. Some 250mg of hydrogen cyanide can be released from every 100g of fresh root, and this is more than a lethal dose. A lid on the pot would cause the cyanide to remain in the food, and this would poison the whole family when they ate it.

Cyanide interferes with the oxygen uptake of cells, and without oxygen, of course, we die. Poisoning can occur in several ways: by inhalation of the vapour, by ingestion or even by absorption through the skin. It can result from exposure to pesticides, accidental industrial exposure, inhalation of fumes from burning plastics in domestic house fires, or even from eating plants or fruits containing cyanide. Although cyanides have the characteristic smell of bitter almonds, this smell may not always be obvious and indeed some people cannot detect it.

Unconsciousness occurs within a few seconds of taking large doses of prussic acid or other cyanides, and death occurs within five minutes. With much smaller doses, the symptoms of poisoning, which begin within a few minutes, are giddiness, staggering, headache, dilated pupils, palpitations, and difficulty in breathing, then unconsciousness and convulsions, leading to death within 15 minutes to an hour later. If the patient survives for the first hour, they will usually recover. The fatal dose of prussic acid is said to be about 50mg and that of its salts, the cyanides, is about 250mg.

Richard Brinkley lived in Fulham and tried to kill his friend, Reginald Parker, using prussic acid. Reginald, who was an accountant’s clerk, knew that Richard had falsified a signature on a will, and also knew that Richard was desperately worried that he might tell someone about it. The will that he had falsified belonged to an elderly woman who had died in mysterious circumstances, within a few days of signing over all her worldly goods to Mr Brinkley. Richard Brinkley decided to deal with his concern by offering the clerk a bottle of stout that he had poisoned with prussic acid.

Unfortunately, it was drunk instead by Parker’s landlord and landlady, Richard and Daisy Beck, and their daughter, who was also called Daisy. Prussic acid, taken on an empty stomach, can kill very quickly indeed. Within minutes, the mother, father and daughter were all writhing about on the floor. Another daughter hastily summoned the doctor but her parents were dead by the time he arrived. Her sister, Daisy, however, was lucky and survived the poisoning. Brinkley was arrested and claimed in his defence that he had only intended to kill Parker, which he had singularly failed to do.

Further investigation showed that Brinkley had something of a reputation with poisons. A few years previously his wife had been found dead at home. At the time, the police had found a medicine case containing a number of poisons in Brinkley’s study. The case contained strychnine, arsenic, prussic acid, chloroform and ergot of rye. Mrs Brinkley was found to have died of arsenic poisoning, but with no proof to link her death to her husband, the coroner’s jury gave a verdict of suicide.

Shortly afterwards, now widowed, Brinkley became friendly with a young lady named Laura Glenn, who also subsequently died of arsenic poisoning, in Brinkley’s rented room in Chelsea. She left a suicide note, but she was in fact one of a number of women who had once been friendly with Richard Brinkley and had then died of poisoning – not suicide. For the murder of Mr and Mrs Becks, Brinkley was sentenced to hang in Wandsworth Prison in 1907. Right to the end, he refused to admit he had killed anyone at all.

Plants poisonous on contact: look but don’t touch

Some plants can cause problems just by touching them. Poison Oak and Poison Ivy both cause burning and blistering of the skin on contact. The Giant Hogweed, which is classified as an official weed in the United Kingdom, also contains poisons that cause blistering and burning after the skin touches it and then is exposed to sunlight. In the herb garden, Rue can also cause a severe skin irritation in bright sunlight, as can spurges (Euphorbias), which irritate both the eyes and skin and are intensely poisonous if eaten.

Even Leylandii hedging can be a skin irritant, and all parts of the Yew are poisonous, including its berries. Yew hedge clippings from stately homes throughout the UK are collected and processed by the pharmaceutical industry to produce a drug used in the treatment of breast and ovarian cancer called paclitaxel.

Stinging nettles have hollow hairs on their leaves, which are made of silica. Contact with the leaves causes the delicate hairs to break, and histamine leaks out onto and into the skin, causing the typical nettle rash, which is very itchy. However, help is close at hand, as the application of a crushed dock leaf to the affected area is frequently far more effective than using an antihistamine cream.

Toxic beans

The Castor Bean, from which we get castor oil, can also be a danger, as it contains the potent neurotoxin ricin. The beans must be cooked properly for the heat to destroy the ricin. This highly toxic agent initially causes flu-like symptoms, with abdominal cramps and diarrhoea, which develop rapidly and are followed in short order by respiratory and circulatory collapse. There is no antidote and death normally ensues within three or four days. It is so virulent that half a milligram, enough to just cover a pinhead, can be fatal.

One of the most famous victims of poison in modern times was Georgi Markov. One September afternoon in 1978, Markov, a Bulgarian dissident who worked for the BBC World Service in London, was waiting for a bus on Waterloo Bridge when he suddenly felt a sharp stabbing pain in the back of his right thigh. He turned to see a man carrying a furled umbrella, which he assumed had caused the pain. The man mumbled an apology in a thick accent and hurried off to catch a cab. When he got home, Markov looked for and found a small puncture wound on the back of his thigh.

By the next morning he felt very unwell, had a high temperature and was vomiting. He was taken to hospital, and the wound, which was now rather inflamed, was X-rayed. Nothing showed up on the scan but by now his blood pressure and temperature were both dropping. Additionally, his white blood cell count had jumped to three times the normal level, which is an indication of an infection. His doctors suspected blood poisoning and began treating him with antibiotics, but he then became delirious and began having violent convulsions.

He was dead just four days after the wound was inflicted. A post-mortem was held and a lump of tissue containing the puncture wound was removed and sent to the Porton Down chemical warfare research laboratories for examination. The experts at Porton Down found, buried beneath the skin, a small spherical pellet about the size of a pinhead. The pellet had two tiny cavities drilled into it, but there was no trace of any poison that might have caused Markov’s illness.

The pellet was then sent to the Metropolitan Police forensic laboratory, where it was examined using a scanning electron microscope. This showed that the pellet was made of an alloy of platinum and iridium, which was very hard and immune to corrosion. Investigators found that it was also almost invisible when X-rayed. However, the holes in the pellet were considered large enough to have held minute traces of poison, but none now remained.

Investigators quickly deduced that the pellet had been fired by some form of gas-powered device hidden in the furled umbrella, but identifying the poison itself was much more difficult and became a process of elimination. The small amount used and its effects on Markov led the experts to consider the most likely poison to be ricin, a neurotoxin found in the castor bean, about 500 times more poisonous than cyanide. They tested their theory by injecting a pig with a quantity of ricin similar to what could have been contained in the holes in the pellet. The poor animal died within 24 hours and a post-mortem found similar organ damage to that of Markov.

At the time of the attack, Eastern Europe was governed by communist regimes and although the Bulgarians strenuously denied any responsibility for the murder, in fact another Bulgarian émigré had been similarly attacked in Paris the previous year but had fortunately recovered. When a surgeon examined him, an identical pellet was found. This man had been lucky, as the pellet was fired into his back, well away from major blood vessels. It was not until 1991, following a change of regime in Bulgaria, that the new government finally admitted that assassination attempts were made upon a number of dissident former citizens who had moved to live in the West, including Georgi Markov.

Another bean, the Tonka Bean, is used for benefit rather than harm. The Tonka Bean produces a substance called coumarin, or tonka bean camphor, which is used as a flavouring in some foodstuffs. Coumarin derivatives are used as anticoagulants in medicine. This type of anticoagulant is used long term by patients who have had heart or bypass surgery, to prevent any future formation of blood clots, or thromboses. Taken daily as tablets, this type of anticoagulant is said to act indirectly, as it only stops clots from forming – it cannot dissolve any clots that have already formed. To dissolve existing blood clots, which can cause thrombosis or a stroke, a direct-acting anticoagulant such as heparin must be used. Heparin must be injected, because, as it is a protein, if it were swallowed it would be digested like any other protein we eat.

Frightful fungi

Mushrooms and toadstools are the fruiting bodies of fungi that grow in the soil or on wood – particularly wood that is dead and rotting. While some fungi are edible, many are inedible or poisonous. There is no biological difference between mushrooms and toadstools – they are all umbrella-shaped fungi – but generally speaking the edible ones are called mushrooms and the inedible or poisonous fungi of this type are referred to as toadstools. Morels are cup-shaped edible fungi, and the similar-looking but poisonous fungi are called false morels. Many people have been accidentally poisoned because they mistook one for the other. As a rule of thumb: if you are in any doubt, don’t eat it.

Some mushrooms, although edible, are best not eaten by beer or wine drinkers as they contain coprine, an unusual amino acid which inhibits one of the enzymes involved in the metabolism of alcohol. Anyone eating these mushrooms and drinking alcohol to wash them down would get a terrible headache and feel very nauseous, a sort of instant hangover. Some edible fungi also contain hallucinogenic substances. The so-called ‘magic mushrooms’ contain psilocybin and psilocin, which have effects similar to those of LSD.

In August 2008, the novelist Nicholas Evans, author of The Horse Whisperer, and his family fell seriously ill after eating some poisonous mushrooms while on holiday in Scotland. They unfortunately ate a fungus known as the Deadly Webcap, probably in mistake for the similar-looking, but edible and delicious, chanterelle. It was two days later before they became ill.

The toxins in this mushroom attack the kidneys in particular, and the family all ended up in hospital, receiving dialysis and other forms of treatment to support their kidney functions. One month later, neither Evans nor his brother-in-law had any kidney function at all while his wife and sister had only a little. The doctors do not know yet when, if ever, they will get it back.

While some toadstools signal their poisonous nature visually, such as the Fly Agaric – the red toadstool with white spots often depicted in children’s fairy tales – others are the visual equivalent of a silent killer. The Death Cap is far less noticeable than the fly agaric, being a pale olive colour, yet it is this species that is considered to be the cause of 90 per cent of all the fatalities of fungi poisoning, due to the amatoxins and phallotoxins that this species contains.

A single death cap (or amanita) mushroom, which weighs only about 20g, can be fatal. After eating this particular mushroom, the symptoms of poisoning are somewhat delayed, not occurring until from four to 24 hours after ingestion. Then the initial symptoms include abdominal pain, nausea, vomiting and diarrhoea. This last symptom can sometimes be so severe that in the past it was confused with cholera. Dehydration and vascular collapse may follow.

This initial phase of amanita poisoning can then be followed by a period of apparent improvement, when recovery may be foreseen, but two or three days later the more serious phase begins, due to the damaging effects that the amatoxins have had on the liver. Jaundice develops, and there may also be lapses in heart, kidney and central nervous system functions.

Symptoms also include urinary problems, circulatory collapse, convulsions and coma. There is no specific antidote or treatment available. The mortality rate can be as high as 90 per cent if left untreated, but this can be greatly reduced to 15 to 30 per cent with symptomatic and supportive treatment in an intensive care unit.

Another poison victim, Claudius the Roman emperor (10 BC-AD 54), was married several times. His fourth wife, Agrippina the Younger, persuaded him to adopt her son by an earlier marriage, Nero, as his successor, even though Claudius already had a son of his own. Agrippina is believed to have poisoned Claudius with a dish of mushrooms in order to secure the succession of Nero to the imperial throne.

Ergot is a fungus that can infect rye, and sometimes other cereals too. This fungus produces ergot alkaloids, which contaminate the rye flour and so too any bread baked from it. Ergotism was suggested as a possible cause for the so-called ‘bewitchings’ that occurred in Salem, Massachusetts, in December 1691 and even for outbreaks of plague in medieval times. More recently, the medical journal The Lancet carried a report of an outbreak of ergotism in 1979 that occurred in Ethiopia and was attributed to eating infected wild oats.

Two forms of epidemic toxicity of ergotism have been described in the past: the gangrenous and the convulsive. It is rare to find both types occurring together. In the more common gangrenous form, the early symptoms of chronic ergotism include a headache, vomiting, depression, muscular twitching and a staggering gait. Later symptoms are gangrene of the limbs and agonising burning pains, thus the old name ‘St. Anthony’s Fire’ to describe the poisoning. These symptoms occur because the ergot alkaloids are vasoconstrictive and reduce or even totally cut off the blood supply.

In the much rarer convulsive type, symptoms include writhing and shaking with muscle spasms and sometimes extend to hallucinations and delusions, caused by other ergot alkaloids.

A number of ergot alkaloids have been used medicinally in the past. For example, ergotamine was used in the treatment of migraines and ergometrine during childbirth, both given in carefully controlled doses. These drugs have now been superseded by newer, far less toxic, but more effective, agents.

Other fungal toxins can be equally nasty. Aflatoxins, produced by the Aspergillus fungus Aspergillus flavus, can cause gross liver damage and even cancer. A high incidence of cancer was found to be linked to prolonged use of groundnut (peanut) meal and maize, both of which have become contaminated with this fungus and its aflatoxins. Unfortunately both of these crops are the staple diet of many people in Africa, where poor harvests cause widespread malnutrition and infant mortality in rural areas. It is likely that many other mycotoxins (a toxin produced by a fungus) infecting foodstuffs also contribute to human disease, as a result of low-level, long-term exposure. Research in this area continues.

A different species, Aspergillus fumigatus, causes devastating infections of the respiratory system. Infection by Aspergillus can cause a severe acute pneumonia, which can then spread to invade the heart, kidneys, bone, brain, liver and skin, with devastating consequences. Aspergillosis is usually associated with impaired immunity and is due to aflatoxins and other mycotoxins.

If you’ve found fungi fascinating, you’ll be happy to know that fungal toxins will appear again later in this book, in Chapters 9 and 10.