by John Hicks
The meeting to which Viv and I were hurrying was about adoption. After several years of trying to conceive, and undergoing the usual undignified and painful gamut of tests, we had at last come to the decision that if we ever wanted children, we would have to adopt them. At the meeting we began to appreciate the difficulties that lay ahead. Quite rightly, the government adoption agency assesses the needs of the children first. If they can be placed in the tried and tested environment of an already happy family, they are. Infertile couples who have no children are carefully assessed for suitability and put on a list. We settled in for a long and uncertain wait and, to break the tension, took off on a tramping holiday in the Southern Alps.
We were lucky. After only a few weeks we strongly suspected that Viv was pregnant, but how many times had our false hopes been dashed? However, this time the tests seemed to support our hunch. It is beyond me to describe the joy of the first ultrasound scan where we could see that Viv was, indeed, pregnant. It brought tears to our eyes. More amazingly, this miraculous new technology could accurately age our little spark of life. We deduced that our child was conceived on an Alpine herbfield surrounded by snowy peaks. The love of such places certainly seems to have infused her blood; Emily has always loved the great outdoors.
All true scientists will abjure this thesis. The setting in which a conception occurs cannot, of course, influence the personality of the resulting child, any more than a pregnant woman seeing a hare may cause her child to be born with a hare lip. The first is a notion of poesy, the second, of superstition. The science of human fertility is as wrapped in psychology as it is in physiology. What was the rationale behind the years of infertility Viv and I had suffered? Such episodes – whereby an infertile couple conceive just when they’ve given up trying – are not uncommon. It serves to illustrate how much our minds influence our bodies.
Luckily, for Viv and me our barrier to fertility was broken with Emily’s birth. We did not have to wait long for our second daughter, Morwenna, to complete our precious family.
Chapter Eleven
Naughtie Herbs
Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy. – Paracelsus
New Zealand was a benign land for settlers: no snakes and only one rare and slightly venomous spider – the katipo. The giant Harpagornis eagle had been the only large predator. Its talons may have been as large as a tiger’s paw, but it faded to extinction once its food source – the meaty, flightless moa – was hunted to oblivion by early Maori. With a few exceptions even the plants are benign. The early European settlers deplored the sharp-leaved spear grasses (“Spaniards”) that stabbed them and their horses as they rode across the tussock plains. These plants are still bothersome and can leave festering wounds on dogs working sheep in rough country. The xenophobia of the early colonists is revealed in the names they gave these less desirable plants, such as “Horrid Spaniard” (Aciphylla horrida) and “Giant Spaniard” which forms huge clumps up to three metres tall. On dry banks and slopes the back-country is also stoutly defended by the spiny “Wild Irishman” in dense, perverse thickets – now more commonly known by its onomatopoeic Maori name – “Matagouri”. More formidable still is the “Fierce Nettle” (Urtica ferox) – a woody shrub far more dangerous than any nettles the early settlers would have encountered in their home countries. Fatal poisoning in man has been recorded and, as a piece of veterinary esoterica, it is on record that the extract from just five stings can kill a guinea pig. However, by and large, the flora of New Zealand held few dreads. There are very few poisonous plants.
For a vet, this is a bit disappointing. Plant poisonings of livestock make an interesting diversion from the routine of pregnancy testing cattle, palpating rams testicles or trimming cows’ feet.
There is, however, one conspicuously poisonous family of plants, the Coriariaceae. Even for the most ardent classicist, this is a bit of a mouthful. Not surprisingly, the Maori name “Tutu” is preferred. The pioneering farmers were probably not much “into” classical ballet, so this would not have caused them confusion but, being Kiwis, and not averse to butchering Maori words, they abbreviated the name further and, amongst farmers at least, it is now almost universally known as “Toot”.
The early settlers lost large numbers of animals to Toot poisoning. All parts of the plant are poisonous except for the flesh of the fruit. Within the fruit, however, there are fine seeds, which are poisonous. So, although the Maoris made a drink from the fruit and the settlers compounded a wine, there was some risk attached to the process. Canon Stack related an incident during one of his travels with Bishop Harper in the mid 1800’s. Shortly after they swallowed the wine, …the Canon lost all feeling in his extremities, and could scarcely retain his seat, but felt that he must fall forward on his face. A mist appeared to come over the room, and he perceived that he was being poisoned, and must ask for an emetic. Soon, however, his feet began to tingle, and the strange sensation passed. The good Bishop was similarly affected, so, judging from this case, the beverage can scarcely be recommended for general use.
There is no antidote. Our two reverends were lucky not to be subjected to the treatment given to Maori children poisoned after eating the berries, which was to smoke them over a fire of green boughs while they were constantly shaken. Even worse was the treatment favoured by stockmen: to bleed poisoned animals by cutting a cross in the roof of the mouth. Folk memories linger, and for the want of any effective treatment, this trick is still occasionally used. There is no scientific justification for it, except that it gives anxious stockmen something to do, and some animals will recover anyway – cases of “in spite of”, rather than “because of”, treatment. I wonder if some of these bush surgeons would be impressed if, when they rushed their poisoned child into hospital, the physician resorted to the same barbarity.
As with most plant poisonings, the symptoms are not very specific: excitability, convulsions, coma and death. The poisonous principle is a glycoside called tutin. I like this aspect of plant toxicology. Most plant toxins are either glycosides or alkaloids and usually little is known about them. With a little ingenuity it is possible to invent an erudite answer to those who wish to test your knowledge of plant poisons, merely by applying a little school-boy Latin. Hence the poisonous principle of Ragwort (Senecio jacobea), is jacobine; of Hemlock (Conium maculatum), coniine; of Yew (Taxus bacata), taxine. The new wave of European immigrants to Aotearoa brought these poisonous plants with them: either by accident, in contaminated pasture seed; or deliberately, as garden plants. One of the commonest causes of animal plant poisonings occurs when stock stray into gardens, or eat clippings carelessly flung over a fence. Rhododendron, laburnum, pieris, foxglove and aconite are all common introduced plants of deadly beauty.
My first encounter with a plant poison was a personal one, as a child. It involved laburnum, a plant so poisonous that throwing a stick of laburnum for your dog can prove fatal. In which case “All right Fido, just one last game” could become an accurate prophesy. I plead forgiveness for my ignorance of toxicology – I was only about five years old at the time – however, I must have been an observant child because I noticed the beautiful little “pills” in their neat seed pods under the laburnum tree in our Liverpool garden…
Children’s play often models itself on adult behaviour so, when we had finished killing each other (“Cowboys and Indians” being our unsophisticated vehicle for this indulgence), we sat down for a pretend dinner party under the shade of the tree. That’s when we commenced ‘popping’ the pills. The rest is a bit hazy. I remember vomiting and crawling to the house to raise the alarm. We all survived, but we were very lucky. Laburnum is the commonest plant poison causing death in children in Britain. What a great idea to bring it to New Zealand!
Within a given plant species the concentration of toxic chemicals may also vary between plant populations, and can be influenced by variables such as the age of the plant, the soil type or the c
limate. Hemlock is a classic example; or, if you prefer, an example from classical times. It was supposedly an extract of hemlock that was used to execute Socrates in 399 B.C. Since the toxic effects include vomiting, incoordination and convulsions and occur ‘within a few hours of ingestion’ his death may not have been the dignified and serene departure described by Plato: … and he walked about until, as he said, his legs began to fail, and then he lay on his back, according to the directions. And the man who gave him the poison now and then looked at his feet and legs; and after a while he pressed his foot hard, and asked him if he could feel; and he said, No; and then his leg, and so upwards and upwards and showed us that he was cold and stiff. And he felt then himself and said: When the poison reaches the heart, that will be the end. He was beginning to grow cold about the groin, when he uncovered his face, for he had covered himself up, and said (they were his last words) – he said: Crito, I owe a cock to Asclepius; will you remember to pay the debt? The debt shall be paid, said Crito; is there anything else? There was no answer to this question; but in a minute or two a movement was heard, and the attendants un-covered him; his eyes were set, and Crito closed his eyes and mouth. Such was the end, Echecrates, of our friend, whom I may truly call the wisest, most just, and best of all men whom I have ever known.
Plato’s description of creeping paralysis has a ring of authenticity, it matches other descriptions of the end stage of hemlock poisoning when the alkaloids paralyse the motor nerve endings and depress the central nervous system. Plato, it seems, for reasons of artistic licence, left out the initial vomiting and convulsions. The splatter deaths and gore of Hollywood would have been anathema to the Greeks, whose art required that scenes of death and suffering should be dignified by beauty.
Hemlock is common in New Zealand, and poisoning of livestock does occur, but not as commonly as would be expected. I have seen cattle snatching at plants on their way to a milking shed without obvious side-effects – so maybe we are fortunate and our plants contain less of the alkaloids that make this such a dangerous plant in other countries. This variability is perhaps why hemlock came to be regarded as unreliable for medicinal purposes, or as one early herbal described it, a naughtie and dangerous herb, and its use as such was discontinued in the nineteenth century.
Of course, many highly toxic plants have yielded useful drugs. In 1785, William Withering deduced that of the twenty ingredients in a secret family recipe to treat swollen legs (a manifestation of heart failure in humans that is rarely seen in animals), the effective element was foxglove. In the distant past of my veterinary training the most widely used drug for heart problems, usually in dogs, was digitalis – an extract from Digitalis purpurea, the common foxglove. Leaves of this poisonous plant floated mystically in glass-stoppered jars in the dusty dispensaries of a previous generation of pharmacists as Tincture of digitalis. Unfortunately, the amount of digitalis required to produce a clinically useful response in the heart muscle is close to the toxic level which induces nausea and vomiting. The trick was to hospitalise the dog for observation, and increase the daily dose until the dog started vomiting. The dose was then cut back slightly, to a level where there was no nausea. The whole process was referred to as digitalisation – a word that has rather different connotations today.
Alas, in veterinary medicine, we do not have the benefit of feedback from our patients about the effects of the drugs we give them. One man, on drinking tea made from foxglove leaves, became weak, nauseous and noticed yellow haloes around objects. This record, from Guy’s Hospital in London, has led to speculation that digitalis poisoning affected Van Gogh’s later paintings which feature haloes and a predominance of yellow. Twice he painted his physician holding a foxglove plant. If your dog is seeing yellow and painting haloes, my advice would be to consult a psychiatrist before he cuts off his ear.
More predictable synthetic derivatives of digitalis still have a place in modern medicine, but other families of more potent cardiac drugs have largely superseded even these.
Our family was governed by a diminutive presence for many years, but Pixie, once a tireless Fox Terrier, was getting grey about the gills and slowing down. She had made a major contribution to the up-bringing of our daughters, as family pets do, but was becoming increasingly breathless. Chasing games, that at one stage seemed endless for the human participants, would finish with a sulk after a couple of throws. She only fired into life if she spied a cat on her territory and, even then, after the initial, frantic pursuit, her enthusiasm for the post-chase, tail-up, victory patrols of her boundaries waned, and she would retire wearily to her window seat. She coughed, particularly at night, occasionally bringing up small amounts of froth. These are all classic signs of heart failure and I could clearly discern a murmur when I applied my stethoscope to her chest. Later we were able to see the cause with an ultrasound scanner: a lump on one of her heart valves. Her heart was no longer the efficient pump it should have been and, as a result of poor circulation, her lungs were becoming waterlogged.
The ideal solution for Pixie would have been to replace her defective heart valve – a matter of routine in human surgery, but scarcely economic for a family pet. Realistically, vets can only offer drugs to alleviate the symptoms.
Fortunately there are newer drugs, safer than digitalis. One category (ACE inhibitors) reduces the worst side effects of fluid accumulation. They gave Pixie a new lease of life. Although her heart still sounded like an old washing machine, her coughing all but vanished. She perked up considerably, and had a great quality of life for another three years thanks to the little pill we ground onto her food once a day. We tried to dampen her newly re-kindled enthusiasm for chasing cats, fearing it would be her undoing, but we were never able to reverse her psychological conditioning.
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The idea of going back to nature and using natural remedies has romantic appeal, but applying scientific principles to isolate the active ingredients and then modify and test them to maximise efficacy and safety is surely the way to go. It is more reliable, and safer, to take an asprin for a headache than to quaff a decoction of willow bark. Both contain the active anti-inflammatory, salicylic acid, but herbal remedies are always going to be less reliable because of the unpredictable concentrations of the active ingredient, and there is also the risk from cross-reactions with other toxic chemicals they contain.
An example of the misuse of “natural” products is the fad to use tea tree (Melaleuca) oil for skin infections. It has antiseptic properties, but is toxic if ingested. There have been fatalities in cats and kittens following flea treatment with the oil. Yet parents risk it on their children. A recent report in the veterinary press described a dog which became incoordinated, developed muscle tremors and was unable to walk for several hours after the oil was applied by the owners to treat a skin infection. Fortunately it recovered with supportive treatment. I fully agree with the conclusion of the vet who treated that dog: The public is eager to use ‘natural products’ without any testing for toxicity, let alone efficacy. The lesson here is obviously not to assume that all things natural are without dangers.
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Caffeine and nicotine – both plant alkaloids – are natural products. Their dangers are well known, and not lessened for being natural.
Another interesting plant alkaloid is atropine. Its source is deadly nightshade (Atropa bella-donna). Atropine is widely used in ophthalmology to dilate the pupil of the eye and facilitate examination of the retina at the back of the eye. An ingenious test to diagnose deadly nightshade poisoning is to put a few drops of urine from a patient suspected of being poisoned into the eye of another animal, whose pupil will, apparently, dilate fully within 30 minutes, even in bright light. To the early physicians, who diagnosed diabetes mellitus by tasting the sweetness of their patient’s urine, this would have been a tame test, indeed.
Dilated pupils signify interest and, possibly, desire. To be the object of desire, however subliminally, puts the recipient under Aphrodite’s spel
l. Bella donna means “beautiful lady”. Italian women wishing to enhance their sex appeal formerly used extract of deadly nightshade as eye drops. This strategy was not without danger. The classic signs of deadly nightshade overdose are decidedly un-erotic: fever, flushing, dry mouth, blurred vision and hallucinations or as a well-known medical mnemonic runs: hot as a hare, red as a beet, dry as a bone, blind as a bat and mad as a hatter.
However, there is a far more insidious poison – also used as a cosmetic in historical times – which remains a common cause of poisoning in man and his animals today; and it is truly a trap for the unwary vet.
Chapter Twelve
An Ancient Toxin
A handful of calves sat around the pen. “What’s wrong with them, Tony?” I asked. Tony could have answered “Something”, because that was the message I’d received over the radio-telephone: “John, please could you go to Tony H’s? There’s something wrong with his calves.” But Tony’s actual reply was equally unhelpful.
“Ah don’t reetly know. One’s died and the rest won’t eat or drink”.
The unusual insertion of the word “rightly” and the way he pronounced it, defined Tony’s origins. He had emigrated as a young man from the wilds of Derbyshire, to the West Coast; but now he and his wife had bought a small dairy farm in Western Southland.
There sometimes seems to be a subliminal trust placed by clients on vets who share their origin or ethnicity. I’m sure that a proportion of our clients preferred to see a “fair dinkum” Kiwi vet, such as Daryl, on their farm rather than one of the Poms or the South African. Likewise, because I had heard of Buxton and been down the Blue John Cave as a child, it was axiomatic that Tony expected great things from me. I could even have played the Derbyshire card a bit stronger and talked of Isaac Walton and The Compleat Angler, but that would have been pushing my luck. Unfortunately, the more I questioned him about his calves, the more puzzling the case seemed. My specially favoured status, in Tony’s eyes, seemed under threat.
