Read 1996 - The Island of the Colorblind Online
Authors: Oliver Sacks
The use of cycads as food had been independently discovered in many cultures; and each had devised their own ways of detoxifying them. There had been, of course, innumerable individual accidents, especially among explorers and their crews without this cultural knowledge. Members of Cook’s crew became violently ill after eating unprepared cycad seeds at the Endeavour River in Australia, and in 1788 members of the La Perouse expedition became ill after merely nibbling the seeds of
Macroza-mia communis
at Botany Bay – the attractive, fleshy sarcotesta of these are loaded with toxic macrozamin.
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But there had never been, Whiting thought, a cultural accident, where an entire culture had hurt itself by cycad eating.
There were, however, examples of animals poisoning themselves en masse, unprotected by any ‘instinctive’ knowledge. Cattle which browse on bracken may come down with a neurological disorder which resembles beriberi or thiamine deficiency – this is caused by an enzyme in bracken which destroys the body’s thiamine. Horses in the Central Valley of California have come down with parkinsonism after eating the toxic star thistle. But the example which Whiting especially remarks is that of sheep and cattle, which are extremely fond of cycads; indeed, the term ‘addiction’ has been used in Australia, where some animals will travel great distances for the plants. Outbreaks of neurocycadism, she noted, had been recorded in Australian cattle since the mid-nineteenth century. Some animals, browsing on the fresh young cycad shoots (this would especially occur in dry seasons, when other plants had died off, or after fires, when cycads would be the first plants to reshoot new leaves) would get a brief, acute gastrointestinal illness, with vomiting and diarrhea – this, if not fatal, would be followed by complete recovery, as with acute cycad poisoning in man. But with continued browsing on the plants, neurocycadism would develop; this would begin as a staggering or weaving gait (hence the colloquial name ‘zamia staggers’), a tendency to cross the hind legs while walking, and finally complete and permanent paralysis of the hind limbs. Removing the animals from the cycads at this stage was of no use; once the staggers had set in, the damage was irreversible.
Could this, Whiting and Kurland wondered, be a model for lytico? The idea was intriguing: fadang had been a common food before the war and, during the Japanese occupation, was used in much larger quantities, as other crops were requisitioned or destroyed. After the war, fadang consumption declined sharply because of the greater availability of imported wheat and corn flour – this, it seemed to them, could provide a very plausible scenario for the disease, why it had peaked immediately following the war, and steadily declined thereafter, an incidence which ran parallel to the use of fadang.
But the cycad theory was problematic on several grounds. First, there were no other known examples, outside Guam, of a chronic human illness ascribable to the use of cycads, despite their very wide and long use throughout the world. It was, of course, possible that there was something special about the Guam cycad, or some special vulnerability to it among the Chamorros. Second, the period of decades which might elapse between exposure to the cycads and the onset of lytico-bodig, if indeed the two were connected, was something which had no precedent in poisonings of the nervous system. All known neurotoxins acted immediately or within a few weeks, the time needed to accumulate to toxic levels in the body or for neurological damage to reach critical, symptomatic levels – this was so with heavy metal poisoning, as had occurred in the notorious Minamata Bay paralysis, with the neurolathyrism in India caused by eating the toxic chickling pea, and with the neurocy-cadism in cattle.
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But these seemed quite different from a poison which, while causing no immediate effects, might lead to a progressive degeneration of particular nerve cells starting many years later. No such delayed toxic effect had ever been described – the very concept strained belief.
We set off again, to return to Umatac; John had more patients he wanted me to meet. He loved showing me patients, he said, taking me on house calls with him – I also loved this, seeing his energy, his neurological skill, and, even more, the delicate feeling, the caring, he showed for his patients. It took me back to my own growing up, when I would go out on house calls with my father, a general practitioner – I had always been fascinated by his technical skills, his elicitation of subtle symptoms and signs, his knack for making diagnoses, but also by the warm feeling which manifestly flowed between him and his patients. It was similar, I felt, with John; he too is a sort of GP – a neurological GP, an island GP – for his hundreds of patients with lytico-bodig. He is not just a physician to a group of individuals, but physician to a whole community – the community of the afflicted Chamorros and their relatives who live in Umatac, Me-rizo, Yona, Talofofo, Agat, Dededo, in the nineteen villages which are scattered over Guam.
Juan, another of John’s patients, has a very unusual form of the disease, John had told me. ‘Not like ALS, not like parkinsonism, not like any of the typical forms of lytico-bodig. What he does have is a peculiar tremor which I have never seen before in lytico-bodig – but I am sure this is the beginning of the disease in him.’ Juan was fifty-eight, very powerfully built, deeply sunburned, looked much younger than his years. His own symptoms had come on a couple of years ago, and he noticed them first when he was writing a letter. The act of writing brought on a shaking, and within a year it was no longer possible to write, at least with his right hand. But he had no other symptoms at all.
I examined him and was puzzled by the tremor. It looked nothing like the resting (‘pill-rolling’) tremor one usually sees in parkinsonism, for it came on with action or intention (which suppress the resting tremor). Nor did it resemble the ‘intention tremor’ which one may see (with incoordination and other cerebellar signs) if there is damage in the cerebellum or its connections. It resembled instead what neurologists gaily call essential or benign tremor. ‘Essential’ because it seems to arise without any demonstrable lesion in the brain, and ‘benign’ because it is usually self-limiting, responds well to medication, and does not interfere with life too much.
Usually this is the case. But there are a certain number of people who go on from such a ‘benign’ tremor to develop fullblown parkinsonism or other neurodegenerative disease. I thought of one patient of mine, an elderly woman in New York, who, when she developed such a tremor, in her seventies, was severely incommoded by it. She burst into tremor whatever she did, and could only prevent this by sitting stock-still. ‘They call it benign,’ she said, ‘what’s so benign about it?’ In her case, it was intensely malignant, not only in the way it interfered with her life, but in the fact that it proved to be the first symptom of a rare corticobasal degeneration, going on to rigidity, spasticity, and dementia, and, within two years, death.
There was no reason to suppose that Juan had anything like this. What he probably had, John felt – and I trusted his intuition – was an extremely mild form of bodig, so mild that he would probably be able to work and live independently for the rest of his life. Progressive and disabling as the lytico-bodig usually is, there are some, like Juan, who are only touched by it lightly, and who, after a sometimes rapid development of symptoms over a year or two, seem to show little further advance of the disease (though I have recently heard from John that Juan has developed some parkinsonian rigidity now).
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Had I let him, John would have driven straight on to the next patient, and the next. He was eager to show me everything in the few days I would be on Guam, and his energy and enthusiasm seemed to know no limits. But I had had enough for one day, and needed a break, needed a swim. ‘Yes, you’re right, Oliver,’ said John. ‘Let’s take a break – let’s go snorkelling with Alma!’
Alma van der Velde has a charming, sloping house, covered by vines, perhaps held together by them, surrounded by ferns and cycads, right by the water’s edge in Merizo. She herself is a water creature, who spends half her days swimming in the reef – badly arthritic, she moves painfully on land, but she is a graceful, strong, and tireless swimmer. She came to Micronesia as a young woman, fell in love with it, has never left. She has swum among these reefs daily for thirty years; she knows where to find the best chitons, cowries, and top shells, she knows the caves where octopuses hide, the underhangs of the reef where the rarest corals are found. When she is not swimming, she sits on her verandah, painting the sea, the clouds, the rocky out-croppings by the reef – or reading, or writing, completely self-sufficient. She and John are close friends, so close they hardly need to talk when they are together; they sit, they watch the waves thundering on the reef, and John is able, briefly, to forget the lytico-bodig.
Alma greeted us, and smiled when she saw I had brought my own fins and snorkel. John wanted to stay on the verandah and read; Alma and I would go to the reef together. She gave me a stick to help me walk over the shallow coral shelf with its razor-sharp branches, and then led the way – following a path which I could not have discerned, but which she clearly knew intimately, out to the clear waters beyond. As soon as the water was more than a couple of feet deep, Alma dived in, and, following her, I dived in too.
We moved past great coral canyons, with their endless forms and colors and their gnarled branches – some shaped like mushrooms, some like trees, being nibbled at by tetrodons and file-fish. Clouds of tiny zebra fish and fish of an iridescent blue swam through them, and around me, between my arms, between my legs, unstartled by my movements.
We swam through shoals of wrasse and parrot fish and damsels, and saw turkey fish, with rusty feather fans, hovering beneath us. I reached out my hand to touch one as it hovered, but Alma shook her head violently (later she told me the ‘feathers’ were quite poisonous to touch). We saw flatworms waving like tiny scarves in the water and plump polychaetes with iridescent bristles. Large starfish, startlingly blue, crawled slowly on the bottom, and spiny sea urchins made me glad my feet were protected by fins.
Another few yards and we were suddenly in a deep channel, the bottom forty feet below us, but the water so clear and transparent that we could see every detail as if it were at arm’s length. Alma made some gesture I could not understand as we swam in this channel; and then we turned back, to the shallower waters of the reef. I saw hundreds of sea cucumbers, some nearly a yard long, making their cylindrical way slowly across the ocean floor, and found these enchanting – but Alma, to my surprise, made a grimace, shook her head.
‘They’re bad news,’ she said, after we had come in and showered and were eating fresh tuna and a salad with John on the porch. ‘Bottom feeders! They go with pollution – you saw how pale the reef was today.’ Indeed, the corals were varied and beautiful, but not quite as brilliant as I had hoped, not as brilliant as they had been when I snorkelled off Pohnpei. ‘Each year it gets paler,’ Alma continued, ‘and the sea cucumbers multiply. Unless they do something, it’ll be the end of the reef.’
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‘Why did you gesture when we were in the channel?’ I asked.
‘That means it’s a shark channel – that is
their
highway. They have their own schedules and times, times I would never dream of going near it. But it was a safe time today.’
We decided to rest and read for a while, in companionable silence on the verandah. Wandering inside to Alma’s comfortable living room, I spotted a large book on her shelf entitled
The Useful Plants of the Island of Guam
, by W.E. Safford. I pulled it out – gingerly, as it was starting to fall apart. I had thought, from the title, that it was going to be a narrow, rather technical book on rice and yams, though I hoped it would have some interesting drawings of cycads as well. But its title was deceptively modest, for it seemed to contain, in its four hundred densely packed pages, a detailed account not only of the plants, the animals, the geology of Guam, but a deeply sympathetic account of Chamorro life and culture, from their foods, their crafts, their boats, their houses, to their language, their myths and rituals, their philosophical and religious beliefs.
Safford quoted detailed accounts of the island and its people from various explorers – Pigafetta, Magellan’s historian, writing in 1521; Legazpi in 1565; Garcia in 1683; and half a dozen others.
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These all concurred in portraying the Chamorros as exceptionally vigorous, healthy, and long-lived. In the first year of the Spanish mission, Garcia recorded, there were more than 120 centenarians baptized – a longevity he ascribed to the ruggedness of their constitutions, the naturalness of their food, and the absence of vice or worries. All of the Chamorros, noted Legazpi, were excellent swimmers and could catch fish in their bare hands; indeed, he remarked, they sometimes seemed to him ‘more like fish than human beings.’ The Chamorros were skilled as well in navigation and agriculture, maintained an active trade with other islands, and had a vital society and culture. Romantic exaggeration is not absent in these early accounts, which sometimes seem to portray Guam as an earthly paradise; but there is no doubt that the island was able to support a very large community – the estimates all fall between 60,000 and 100,000 – in conditions of cultural and ecological stability.
Though there were occasional visitors in the century and a half that followed Magellan’s landing, there was to be no massive change until the arrival of Spanish missionaries in 1668, in a concerted effort to Christianize the population. Resistance to this – to forced baptism, in the first place – led to savage retaliation, in which whole villages would be punished for the act of a single man, and from this to a horrifying war of extermination.
On top of this, there now came a series of epidemics introduced by the colonists – above all smallpox, measles, and tuberculosis, with leprosy as a special, slowly smoldering gift.
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And in addition to actual extermination and disease, there were the moral effects of a forced colonization and Christianization – the attempted soul murder, in effect, of an entire culture.