Read 1996 - The Island of the Colorblind Online
Authors: Oliver Sacks
The striking similarity of tissue response in these two disorders, occurring at two different geographical locations, certainly deserves attention, not only in the clinical and pathological sense, but also from the standpoint of their familial and epidemiological features.
48
It was Freycinet’s impression that though the cycads had always been common on Guam, they had not been eaten ‘until the Spanish taught the natives how to separate its substance from the poisonous juice it contained.’ But this is a matter which has to be questioned, for in many other cultures the use of cycads and the knowledge of how to prepare and detoxify them go back to prehistoric times, as David Jones remarks in
Cycads of the World
:
Studies suggest that Australian aborigines had developed the technology for the preparation of edible foods from cycads at least 13,000 years ago…Perhaps toxic cycads were one of the first dangerous plants to be tamed by humans…Nevertheless, in view of the presence of virulent toxins, the use of cycad parts by humans as food is quite extraordinary.…Although the techniques of preparation are relatively simple…there is room for error. It is tempting to speculate on the hit or miss learning procedure which must have preceded the successful development of such a methodology.
49
Cycads, properly speaking, do not have fruits, for fruits come from flowers, and cycads have no flowers. But it is natural to speak of ‘fruits,’ for the seeds are enclosed in a brightly colored, luscious outer tunic (or sarcotesta), which resembles a greengage or plum.
50
Raymond Fosberg spent his entire professional life studying tropical plants and islands. ‘From a childhood fascination with islands,’ he remarked in a 1985 commencement address at the University of Guam:
[which] I gained from maps, in grade-school geography books, and a wonderful book, read at an early age, titled
Australia and the Islands of the Sea
, I gravitated toward islands at my first opportunity. This was a Sierra Club visit to Santa Cruz Island, off the California coast. The vision of [its] beauty…has never left me.
During the Second World War, he worked in the tropical jungles of Colombia in search of cinchona bark to provide quinine for combat troops in malarial areas and helped to export nine thousand tons of the bark. After the war, he devoted himself to the islands of Micronesia, cataloguing minutely their plant life and studying the effects of human development and the introduction of alien species upon the vulnerable habitats of islands with their native flora and fauna.
51
Botanists now recognize more than two hundred cycad species and eleven genera – the newest genus,
Chigua
, was discovered in Colombia in 1990 by Dennis Stevenson of the New York Botanical Garden.
52
Cycas revoluta
is sometimes called the sago palm (or king sago), and
C. circinalis
the false sago palm (or queen sago). The word ‘sago’ is itself a generic one, referring to an edible starchy material obtained from any plant source. Sago proper, so to speak (such as English children in my generation were brought up on), is obtained from the trunks of various palms (especially
Metroxylon
), but it also occurs in the stems of cycads, even though they are botanically quite different. The male trunks of
C. revoluta
contain about fifty percent starch, the female ones about half this. There is also a good deal of starch in their seeds – and the seeds, of course, are replenishable, whereas harvesting of the trunk kills the entire plant.
Similar considerations apply to ‘arrowroot,’ which, properly speaking, is obtained from the rootstock of the arrowroot,
Maranta
, but is also extracted from other plants, including the cycad
Zamia
. The Seminole Indians in Florida had long made use of the
Zamia
(or koonti) which grew wild there, and in the 1880
s
a substantial industry was set up, producing twenty tons or more of ‘Florida arrowroot’ annually, for use in infant foods, biscuits, chocolates, and spaghetti. The industry closed down in the 1920
s
, after overharvesting the cycad almost to extinction.
53
The consumption of this sake prepared from C. revoluta, David Jones remarks,
…is almost as deadly as a game of Russian roulette, since it is slightly poisonous and occasionally a potent batch kills all who partake.
It would go well, one feels, with a meal of puffer fish, or fugu.
54
Georg Rumpf (known to posterity as Rumphius), already a passionate naturalist and botanist in his twenties, enlisted with the Dutch East India Company and set sail for Batavia and the Moluccas in 1652. In the following decade he travelled widely in Southeast Asia, spending much time on the Malabar coast of India, where in 1658 he documented a new plant – this was the first cycad ever described, and the one which Linnaeus, a century later, was to call
Cycas circinalis
, and to take as the cardinal ‘type’ of all cycads. A few years later, Rumphius was appointed assistant to the Dutch governor of Ambon, in the Moluccas, where he embarked on his magnum opus, the
Herbarium Amboinensis
, describing 1,200 species of plants peculiar to Southeast Asia.
Though stricken by blindness in 1670, he continued his work, helped now by sighted assistants. H.C.D. de Wit, in a 1952 address on Rumphius at the Hortus Botanicus in Amsterdam (on the two hundred and fiftieth anniversary of Rumphius’ death) described in detail his labors on the
Herbarium
, which were to take forty years and were punctuated by a relentless series of travails, including the death of his wife and daughter:
It was the 17
th
of February, 1674. In the gathering dusk Mrs. Rumpf and her youngest daughter went for a visit to a Chinese friend to look at the Chinese New Year celebrations, a colourful procession through the streets, to be held later in the evening. They saw Rumphius [who was by now completely blind] passing by to take some air. Some minutes later a disastrous earthquake destroyed the larger part of the town.
Both women were killed by collapsing walls.
Rumphius returned to work on his manuscript, but in 1687 a calamitous fire burned the town of Amboina to the ground, destroying his library and all his manuscripts. Still undaunted, and aided by his remarkable abilities and determination, he began rewriting the
Herbarium
, and the original copy of the first six books finally started on its way to Amsterdam in 1692, only to be lost when the ship carrying it was sunk. (Fortunately, the governor-general of Batavia, Cam-phuys, had taken the precaution of having Rumphius’ manuscript copied before shipping it on to Holland.) Rumphius continued working on the last six volumes, but suffered another setback when sixty-one colored plates were stolen from his office in Batavia in 1695. Rumphius himself died in 1702, some months after completing the
Herbarium
– but his great work was not published until the middle of the century. The final work, despite all these mishaps, contains nearly 1,700 pages of text and 700 plates, including half a dozen magnificent plates of cycads.
55
Sidney Parkinson, the artist who voyaged on the
Endeavour
with Cook, described the plants they encountered:
Of vegetables we found…Cicas circinalis, the kernels of which, roasted, tasted like parched peas; but it made some of our people sick, who ate it: of this fruit, they make a kind of sago in the East Indies.
Cycas circinalis
does not occur in Australia, and the cycad which Cook’s crew encountered there, David Jones suggests, was probably the native
C. media
.
56
Lathyrism is a form of paralysis long endemic in parts of India, where it is associated with eating the chickling or grass pea,
Lathyrus sativus;
a little lathyrus does no harm, but sometimes it is the only food available – and then the hideous choice is to be paralyzed or starve.
It was similar, in some ways, with the ‘jake paralysis’ which paralyzed tens of thousands of Americans during Prohibition. Driven to seek some source of alcohol, these unfortunates turned to a readily available extract of Jamaica ginger (or ‘jake’), not knowing it contained large quantities of a poison (later found to be a toxic organophospho-rus compound) which could lead to paralysis. (My own research, as a student, was an attempt to elucidate its mechanism of action, using chickens as experimental animals.)
The Minamata Bay paralysis first became apparent in the mid-1950
s
, in Japanese fishing villages surrounding the bay. Those affected would first become unsteady, tremulous, and suffer various sensory disturbances, going on (in the worst cases) to become deaf, blind, and demented. There was a high incidence of birth defects, and domestic animals and seabirds seemed affected too. The local fish fell under suspicion, and it was found that when they were fed to cats, they indeed produced the same progressive and fatal neurological disease. Fishing was banned in Minamata Bay in 1957, and with this the disease disappeared. The precise cause was still a mystery, and it was only the following year that it was observed by Douglas McAlpine that the clinical features of the disease were virtually identical to those of methyl mercury poisoning (of which there had been isolated cases in England in the late 1930
s
). It took several more years to trace the toxin back to its source (Kurland, among others, played a part here): a factory on the bay was discharging mercuric chloride (which is moderately toxic) into the water, and this was converted by microorganisms in the lake to methyl mercury (which is intensely toxic). This in turn was consumed by other microorganisms, starting a long ascent through the food chain, before ending up in fish, and people.
57
That lytico or bodig can remain almost stationary for years in this way is utterly unlike the relentless progression of classic Parkinson’s disease or ALS, but such an apparent halting of the disease process was sometimes seen in post-encephalitic parkinsonism or amyotrophy. Thus one patient I have seen, Selma B., immediately following the encephalitic epidemic in 1917, developed a mild parkinsonism on one side of her body, which has remained essentially unchanged for more than seventy-five years. Another man, Ralph G., developed a gross, polio-like wasting of one arm as part of a post-encephalitic syndrome – but this has neither advanced nor spread in fifty years. (This is one reason why Gajdusek regards post-encephalitic syndromes not as active disease processes but as hypersensitivity reactions.) And yet such arrests are the exception, and lytico-bodig, in the vast majority of cases, is relentlessly progressive.
58
I was sorry to see that Darwin, who seems to love and admire every form of life, speaks (in
The Voyage of the Beagle
) of ‘the slimy disgusting Holothuriae…which the Chinese gourmands are so fond of.’ Indeed, they are not loved. Safford refers to seeing them ‘creep about like huge brown slugs.’ Jack London, in
The Cruise of the Snark
, speaks of them as ‘monstrous sea-slugs’ which ‘ooze’ and ‘writhe’ beneath his feet – the only negative note for him as he skims (‘in a chromatic ecstasy’) above the Pacific reef.
59
In his history of Pacific exploration, J.C. Beaglehole speaks of three phases – the Spanish explorations of the sixteenth century, ‘animated by a mingled zeal for religion and gold’; the Dutch voyages of the seventeenth, undertaken for commercial reasons; and the final English and French ones, devoted expressly to the acquisition of knowledge – but he sees a spirit of curiosity and wonder, no less than conquest, as animating all the explorations. Certainly this was true of Antonio Pigafetta, a gentleman-volunteer who joined Magellan, ‘desirous of seeing the wonderful things of the ocean,’ and wrote the best history of the voyage. And it was true of the Dutch voyages, which took naturalists to never before explored parts of the world – thus Rumphius and Rheede, going to the Dutch East Indies in the seventeenth century, made major contributions to biological knowledge (and, specifically, provided the first descriptions and illustrations of cycads and other plants hitherto unknown in Europe). And it was especially true of Dampier and Cook, who were, in a sense, precursors of the great nineteenth-century naturalist-explorers.
But Magellan’s reputation has not fared as well. His discovery of Guam, especially, took place under very adverse circumstances. His men were starving and sick with scurvy, reduced to eating rats and the hides which kept the rigging from chafing; they had been at sea for ninety-eight days before they finally sighted land on March 6, 1521. When they anchored in Umatac Bay and went ashore, the inhabitants stole their skiff and various odds and ends. Magellan, normally temperate, overreacted in a monstrous way, taking a large party of men ashore, burning forty or fifty houses, and killing seven Chamorros. He christened Guam (and Rota) the Ladrones, the Isles of Thieves, and treated their inhabitants with cruelty and contempt. Magellan’s own death came soon afterward, at the hands of a crowd of infuriated natives he had provoked in the Philippines. And yet Magellan should not be judged entirely by his actions in the final months of his life. For his conduct up to this point had been both moderate and masterly, in his handling of sick, angry, impatient, and sometimes mutinous crews; in his brilliant discovery of the Strait of Magellan – and in his usually respectful feeling for the indigenous peoples he encountered. And yet, as with all the early Spanish and Portuguese explorers, a sort of zealous violence was built in – Beaglehole calls this ‘a sort of Christian arrogance,’ and feels it overcame Magellan at the end.
This arrogance seems to have been wholly absent from the admirable Pigafetta, who (though himself wounded at the time of Magellan’s death) described the entire voyage – its natural wonders, the peoples they visited, the desperation of the crew, and Magellan’s own character, with its heroism, its candor, its mystical depths, its fatal flaws – with the sympathy of a naturalist, a psychologist, and a historian.