1996 - The Island of the Colorblind

by Oliver Sacks

  Parkinson himself was a paleontologist, as well as a physician, and his 1804 book, Organic Remains of a Former World, is one of the great pioneer texts of paleontology. One wonders whether he may have partly regarded parkinsonism as an atavism, a reversion, the uncovering, through disease, of an ancestral, ‘antediluvian’ mode of function dating from the ancient past.

  Whether or not this is so of parkinsonism is arguable, but one can certainly see reversion to, or disclosure of, a variety of primitive behaviors in post-encephalitic syndromes on occasion, and in a rare condition, branchial myoclonus, arising from lesions in the brain stem. Here there occur rhythmic movements of the palate, middle-ear muscles, and certain muscles in the neck – an odd and unintelligible pattern, until one realizes that these are the only vestiges of the gill arches, the branchial musculature, in man. Branchial myoclonus is, in effect, a gill movement in man, a revelation of the fact that we still carry our fishy ancestors, our evolutionary precursors, within us.

  69 About five years ago, John became intrigued by the number of lytico-bodig patients with gaze palsies. His colleague Terry Cox, a neuro-ophthalmologist, confirmed this with further eye examinations and found that half of these patients also showed strange tortuous tracks in the retina (these cannot easily be seen with an ordinary ophthalmoscope, but only with indirect ophthalmoscopy – and thus would escape notice on a routine eye exam). The tracks seem to affect just the upper layer of retinal pigment, and to cause no symptoms.

  ‘This retinal pigmentary epitheliopathy,’ John said, ‘is confined to the Chamorros – it has never been observed in a Caucasian immigrant, or in Filipinos, who have lived here since the 1940s. It’s rare in anyone under fifty – the youngest person we’ve seen with it was born in 1957. It’s present in twenty percent of Chamorros over the age of fifty; but in fifty percent of those with lytico-bodig. We have been following patients who showed RPE in the early 1980s, and more than two-thirds of them have gone on to develop lytico-bodig within ten years.

  ‘The condition doesn’t seem to be progressive; it’s more like the scar of some trauma to the eye many decades ago. We wonder if it could be a marker for the lytico-bodig, something which came on at the same time as the disease – even though we are only picking it up now. We are checking now to see if there are any similar findings in patients with PSP or post-encephalitic parkinsonism.

  ‘The tracks have some resemblance to those made by the larvae of a botfly, but we don’t have any botflies on Guam. Maybe the tracks are made by the larvae of some other fly – perhaps one which transmitted a virus that caused the lytico-bodig. Or maybe it’s an effect of a toxin. We don’t yet know if it is unique to the lytico-bodig or not, or whether it is significant at all. But all these coincidences are tantalizing, and this is another thing that makes me think that the lytico-bodig could be caused by an organism, a virus – perhaps one transmitted by an otherwise unobjectionable parasite.’

  70The term ‘cynomolgus’ means, literally, ‘dog-milking.’ The Cy-nomolgi were an ancient human tribe in Libya. Why this name should be given to some macaques (which are also known as ‘crab-eating macaques’) is unclear, though John Clay suggests that a better translation might be ‘dog-suckling,’ as macaques may indeed suckle other animals.

  71There was one report in a Japanese journal in the 1920s regarding an unusually high incidence of bulbar palsy in Saipan, though it is unclear whether this could have been a manifestation of lytico. Of the fifteen cases of lytico-bodig in Saipan described by Gajdusek et al., all but two had been born before the First World War and the youngest had been born in 1929. In several cases, according to John, the parents of these patients had been born in Guam or Rota.

  72Research on cycad neurotoxicity, somewhat dormant since the 1960s, has again become very active in several places. Tom Mabry and Delia Brownson at the University of Texas at Austin are working on the relation between cycads and lytico-bodig, looking at the effect of the putative Guam neurotoxins on rat brain-cell preparations. And Alan Seawright at the (Australian) National Research Centre for Environmental Toxicity has been investigating the effects of MAM and BMAA in experimental animals.

  73Zhang and his colleagues, re-examining the geographic variation of lytico-bodig on Guam over a twenty-year period, have confirmed the very close correlation of local cycasin levels with the disease. But such ‘correlations,’ they point out, however close, do not necessarily imply a simple cause-and-effect relationship. Though there are rare forms of Alzheimer’s disease, Parkinson’s disease, and ALS with a simple Mendelian pattern, these are the exception and not the rule. Ordinary Alzheimer’s, Parkinson’s, and ALS, it seems, are complex disorders in which the actual expression of disease is contingent on a variety of genetic and environmental factors. Indeed we are now discovering, as Spencer points out, that such gene-environment interactions are involved in many other conditions. Thus a rare but terrible side effect of streptomycin – which was introduced for the treatment of tuberculosis, but caused a total and irremediable nerve deafness in some patients – has now been found to depend on the presence of a mitochondrial DNA defect that gives no hint of its existence unless streptomycin is given.

  A variety of disorders, sometimes familial but lacking the usual Mendelian patterns of inheritance, may arise, similarly, from mutations in the mitochondrial DNA. This seems to be the case in a rare syndrome in which deafness is combined with diabetes, nephropathy, photomyoclonus, and cerebral degeneration (this syndrome, or a very similar one, was originally described in 1964 by Herrmann, Aguilar, and Sacks). Mitochondrial DNA is transmitted only maternally, and Wiederholt and others have wondered whether, in the critical period between 1670 and 1710, when the Chamorro males were virtually exterminated and the population reduced, in effect, to a few hundred females, such a mitochondrial mutation may have arisen and spread in the generations that followed, especially in certain families. Such a mutation may have sensitized those in whom it occurred so that otherwise benign environmental agents might, in them, set off the fatal degenerative processes of lytico-bodig.

  74 Marie Stopes was born in London in 1880, showed insatiable curiosity and scientific gifts as an adolescent, and despite strong disapprobation (similar to that which delayed the entry of women into medicine at the time) was able to enter University College, where she obtained a Gold Medal and a first-class degree in botany. Her passion for paleobotany was already developing by this time, and after graduating she went to the Botanical Institute in Munich, where she was the only woman among five hundred students. Her research on cycad ovules earned her a Ph.D. in botany, the first ever given a woman.

  In 1905 she received her doctorate in science from London University, making her the youngest D.Sc. in the country. The following year, while working on a massive two-volume Cretaceous Flora for the British Museum, she also published The Study of Plant Life for Toung People, a delightful book which showed her literary power and her insight into youthful imaginations, no less than her botanical expertise. She continued to publish many scientific papers, and in 1910 another popular book, Ancient Plants. Other writings, romantic novels and poems, were also stirring in her at this time, and in A Journal from Japan she gave poignant fictional form to her own painfully frustrated love for an eminent Japanese botanist.

  By this time other interests were competing with botany. Stopes wrote a letter to The Times supporting women’s suffrage, and became increasingly conscious of how much sexually, as well as politically and professionally, women needed to be liberated. From 1914 on, though there was an overlap with palaeobotany for a few years, Stopes’s work dealt essentially with human love and sexuality. She was the first to write about sexual intercourse in a matter-of-fact way, doing so with the same lucidity and accuracy she had in her description of the fertilization of cycad ovules – but also with a tenderness which was like a foretaste of D.H. Lawrence. Her books Married Love (1918), Letter to Working Mothers (1919), and Radiant Motherhood (1920) were immensely popular at the time;
no one else spoke with quite her accent or authority.

  Later Stopes met Margaret Sanger, the great American pioneer of birth control, and she became its chief advocate in England. Contraception, Its Theory, History and Practice was published in 1923, and this led to the setting up of Marie Stopes clinics in London and elsewhere. Her voice, her message, had little appeal after the Second World War, and her name, once instantly recognized by all, faded into virtual oblivion. And yet, even in old age, her paleobotanical interests never deserted her; coal balls, she often said, were really her first love.

  75 The Copernican revolution in the sixteenth and seventeenth centuries, with its revelation of the immensity of space, dealt a profound blow to man’s sense of being at the center of the universe; this was voiced by no one more poignantly than Pascal: ‘The whole visible world is but an imperceptible speck,’ he lamented; man was now ‘lost in this remote corner of Nature,’ closed into ‘the tiny cell where he lodges.’ And Kepler spoke of a ‘hidden and secret horror,’ a sense of being ‘lost’ in the infinity of space.

  The eighteenth century, with its close attention to rocks and fossils and geologic processes, was to radically alter man’s sense of time as well (as Rossi, Gould, and McPhee, in particular, have emphasized). Evolutionary time, geologic time, deep time, was not a concept which came naturally or easily to the human mind, and once conceived, aroused fear and resistance.

  There was great comfort in the feeling that the earth was made for man and its history coeval with his, that the past was to be measured on a human scale, no more than a few score of generations back to the first man, Adam. But now the biblical chronology of the earth was vastly extended, into a period of eons. Thus while Archbishop Ussher had calculated that the world was created in 4004 B.C., when Buffon introduced his secular view of nature – with man appearing only in the latest of seven epochs – he suggested an unprecedented age of 75,000 years for the earth. Privately, he increased this time scale by forty – the original figure in his manuscripts was three million years – and he did this (as Rossi notes) because he felt that the larger figure would be incomprehensible to his contemporaries, would give them too fearful a sense of the ‘dark abyss’ of time. Less than fifty years later, Playfair was to write of how, gazing at an ancient geologic unconformity, ‘the mind seemed to grow giddy by looking so far into the abyss of time.’

  When Kant, in 1755, published his Theory of the Heavens, his vision of evolving and emerging nebulae, he envisaged that ‘millions of years and centuries’ had been required to arrive at the present state, and saw creation as being eternal and immanent. With this, in Buffon’s words, ‘the hand of God’ was eliminated from cosmology, and the age of the universe enormously extended. ‘Men in Hooke’s time had a past of six thousand years,’ as Rossi writes, but ‘those of Kant’s times were conscious of a past of millions of years.’

  Yet Kant’s millions were still very theoretical, not yet firmly grounded in geology, in any concrete knowledge of the earth. The sense of a vast geologic time filled with terrestrial events, was not to come until the next century, when Lyell, in his Principles of Geology, was able to bring into one vision both the immensity and the slowness of geologic change, forcing into consciousness a sense of older and older strata stretching back hundreds of millions of years.

  Lyell’s first volume was published in 1830, and Darwin took it with him on the Beagle. Lyell’s vision of deep time was a prerequisite for Darwin’s vision too, for the almost glacially slow processes of evolution from the animals of the Cambrian to the present day required, Darwin estimated, at least 300 million years.

  Stephen Jay Gould, writing about our concepts of time in Time’s Arrow, Time’s Cycle, starts by quoting Freud’s famous statement about mankind having had to endure from science ‘two great outrages upon its naive self-love’ – the Copernican and Darwinian revolutions. To these, Freud added (‘in one of history’s least modest pronouncements,’ as Gould puts it) his own revolution, the Freudian one. But he omits from his list, Gould observes, one of the greatest steps, the discovery of deep time, the needed link between the Copernican and the Darwinian revolutions. Gould speaks of our difficulty even now in ‘biting the fourth Freudian bullet,’ having any real, organic sense (beneath the conceptual or metaphoric one) of the reality of deep time. And yet this revolution, he feels, may have been the deepest of them all.

  It is deep time that makes possible the blind movement of evolution, the massing and honing of minute effects over eons. It is deep time that opens a new view of nature, which if it lacks the Divine fiat, the miraculous and providential, is no less sublime in its own way. ‘There is grandeur in this view of life,’ wrote Darwin, in the famous final sentence of the Origin,

  that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

  76 Karl Niklas speculates on this:

  One can only wonder at the lengths of the huge rhizomes that anchored Catamites to the ground. Interconnected by these subterranean roots, hundreds of Calamites trees actually made up single organisms, possibly the largest living things in Earth’s history.

  When I was in Australia I saw a forest of antarctic beech said to date back to the last Ice Age, and at twenty-four thousand years old to be the oldest organism on earth. It was called a single organism because all the trees were connected, and had spread by runners and offshoots into a continuous, if many trunked and many rooted, plant fabric. Recently a monstrous underground that of fungus, Armillaria bulbosa, has been found in Michigan, covering thirty acres and weighing in excess of one hundred tons. The subterranean filaments of the Michigan that are all genetically homogeneous, and it has therefore been called the largest organism on earth.

  The whole concept of what constitutes an organism or an individual becomes blurred in such instances, in a way which hardly arises in the animal kingdom (except in special cases, such as that of the colonial coral polyps), and this question has been explored by Stephen Jay Gould in Dinosaur in a Haystack.

  77 Though they are sometimes similar in appearance, ferns, palms, and cycads are unrelated and come from quite different plant groups. Indeed many of their ‘common’ features have evolved quite independently. Darwin was fascinated by such examples of convergent evolution, in which natural selection, acting at different times, on different forms, in different circumstances, might reach analogous ways of solving the same problem.

  Even so basic a feature as wood, Niklas has stressed, has arisen independently in numerous different plant families, whenever there has been a need for a light, stiff material to support an erect tree form.

  Thus tree horsetails, tree club mosses, cycads, pines, and oaks have all arrived at different mechanisms for wood formation, while tree ferns and palms, which have no true wood, have developed other ways of reinforcing themselves, using flexible but stringy stem tissue or outer roots to buttress their stems. Cycads produce a softer wood, which is not as strong, but they also reinforce their trunks with persistent leaf bases, which give them their armored appearance. Other groups, like the long-extinct Sphenophyllales, developed dense wood without ever assuming an arboreal form.

  One also sees convergent evolution in the animal kingdom, with the separate evolution of eyes, for example, in many different phyla – in jellyfish, in worms, in Crustacea and insects, in scallops, and in cuttlefish and other cephalopods, as well as in vertebrates. All of these eyes are quite different in structure, as they are different in origin, and yet, they are all dependent on the operation of the same basic genes. The study of these PAX eye-coding genes, and other genes like the homeo-box genes, which determine the morphogenesis of bodies and organs, is revealing, more radically and deeply than anyone could have suspected, the fundamental unity of all life. Richard Dawkins has recently provided an excellent discussion of the development of eyes, in particular, in his book Climbing Mount Improbable.


  78 Sir Robert Schomburg described his great excitement on finding Victoria regia:

  It was on the first of January 1837, while contending with the difficulties which, in various forms, Nature interposed to bar our progress up the Berbice River, that we reached a spot where the river expanded, and formed a currentless basin. Something on the other side of this basin attracted my attention; I could not form an idea of what it might be; but, urging the crew to increase the speed of their paddling, we presently neared the object which had roused my curiosity – and lo! a vegetable wonder! All disasters were forgotten; I was a botanist, and I felt myself rewarded. There were gigantic leaves, five to six feet across, flat, with a deep rim, light green above and vivid crimson below, floating upon the water; while in keeping with this astonishing foliage, I beheld luxuriant flowers, each composed of numerous petals, which passed in alternate tints from pure white to rose and pink.

  And in the Victoria regia tank, under its giant leaves, I was later to learn, resided a strange animal, a small medusa – Craspedacusta by name. This was found in 1880 and considered to be the first-ever freshwater jellyfish (though it was subsequently realized to be the medusoid form of a hydrozoan, Limnocodium ). For many years, Craspedacusta was found only in artificial environments – tanks in botanical gardens – but is has now been found in several lakes, including Lake Fena in Guam.

  79 A favorite book of mine, one of a delightful series (‘Britain in Pictures’) published during the Second World War, was British Botanists by John Gilmour. Gilmour gives a particularly vivid and moving portrait of Joseph Hooker as a grand botanical explorer and investigator, as the son of his renowned botanist father, William Jackson Hooker (who after his years teaching in Glasgow became the first director of Kew Gardens) – and above all, in his relationship with Darwin: