| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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feature The Double Life of Islands Are there more poets per square mile on islands or on continents? This study hasn't been done yet, but of four Nobel Prize winners in literature since World War I from my country of origin, Italy, three came from islands (Deledda from Sardinia, Pirandello and Quasimodo from Sicily). A certain distance from the mainland may be symbolic of a certain difference from the mainstream, a greater likelihood to inject surprise or marvel: an essential ingredient of all art. Islands are "odditoriums"--a neologism coined by Mr. Ripley of Believe It or Not!--and island communities are, as John Fowles put it in Islands, the original alternative societies. Islands are qualitatively different from continents. They are not just smaller, they are also cozier, lonelier, seemingly safer, and more eccentric. Islands are romantic or Dionysian, not classical or Apollonian. They are romantic because they are freer; more given to excesses, to idiosyncratic cravings, to forbidden fruits. No wonder the stockbroker Paul Gauguin went to an island, Tahiti, to reinvent himself as a painter. It is probably not mere coincidence that gay culture has flourished on islands. Sappho, the most prominent lesbian poet of antiquity, lived, appropriately enough, on Lesbos, an island off modern-day Turkey, and many gay cultures have flourished on islands, from Capri (the playground of emperor Tiberius and of Norman Douglas) to Key West (the winter haven of Elizabeth Bishop and of Tennessee Williams) and Fire Island (where W.H. Auden and Christopher Isherwood summered). San Francisco is almost an island, surrounded as it is on three sides by water. Similarly, Sirmione, on Lake Garda, was the beloved home of Catullus, a bisexual poet of Imperial Rome. Islands are an experiment of nature that we are just starting to understand. On one hand, by favoring mating among blood relatives, they provide fertile ground for population geneticists. On the other hand, by sheltering populations from contagion, they may throw the infectious nature of diseases into sharp relief when the shelter breaks down. We are all more or less endogamous--as we may be attracted by our opposites, but tend to marry our twin soul (and a similar face and body). The payoff is the conservation of desirable cultural and biological traits such as general intelligence, or verbal or commercial ability, and, more important in a larger perspective, the preservation of diversity. The downside is the surfacing of genetic traits which may be maladaptive when in double dose, in the homozygous state. It is the smaller inbreeding groups, of course, that tend to suffer the most from genetic diseases. Tristan da Cunha, a tiny island in the south Atlantic, illustrates the problem. Settled since the early 1800s, Tristan da Cunha has a stable population of only three hundred. For most of its history the island has had no more than ten breeding couples at any given time; four ancestors have contributed more than 60 percent of the genes of the current inhabitants. Marriage with relatives is inescapable. Little wonder that genetic disorders abound (the most severe being retinitis pigmentosa) at a frequency six times higher than in Britain. There is even a unique "Tristan" syndrome of mental dullness, deafness, "Gothic" palate, and deformed ears, which, as found in a 1961 survey, affected 36 people. Isolation and genetic bottlenecking are important in speciation. As Harvard biologist Ernst Mayr argued almost half a century ago, the accumulation of mutations which brings about a new species would hardly be possible without sheltering from genetic admixture. In a freely intermixing population, mutations still occur, of course, but the constant mixing of the genetic pool interferes with speciation, that is, with the emergence of a distinct population group that cannot interbreed with the parent species. Could a similar process take place in human culture? Are scientific revolutions and the emergence of new moral paradigms that different from speciation? It may not be a coincidence that such eccentric notions as those embodied in habeas corpus and in the Magna Carta germinated in a physical island, England, and such improbable conceits as monotheism and psychoanalysis arose in a cultural island, Judaism. Constant exposure to other people's old ideas may interfere with the mysterious process by which new ideas come to be established--just like exposure to the genes of the mother population interferes with the emergence of new species. The human species is already very homogeneous. For reasons which remain unclear (rapid recent expansion? genetic bottlenecking in the remote past?), it is much more homogeneous than the chimpanzees, our closest relatives, or other great apes. The genes of two humans on different continents are more similar than those of two gorillas in the same forest in West Africa. Modern culture has the potential to increase this homogeneity--what with the increase in mobility of individuals and populations, the globalization of marketing, and the exportation of TV programs. Heterogeneity has much to recommend it. It may facilitate the fit with an irreducibly diverse environment and provide a reservoir of genetic polymorphism from which more disparate mutants may emerge and, if need be, prevail. Islands are as paradoxical as the ideas about them are seemingly incompatible. The very same physical features that favor variance in the large framework may enforce homogeneity on the small scale. Inhabitants of island A may be more different from those of island B than two comparably sized populations on the mainland, yet the populations of each island can be dangerously homogeneous. The danger is cultural as well as biological. Aristotle observed that "inhabitants of only one kind cannot make a city," and modern research shows that they cannot make a viable island either. Another paradox is that of freedom and imprisonment, as the physical characteristics of islands make them ideal for sanctuaries as well as for prisons. From isolation to imprisonment is but a small step: few locales can beat an island as a site for maximum security prisons. And while islands may be experienced as freedom by first generation islanders--those who went to an island of their own free will--subsequent generations, aware of the world beyond, may experience the same locale as confining. Hippocrates was among the earliest of his profession to recognize the value of isolation. He plied his trade in Coos, an island off mainland Greece. And about the same time, 1000 b.c., Tiberine Island in Rome, in the middle of the river Tiber, between the Ghetto and Trastevere, was dedicated to health and medicine. It is still a hospital three thousand years later and is thought to be the site devoted to health care for the longest continuous time on Earth. Many cities have followed Rome's example and built hospitals on islands, especially communicable disease hospitals, from Venice (the Lazzaretto) to New York (Sea View, Metropolitan, and now Goldwater Memorial, Roosevelt Island). The Venice communicable disease facility was not just a hospital for the sick but also a down-at-the-heels hotel for newly arrived visitors from ports tainted by the plague. "Keep them out, but give them shelter" seems to have been the unspoken rule. The visitors were kept in the Lazzaretto for 30 days (la trentina) to allow the incubation period of most diseases to expire. For good measure the time of isolation was extended later to 40 days (quaranta in Italian, from which the word "quarantine" derives). Reverse isolation, that is, the isolation which aims to protect the isolated, also occurs on islands, mostly unintentionally. Unlike what happens on the mainland, where, as a rule, there are no effective barriers to contagion, and a communicable disease can perpetuate itself ad infinitum, on an island an infective agent may easily die out when those at risk run out. If the infective agent is reintroduced after many years, the disease often flares with unwonted intensity, because many or all the island inhabitants are susceptible. This is another island paradox. Isolation entails sheltering, protection for the short run, which may result in increased susceptibility in the long run. Moreover, as a rule, communicable diseases are often more severe in adults than in children. That's the main reason why, when an infectious disease is first introduced in a virgin population, or when it comes back after an absence of many years, it is more severe in the individual patients as well as more widespread in the community. A secondary reason for increased severity may be genetic--at least in diseases with a high mortality rate, which may select out genetically resistant individuals. Reintroduction of infectious agents after a long absence or introduction in previously virgin human groups has occurred many times accidentally and sometimes allegedly on purpose. Biologic warfare may or may not have been invented in America by early colonists giving gifts of smallpox- contaminated blankets to natives and may or may not have been used recently against the Kurds in Iraq, but, for obvious reasons, these outbreaks have not been well studied. We have excellent studies on other locales, however, most notably in the Faroe Islands. In this Danish possession in the North Sea, there was no case of measles from 1781 to 1846. Then a young Dane arrived from Copenhagen while incubating measles, and the disease spread like wildfire, as only people in their sixties or older had had a chance to become immune (in 1781 or earlier). Of the 7,782 inhabitants, about 6,000 became clinically ill and at least 102 died of the disease. The Faroe Islands have been the site of an even more interesting story in this century. If we are to believe published reports, there was no multiple sclerosis at all in the Faroes until 1945. Then the disease appeared in a near- epidemic form, abated, came back, abated again and came back again. How do we make sense of these weird happenings? A team of American neuro-epidemiologists has proposed that the disease, or rather its hypothetical precursor infection, was imported by English soldiers who were stationed on the island during World War II. The data are consistent with a limited age susceptibility (from 10 to 15 years) and a long latent period between the original infection (common) and the eventual onset of multiple sclerosis itself (rare). Whether this model holds true in its details or not, the observation of near-epidemic appearance of a disease which had been previously conspicuous in its absence is a strong argument in favor of its infectious nature, or rather of the infectious nature of its preceding disease. Attempts to use reverse isolation as a rational, thought-out attempt to protect from disease have been less successful than the fortuitous isolation of the Faroe Islands from multiple sclerosis. In the 1930s Alvin Coburn, a distinguished student of rheumatic fever, was impressed with the rarity of the disease in the Caribbean and set up a program to ship New York children who had been affected by the disease, and were therefore known to be highly susceptible to recurrences, to Puerto Rico. At that time the only way to protect children from recurrences of rheumatic fever was to isolate them in live- in institutions, preferably in the country, with only dubious results. By the end of the thirties, however, sulfonamides were used successfully to prevent recurrences of rheumatic fever, and the trip to Puerto Rico, which may or may not have been successful, became unnecessary. Ironically, in more recent years Puerto Rico has been recognized as a hotbed of rheumatic fever--but whether it was always there without being recognized, or was introduced by the ease of travel to and from the mainland brought about by the jet age remains a moot point. The optimum size for human communities has been debated at length since a wag asserted that two is company and three is a crowd. Optimum for what? For health (today or tomorrow); for wealth; for evolution, or perchance for happiness? We don't know. We do know a few discrete things, though. There is increasing evidence from ethnoarcheological research on Henderson and Pitcairn islands in Polynesia that human settlements smaller than 50 or perhaps even as large as two hundred may not be viable indefinitely if isolated. When the mutineers of HMS Bounty landed on Pitcairn in 1789, they found it uninhabited but with evidence of a former human settlement. Modern archeologists found the same on Henderson. It appears now that both islands were colonized by Polynesians from Mangareva Island, four hundred kilometers away, by a.d.1000. In time, deforestation took its toll; with no trees suitable for building boats, communication, and commerce ceased among the islands about a.d.1450. Mangareva's inhabitants survived despite savage wars and cannibalism, but the inhabitants of Henderson (about 50) and Pitcairn (a few hundred) died out after 150 years of isolation. The deleterious effects of inbreeding, or the lack of breeding lest the incest taboo be broken, may have played a role; and so may murder and cannibalism in the face of dwindling food supply caused by climate fluctuations. Aboriginal Tasmania's five thousand inhabitants managed to survive in isolation for 10,000 years but didn't thrive, in fact regressed, forsaking fishing and bone-tool manufacture. Humans are a gregarious species and a critical mass is necessary to ignite their Promethean fire. A final paradox. Conventional bombing, as in the Puerto Rican islands of Vieques and Culebra, is bad enough. But those nuclear powers which had access--France and the United States--chose islands to test nuclear devices. The islands were not always barren. But then, the people to relocate were only islanders. So before heeding James Thurber's advice, "Run, don't walk, to the nearest desert island," stop and listen. There may be peace in the islands (and especially in desert islands), but you may find yourself part of an experiment instead. Perhaps the good preacher and poet John Donne was being more prescriptive than descriptive when he wrote: "No man is an island...." Angelo Taranta is a physician and poet living in Palo Alto. |
Summer 1995
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