The Island of the Colour-blind

Title: The Island of the Colour-blind

Author: Oliver Sacks

Publisher: Picador, 2012 (First published 1996)

ISBN: 9780330526104

Pages: 361

Islands are unique in many ways. The separation guaranteed by the vastness of the sea ensures subtle changes in the language and culture of the societies inhabiting them and the mainland, even though one is an offspring of the other. Not only in sociocultural mores, the isolation brings about genetic changes in the people, animals and plants. This was observed and characterized in great detail by none other than Charles Darwin himself, by his famous voyage around the globe in HMS Beagle. The rate of changes accumulated in the genome in response to natural selection against local conditions prevailing in an island will be far greater than that on the mainland. Darwin was amazed and encouraged by the sharp evolutionary changes he observed on the Galapagos Islands, which finally led to his theory of evolution. With this in the background, we turn to this book that showcases two remote islands in the Pacific Ocean, distant thousands of miles from the continents, in which two grotesque illnesses are widely prevalent in the indigenous populations. In Pingelap, total colour-blindness is fairly common, and in Guam, a neurological disease called lytico-bodig, that exhibits symptoms of Parkinsonism and paralysis affects a section of the populace born before 1945. The author visits these islands in turn, muses on them and the probable causes. Oliver Sacks is a physician and the author of many books. Born in London and educated at Oxford, he now lives in New York where he is Professor of Neurology and Psychiatry at Columbia University.

There are many places in the world where first cousin marriage is common. In many parts of India itself, this was the norm before education and better living standards threw open the door to the outside world to those languishing in fetid superstition. Science has categorically outlined the dangers of inbreeding including widespread prevalence of genetic disorders, to mention nothing about the eventual impoverishment of the gene pool. Genetic diseases are marked often by recessive genes. Since every person possesses two sets of genes inherited from the father and mother, if one copy of the gene is healthy, the recessive gene stays dormant, without causing its harmful effects. The person with one faulty gene acts as a carrier of the disease, but the ailment itself will not be expressed in his body. When too much breeding occurs between people who are closely related, the chances of an offspring getting two copies of the recessive gene heightens. The higher than normal incidence of lunacy and other genetic defects observed in Kerala’s matrilineal society of the previous centuries may be taken note of. Pingelap Atoll’s people had to pass through a natural catastrophe that forced them to resort to inbreeding as a case of necessity. This paradise-like atoll in the middle of the Pacific vastness was hit by a huge typhoon in 1775. Most of the inhabitants perished. Out of the thousand or so dwellers, around twenty, mainly from the chief’s family, survived. The population slowly picked up over the decades, but the harmful effects of inbreeding began to tell heavily on the society’s well being. The loss of colour vision, called achromatopsia, spread among the descendants. The patients lacked all sense of colour, losing the cone cells in the retina which distinguishes colour. They depend only on the rod cells, which normal people use to see in darkness. As a result, people suffering from the disorder find it difficult to fully open their eyes in bright sunlight. This is accompanied by squint. Some semblance to normal human eyes can be generated by the liberal use of dark sunglasses. There is no cure for the disease as yet. Among the general population in other parts of the world, the rate of incidence is 1 in 30,000 whereas it is an astounding 1 in 12 in Pingelap.

Sacks presents another startling phenomenon from Guam Island in the Pacific, which falls under U.S. administration. It is a U.S. military base, with a large area of the island out of bounds for ordinary citizens. The indigenous people in this lovely tropical island is afflicted with a paralyzing sickness called lytico-bodig, somewhat related to encephalitis lethargica. The sufferers show symptoms of Parkinson’s disease or display extreme inability to move muscles or speak. The disease worsens progressively, and finally kills the patient. This disease affects only the indigenous people of the island. The cause of this ailment is still shrouded in mystery. The chapter offers an absorbing discussion on the probable causes of the disease. A strong contender is the cycad plant found in large numbers on the island, whose seeds are eaten by the people as a source of protein during droughts or famines. This was widely used during the Second World War when the island was under Japanese occupation and the local people were mercilessly starved. The highest incidence of the malady was on the people born during the war years when all they had to eat was the cycad seeds. After the island was retaken by American troops, matters returned to normalcy. There has not been a single case of lytico-bodig on the people born after the event. The cycad plant contains a neurotoxin that may be responsible for the deleterious effects, but elaborate preparation of the seed before consumption takes care of removing most of the toxin. Scientists posit that genetic predisposition and deficiency of minerals rich in calcium and aluminium may also explain the phenomenon. The last word has not been said yet.

The book is not just about diseases and cycads alone. It narrates a really adventurous travel to the beautiful Pacific islands. To reach Pohnpei, Sacks had to undergo some anxious hours in the form of a damaged plane tyre. Many of the islands in the Pacific are controlled by U.S. military. Repairs to the plane were carried out in a military base and the passengers were grudgingly allowed to stay on the island under the watchful eyes of the soldiers – a prospect equally disliked by both parties. The author gives a thrilling description of his journeys on the islands and the heaven-like beaches ideal for swimming or snorkeling. His revulsion to military bureaucracy is evident in more than one place in the book. Guam is a pretty island, but most of the prettiest beaches are under military control. Access is granted after thorough interrogation and that too, after forcing the visitors to wait for hours. But the author has not proposed exposure to radioactivity or other military-related causes for the spread of lytico-bodig.

An illuminating discussion on ancient plants like ferns and cycads that still exist in the world is also presented as a bonus. Apparently, this was facilitated by his visit to Rota Island, near Guam. This book includes a huge section of Notes that runs to about a third of the book. But they are very informative and readers don’t feel interrupted from the main story even though they have to frequently refer to these elaborate pieces of information. Nice sketches of the trees and plants are very apt to the theme. An expansive bibliography and index add to the attraction of the book. The book was first published nearly twenty years ago, and that may be why he has not included the names of those genes that cause the diseases. Not that the readers get any wiser by a cryptic acronym, but it contributes to a feeling that the malady is being studied in detail by the academia and pharma.

The book is highly recommended.

Rating: 3 Star