Читать книгу From Poison Arrows to Prozac - Stanley Feldman - Страница 5

Preface

The words toxins and toxicology refer to poisons and the study of poisonous substances. These words are derived from the Greek toxon, a bow, and, when it is combined with philos, loving, it gives the sport of archery its name: toxophily. How, over the course of many years, bows and arrows came to be associated with noxious substances and poisons is the starting point of this book.

It is known that, since biblical times, hunters and warriors smeared their arrows with poisonous substances to make them more deadly. The practice is mentioned in the Bible and Homer refers to its use, in the Odyssey. With the discovery of gunpowder and shot the use of bows and arrows fell into disuse in Europe and Asia. However, guns and gunpowder did not reach the continent of America until well after Christopher Columbus discovered the New World and travellers and adventurers from Europe arrived with their weapons.

When these early voyagers to the New World returned home they told horrific tales of the lethal effects of the native darts and arrows. They told of how the natives smeared the arrows with a poison that they called ‘ourari’. It was these stories that caused bows and arrows to become so closely connected in people’s minds with poisonous substances. Sir Walter Raleigh, in his Discovery of the Large, Rich and Beautiful Empire of Guiana (1596), told of the terrible agony suffered by those injured by a poisoned arrow; of the victim’s ‘staring eyes bulging out of their sockets with terror’ and of ‘bellies rendered asunder’.

They were convinced that the poison was produced by sorcery. According to their tales, it was made by a cabal of elderly women who they thought were witches. They believed it was the ritual associated with its production that gave the arrows a supernatural, magical killing power.

The story of curare

The story of curare has waited over three centuries to be told. It started with the reports about the arrow poison brought back to Europe by the explorers and adventurers who followed the Columbus trail to the New World. The belief that it had magic properties was fostered by the very secretive way in which the poison was made, involving an elaborate, semi religious ritual in the middle of the night.

They were both fascinated and terrified by the effect of the poison. They told of the mystical effects of this arrow poison called ‘ourari’ and described the spell it cast over its victims. In his first-hand account of the effect of the poison, Sir Walter Raleigh, spoke of it as ‘causing a death so horrible no man can abideth to see it’. This started the search for the secret of the poison and a means of frustrating its effect.

The discovery and taming of the arrow poison is a romantic story of exploration, self-interested curiosity, enlightened guesswork, scientific endeavour and serendipity. It is a story that spans three centuries.

It is the story of the experiments of the Abbé Felix Fontanna and Dr Brockelsby in Leiden in Holland, and of others in England. It tells of the demonstration by the famous surgeon Sir Benjamin Brodie, who showed that curare killed its victims by paralysing them and stopping them breathing. It was an experiment that did much to demystify the poison. It recounts the exploits of the eccentric English explorer and naturalist Charles Waterton, who brought large samples of the native poison to England for study. It tells of how, during his journeys in South America, he wrestled with a giant snake and rode on the back of an alligator so as to obtain specimens for his museum.

It is the story of the French physiologist Claude Bernard, who worked in Paris at the time of the Paris Commune. He is known as the father of endocrinology for describing the properties of insulin eighty years before it was actually isolated. He described cardiac catheterisation (inserting a catheter into the heart) almost a hundred years before it was used in medicine and talked of ‘maintaining the stability of the internal environment’ eighty years before the term homeostasis was introduced. He discovered how curare caused paralysis. His predictions have proved prescient. He used curare as a forensic tool to learn how the body controls the composition of the body fluids, which he foresaw as the key to life.

It tells how the English surgeon T. Spencer Wells and others used the poison to treat the convulsions of tetanus and rabies, both common diseases in Victorian times; and of how Richard Gill, an American living in Ecuador in the 1920s, saw the possibilities of using curare to relieve his painful muscle spasms, caused by a riding accident, much in the way we use Botox in pain clinics today.

Eventually, after many false starts, curare was introduced into medicine in 1942 as an adjuvant – in anaesthesia and psychiatry. Within a decade it had reduced anaesthetic mortality by almost one-third and was hailed as being as important an advance in anaesthesia as antisepsis had been in surgery. Today, it, or a synthetic copy, is used in the administration of the vast majority of anaesthetics.

Postscript

The story of curare does not end with its introduction into medicine and anaesthesia. There is an important postscript to the events described in the first part of this book, which have profoundly changed the practice of medicine and our understanding of the way the brain controls the workings of our body. It has resulted in the abandonment of the iron lung for the treatment of paralysed patients and an understanding of the importance of controlling artificial ventilation in order to bring relief to patients with many killing diseases.

It was during the process of finding out how the poison killed its victims, and the subsequent taming of the poison, so that it could be used in medicine, that important discoveries were made about the way our nervous system works. It settled, once and for all, a debate that had engaged many eminent scientists during the mid-twentieth century. The dispute centred on the various claims and counterclaims as to the manner in which the brain passes on its instructions to the body. It demonstrated the important role that chemicals, produced in the brain and nervous tissues, play in this process.

It would have been impossible for human development to have occurred without the evolution in this chemical messenger system. Without the flexibility provided by additional messenger systems the brain would not be able to meet the requirements of an increasingly sophisticated and complex lifestyle. It is through learning how curare affects these systems that the subtle changes that have occurred in these mechanisms during evolution have come to light. It is these changes that have allowed us to develop the range of responses necessary for our present lifestyle.

This new understanding has led to the development of drugs to control an excessive activity of these responses or to supplement a failing system, to perfect existing drugs and to develop new, more specific agents, with fewer side effects. It is probable that in the future it will lead to a cure for conditions such as the memory loss that occurs as we get older, Parkinson’s disease, manic and depressive states, inappropriate emotional responses and many other disabling diseases.

This story that started with the South American arrow poison is not yet complete.

In telling this story in a way that is readily understandable I have tried to reduce technical jargon to a minimum, even though this has meant omitting details that might have been more satisfying to the tyro. I am aware that I have taken some leaps of faith. I have done so freely and in doing so I have promoted my own views about the way curare works. I have done so in a Popperian way,1 aware that future research may prove them to be wrong. For these transgressions, I plead mea culpa; my excuse is that they provide a better explanation of what happens than any alternative, more conventional theory.

If I have entertained the reader with a new insight into an amazing, fascinating story, I will be satisfied. If I have occasioned him or her to look in a new light at the way the physiological processes of the body are controlled, I will have truly fulfilled the purpose of this book.

1 Karl Popper (1902–94) was an Austrian-born British philosopher who argued that scientific theories can never be proved to be true, but are tested by attempts to falsify them.