IELTS Academic Reading Practice Test 361

When Daniel Hale Williams qualified as a doctor in 1883, surgery was changing fast. The use of ether and chloroform in the 1840s had made it possible to operate without pain, and the antiseptic methods published by Joseph Lister in the 1860s had sharply reduced the infections that had once killed a large share of surgical patients. Surgeons were opening the abdomen to remove tumours and repair ulcers, operations that would have been unthinkable a generation earlier. The chest, however, remained a frontier. The heart was widely believed to lie beyond the reach of the knife, and the German surgeon Theodor Billroth had reportedly warned that anyone who tried to stitch a wound of the heart would forfeit the respect of his colleagues.

Williams had been born in Hollidaysburg, Pennsylvania, in 1856, one of several children. After his father died the family moved several times, and as a young man he made his way to Wisconsin, where he worked for a time as a barber before a local physician took him on as an apprentice. He went on to study at the Chicago Medical College, graduating in 1883, and stayed in the city to build a practice. His ability was noticed quickly, and he was soon teaching anatomy to medical students, a post rarely offered to a Black physician at the time.

Opportunities for a Black physician in Chicago in the 1880s were limited. Training hospitals either refused to admit Black patients or would not allow Black doctors to operate, and almost no school would accept Black women who wanted to train as nurses. Williams treated patients in their homes and in small clinics, and he began to argue that the city needed a hospital where ability, rather than skin colour, determined who could work and who could be treated. Raising the money for it was slow work.

The result was Provident Hospital, which opened in 1891 in a rented building on Chicago's South Side. It was one of the first hospitals in the United States to be interracial in both its staff and its patients. It also ran a training school for nurses that accepted Black women at a time when almost no such school would. The hospital was small and constantly short of money, but it gave Black doctors a place to operate and Black patients a place to be treated with dignity. Its wards were soon full.

The case that made Williams's reputation arrived in July 1893. A young man named James Cornish was carried into Provident with a knife wound in the chest, received in a fight. The wound was small, and at first it appeared not to be serious. Over the following day, however, his condition deteriorated: he grew weak, his pulse became rapid and his breathing laboured, and the signs suggested that blood was collecting around his heart. Williams decided to operate, even though opening a chest was still regarded as close to impossible.

Accounts of the operation differ in their details, but the outlines are clear. Williams cut through the cartilage of a rib to widen the opening, then entered the chest and found the pericardium, the tough sac that surrounds the heart, torn by the knife. He stitched the damaged tissue, cleaned the cavity and closed the wound, leaving a drain in place. Cornish survived. His recovery was slow but steady, and about seven weeks after the operation he was well enough to leave the hospital; he lived for another half-century.

Whether the operation deserves the title of the first heart surgery has been argued over ever since. Some historians have pointed out that the wound Williams closed may have been in the pericardium rather than in the muscle of the heart itself, and that the surviving records do not settle the question. In 1896 the German surgeon Ludwig Rehn reported from Frankfurt a successful repair of a stab wound to the heart, with the patient's recovery documented, and this is often cited as the first suture of the heart itself. What is not in doubt is that Williams had shown the operation to be possible.

His later career was remarkable in its own right. In 1894 he was appointed surgeon-in-chief at Freedmen's Hospital in Washington, which served the city's Black community, and there he reorganised the nursing school and demanded higher standards of hygiene and record-keeping. In 1895 he helped to found the National Medical Association, which gave Black physicians a professional body of their own at a time when the main American medical organisations excluded them. He returned to Chicago in 1898 and combined operating with teaching, and in 1913 he became a charter fellow of the American College of Surgeons.

Williams died in 1931, at Idlewild in Michigan, aged seventy-five. Hospitals and schools have carried his name. Yet his most important legacy may be the principle he demonstrated: that the heart was an organ like any other, and that skill and nerve could take surgery inside it. It would be several decades before surgeons could open the heart as a matter of routine, but the principle had been established.

More people start the day with caffeine than with any other drug. It is found in coffee, tea, chocolate and cola, and in a very wide range of energy drinks and sports products; it is also an ingredient in some painkillers, where it appears to sharpen their effect. Chemically, caffeine belongs to a family of compounds called xanthines, and it occurs naturally in the leaves, seeds and fruit of dozens of plants, which use it to deter insects and grazing animals. For human beings it is a mild stimulant, and it is almost certainly the most widely consumed psychoactive substance on earth. Unlike most such substances, it is also legal almost everywhere.

Understanding caffeine's effects begins with a molecule called adenosine. Adenosine is produced continuously in the brain and accumulates while a person is awake; as it builds up, it binds to receptors on nerve cells and slows their activity, contributing to the tiredness that eventually makes sleep irresistible. Caffeine happens to have a shape similar enough to adenosine that it can occupy the same receptors without switching them on. By sitting in the receptor and blocking adenosine, it prevents the brain from registering the signal of fatigue. The result is not extra energy but a postponed awareness of how tired the body has become.

The amount of caffeine in a drink depends on the plant, the part used and the method of preparation. A mug of filter coffee may contain around 100 milligrams, while the same volume of tea contains roughly half that; cola is lower again, and cocoa lower still. Espresso, despite its reputation, delivers a moderate dose in a very small volume, because it is brewed quickly and served in tiny cups. Energy drinks are the exception. A large can may contain 160 milligrams or more, and because these drinks are cold, sweet and consumed quickly, a teenager can take in the equivalent of several coffees within minutes.

Caffeine's reach extends well beyond the brain. It causes blood vessels to narrow, which is why it is included in some headache tablets, and it produces a small, temporary rise in blood pressure. In people who rarely drink it, it can provoke a racing pulse or a feeling of anxiety. It also stimulates the part of the brain that controls breathing, a property that is exploited in hospital units for newborn babies, where caffeine is given to premature infants who stop breathing for short periods. Its effect on the kidneys is mild: caffeine increases the production of urine slightly, but the body adapts within days, and coffee is not the dehydrating drink it is often claimed to be.

Once swallowed, caffeine passes quickly into the bloodstream and reaches the brain within about half an hour. Most of it is broken down in the liver. The work is done by an enzyme known as CYP1A2, and the speed at which that enzyme operates varies widely between individuals for genetic reasons. On average, the amount circulating in the body falls by half every five hours or so. In pregnancy the figure is much longer, and it is extended further by some medicines, including the contraceptive pill; smoking, by contrast, speeds the process up. This is why a strong coffee at nine in the evening keeps one person awake until two in the morning while another sleeps normally.

Because caffeine postpones the perception of tiredness, it can push sleep later and make it shallower. A cup drunk in the late afternoon may still be present in the body at midnight. When regular users stop, adenosine floods back to receptors that have been blocked, and the result is a familiar set of symptoms: headache, fatigue, low mood and difficulty concentrating. These usually appear within twelve to twenty-four hours of the last dose and fade over a few days. The headache is often the first sign, and it disappears within an hour or so if caffeine is taken again. Regular users may also find that a missed morning cup produces a dull ache by mid-afternoon.

Regular use also alters the brain. In response to constant blockade, nerve cells manufacture more adenosine receptors, so that the same dose of caffeine produces a smaller effect. This is tolerance, and it explains why a habitual coffee drinker may feel nothing from a cup that would keep a newcomer awake all night. Tolerance and withdrawal together lead many people to describe themselves as addicted, although researchers generally avoid the word, reserving it for substances that produce compulsive use and serious harm. Dependence on caffeine is real, in the sense that giving it up produces measurable symptoms, but it is mild beside dependence on nicotine or alcohol.

Official advice on caffeine is cautious rather than dramatic. The United States Food and Drug Administration cites 400 milligrams a day — about four cups of coffee — as an amount not generally associated with harmful effects in healthy adults. The European Food Safety Authority reached a similar conclusion and added that 200 milligrams a day appears safe during pregnancy. For children and adolescents the same body suggested a limit based on weight: 3 milligrams per kilogram per day. Sales of energy drinks, which are marketed heavily to young people, have attracted particular attention, and a number of countries now restrict them.

A walk through the corridors of almost any secondary school at break time will reveal the scale of the change. Where teenagers once carried bottles of water, many now carry brightly coloured cans containing caffeine in concentrations that would have startled their grandparents. The debate that follows usually begins with the word 'ban' and ends in disagreement, because two different questions are being confused. The first is whether caffeine is harmful to young people. The second is whether the state, or the school, should do anything about it. The evidence on the first is more nuanced than campaigners on either side admit.

Adolescence is a period of rapid change in the sleep system. At puberty the internal clock shifts later, so that the hormone melatonin, which signals the approach of sleep, is released at a later hour than in childhood. Teenagers therefore tend to fall asleep later and to need more than eight hours of sleep, while school start times require them to rise early. The consequence is a population that is chronically short of sleep. In that context, caffeine is not merely a drink but a chemical solution to a problem that caffeine itself makes worse.

How strong is the research? Most studies of teenagers and caffeine are observational: they compare what young people report drinking with what they report about sleep, mood and concentration. Such studies consistently find associations, but they cannot establish which comes first. A tired teenager who sleeps badly may drink more caffeine precisely because of the tiredness, rather than sleeping badly because of the caffeine. Laboratory experiments, in which doses are controlled and sleep is measured, are more informative but small and short. The picture is suggestive; it is not proof.

The product matters as much as the dose. A cup of tea drunk at the kitchen table delivers caffeine slowly, in a warm drink, alongside fluids, in a setting where an adult can see how much is being consumed. An energy drink is different: it is cold, sweet, heavily marketed and often drunk fast, and a single large can may hold as much caffeine as two cups of coffee. Some also contain large amounts of sugar. The pattern of use, rather than the molecule, is what makes these products a public health question.

There are serious arguments against regulation. Rules that are widely broken breed contempt for rules in general, and a minimum age for buying a can is not easy to enforce in a supermarket or a corner shop. Restrictions can also make a product more attractive precisely because it is forbidden. Meanwhile, most teenagers who drink caffeine take it in tea, coffee and chocolate, in amounts that appear to be well within the limits set by food safety authorities. On this view, the sensible course is education, not prohibition.

The arguments on the other side are, I think, stronger. Children are not simply small adults. Their brains are still developing, their sleep is already under pressure and their ability to judge long-term risk is limited. Surveys in several countries suggest that a minority of teenagers consume caffeine at levels above the recommended limit, and some of those who do report headaches, anxiety and difficulty sleeping. Schools also have a legitimate interest in what pupils consume during the day: a student who cannot concentrate in the afternoon is a problem for the whole class.

My own position follows from the distinction between products. The case for restricting energy drinks, which are designed to deliver a large dose quickly and are marketed with images of excitement and risk, seems to me strong, and a minimum age for their sale is a proportionate response. Nor am I persuaded by the objection that such a rule would be widely ignored: that is an argument for enforcing the rule, not for abandoning it. Clear labelling, stating the dose in milligrams rather than leaving consumers to guess, would help as well. A general ban on tea and coffee, by contrast, would be both impossible to enforce and faintly absurd, and it would distract attention from the products that actually cause concern.

I also part company with those who treat caffeine as the central problem. The sleep crisis among adolescents is real, and it is driven mainly by screens in the bedroom, by early school start times and by a culture that treats sleep as optional. Caffeine plays a part, but blaming it for the whole picture is a convenient way of avoiding the harder questions about how schools and families organise the day. The most useful intervention might have nothing to do with caffeine at all. Getting a can out of a school bag would achieve little if the phone stays under the pillow.

A policy that is proportionate, then, would target the products that deliver large doses to young people, require honest labels and support teaching about sleep. It would leave the ordinary cup of tea alone. Whether public opinion will move in that direction soon is impossible to say, but the direction itself seems right. The question is not whether caffeine is good or bad, but which products, sold to whom, at what dose. That is a question that can be answered with evidence, and it deserves better than a slogan.