IELTS Academic Reading Practice Test 370

For much of Chinese history, a physician's knowledge came from books known as bencao — herbals that listed medicinal substances, described their properties and recorded the prescriptions in which they were used. By the sixteenth century the most respected of these works were several hundred years old, and they had been copied, expanded and annotated so often that they contradicted one another. It was into this tradition that Li Shizhen was born in 1518, in Qizhou, a town in what is now Qichun County in the central province of Hubei. His father was a doctor, and medicine was the family's livelihood.

Li Shizhen's father had higher ambitions for him. The surest route to wealth and status was the imperial examination system, and the boy was schooled in the Confucian classics from an early age. He gained the lowest degree in the hierarchy while still in his teens, but the provincial examination, which opened the way to a government career, defeated him three times. After the third failure he gave up the examination hall for the consulting room, though the habits of a scholar — careful reading, exact citation, a refusal to accept a statement merely because it was old — stayed with him.

Medicine in the Ming period was a crowded and competitive occupation, and Li Shizhen acquired a reputation for treating illnesses that others had abandoned. Practitioners ranged from literate physicians with libraries to itinerant healers selling remedies in markets, and the boundaries between the groups were loosely policed. For a time he held a post at the Imperial Medical Institute in Beijing, the body responsible for the health of the court. The work was largely administrative and he found it uncongenial; within a few years he had returned to Hubei.

Back among his books, he became convinced that the herbals needed to be rebuilt rather than merely corrected. He counted hundreds of substances that appeared in more than one category, and plants that had been given several names because no writer had compared a fresh specimen with an earlier description. More seriously, several texts recommended compounds of mercury, arsenic and lead as elixirs that would prolong life, and he had seen patients poisoned by them. A pharmacopoeia that killed the people who used it, he argued, was worse than no pharmacopoeia at all.

His method was painstaking. He is said to have consulted some eight hundred earlier works, and he added to reading a great deal of travel, walking through the mountains and river valleys of Hubei, Hunan, Jiangxi and Anhui. The journeys were made on foot and by boat over many years, and they took him to regions where the local flora differed sharply from that of his native Hubei. He questioned farmers, hunters, fishermen and woodcutters about the plants they knew, collected seeds and roots, and grew specimens in a garden so that he could watch them through the seasons. Where a description in an old text could not be matched to a living plant, he said so, rather than copying the entry forward.

The Compendium of Materia Medica, or Bencao Gangmu, was the result. It is an enormous book: fifty-two volumes, around a million words, some 1,900 medicinal substances and more than 11,000 prescriptions, illustrated with over a thousand drawings. Li Shizhen grouped his materials in sixteen sections, beginning with water, fire and earth, proceeding through minerals, herbs, grains, vegetables and fruits to trees, insects, fish, birds and animals — an arrangement that follows the natural world rather than the ailments the substances were meant to treat.

What distinguished the work from its predecessors was less its size than its habits of evidence. Each entry separates what earlier authorities had claimed from what Li Shizhen himself had observed, and where the two disagreed he usually explained which he trusted and why. He distinguished plants that had been confused for centuries, described how the potency of a drug changed with the season of collection or the method of preparation, and rejected remedies that he could not confirm. The book also took seriously substances used by country people, which polite medicine had tended to ignore.

The compilation occupied him for roughly a quarter of a century, and the text was finished in 1578. Li Shizhen did not live to see it in print. He died in 1593, and the first edition was published in Nanjing three years later, paid for by a printer who had been persuaded of its value. Further editions followed quickly.

Copies travelled widely. The work was being reprinted in Japan within a few decades, and European scholars encountered parts of it in Latin translations made by Jesuit missionaries in the seventeenth century. Its influence on European medicine was slight, but its standing in East Asia was enormous, and later Chinese pharmacopoeias were measured against it. Charles Darwin, writing about the breeding of goldfish in 1868, cited an old Chinese encyclopaedia that is generally taken to be the Compendium.

Modern readers should treat it with care. The Compendium records remedies that have since been shown to be useless, and a few that are dangerous, alongside plants whose properties later research has confirmed; its importance is botanical and historical as much as medical. What remains impressive is the principle behind it: that a claim about a medicine is worth no more than the evidence assembled to support it.

Herbal medicines are used by a large proportion of the world's population, and in many countries they remain the first treatment people turn to for everyday complaints. A single medicinal plant, however, is not one substance but a chemical crowd: a leaf may contain several hundred different molecules, of which perhaps a handful affect the body. The compound present in the greatest quantity is frequently not the one that does the work, and some of the most potent constituents occur in traces so small that early chemists overlooked them entirely.

Finding the active compound usually begins with knowledge rather than luck. Ethnopharmacology, as the field is called, starts from the plants that particular communities have used for particular complaints over long periods, on the assumption that a remedy which has survived centuries of use is more likely to contain something useful than a plant selected at random. The strategy has produced some of medicine's most important drugs: morphine from the opium poppy, quinine from the bark of South American cinchona trees, and artemisinin, extracted from the leaves of Artemisia annua, which became a standard treatment for malaria and earned its discoverer a share of the 2015 Nobel Prize in Medicine.

The plant must then be reduced to something a laboratory can handle. Material is dried and ground, and the powder is washed with solvents of increasing polarity, beginning with a non-polar liquid such as hexane and ending with water. Each solvent dissolves a different group of molecules, so the extract divides into a few crude fractions, each far simpler than the original plant but still a mixture of dozens of compounds.

The next stage is bioassay-guided fractionation. A fraction is tested in a bioassay — an experiment using cultured cells, an enzyme or a microorganism — and only those that show activity are kept. These are separated further by chromatography, a family of techniques that distributes a mixture between a moving liquid or gas and a stationary material, so that compounds travel at different speeds and emerge one after another. Each new sub-fraction is tested again, until a single active compound remains. A bioassay of this kind shows that a substance affects a particular target in the laboratory; it cannot show that the substance will survive digestion, reach the right tissue or help a patient.

Working out what the compound actually is relies on instruments. Mass spectrometry gives its molecular mass and, from the fragments it produces, clues to how its atoms are joined. Nuclear magnetic resonance spectroscopy reveals the arrangement of hydrogen and carbon atoms within the molecule. Matching the results against libraries of known compounds may identify the substance in hours, though a new compound may take months.

The chemistry of a plant is not fixed. The same species grown in two soils, or harvested in different seasons, may contain quite different quantities of a compound, and drying and storage alter it further. A study that finds a promising result in one batch may fail to reproduce it in the next, not because the science was wrong but because the plant had changed. DNA barcoding, which identifies species from short sections of genetic code, now helps manufacturers detect substitutions and misidentified material.

Regulators and manufacturers therefore speak of standardisation. A product is adjusted so that it contains a consistent amount of a named compound, often called a marker. This is a practical solution rather than a scientific one: the marker is chosen because it is easy to measure, and it may have no connection with the plant's therapeutic effect. A product can be perfectly standardised and still vary in whatever it is that helps the patient.

Safety raises separate questions. Herbal preparations are not automatically gentle, and analyses of products on sale in various countries have repeatedly found lead, arsenic or mercury at concentrations that would be unacceptable in any other medicine. Adulteration is a further risk: in the 1990s a slimming preparation used in Belgium was found to contain an Aristolochia species in place of the intended herb, and the substitution caused severe kidney damage. St John's wort, a popular remedy for low mood, speeds the breakdown of several prescribed medicines and can reduce their concentration in the blood to ineffective levels.

Clinical trials of herbal products are harder to design than trials of single drugs. A plant extract tastes and smells distinctive, which makes a convincing placebo difficult, and patients often guess which treatment they have been given. The dose is uncertain, since nobody knows which compound is responsible. Many published trials are small, short and carried out in a single country, and reviews of the field have repeatedly found the reporting to be poor. Even so, a few preparations have been tested in large trials with reasonable rigour and shown benefit, which makes the blanket claim that none of them works as indefensible as the claim that all of them do.

Current research is directed less at finding single molecules than at understanding mixtures. Metabolomics, which measures hundreds of compounds at once, is used to compare batches and to see how a preparation changes as it passes through the body, while network pharmacology attempts to map the many proteins that a mixture might affect. Whether the combination of compounds in a plant produces effects greater than the sum of its parts remains largely unresolved, and it is the question that most divides researchers who study traditional remedies from those who develop drugs.

Medicine is one of the longest courses a young person can choose. In Britain, most students enter medical school at eighteen and spend five years there, and many take an extra year to add a science degree. In the United States, medicine is a graduate course, begun only after a bachelor's degree and lasting four years. In both countries a newly qualified doctor then spends several years in supervised postgraduate training before practising independently — two years in the British foundation programme, in which trainees rotate through several specialties, and three or more in a North American residency. The total is rarely less than a decade.

The case for a shorter degree is usually made in terms of money. Clinical teaching is expensive: it requires staff, buildings and, most costly of all, the time of patients. A student on a five-year course pays fees for every one of those years and must live on borrowed money while doing so, and the state, in most wealthy countries, subsidises the whole arrangement. Shortening the course would reduce the debt that discourages applicants from poorer families, and it would release newly qualified doctors into the workforce sooner.

Underlying the financial argument is a deeper one. The habit of measuring training in years is a historical inheritance rather than a scientific finding. When Abraham Flexner reported in 1910 on the medical schools of the United States and Canada, he found a chaotic market in which some institutions were little better than diploma mills, and his recommendations — laboratory science, hospital teaching, entrance standards — led to the closure of many schools and to longer courses. The reform was necessary. But it left an assumption that more years must produce better doctors, and that assumption has rarely been examined since. In the century since, entry requirements have risen, but the number of years has remained roughly the same.

The alternative to counting years is to specify what a graduate must be able to do. In a competency-based curriculum, progress depends on demonstrating particular abilities — taking a history from a confused patient, interpreting an X-ray, breaking bad news — rather than on sitting in a lecture theatre for a fixed period. Assessments decide when a student is ready to move on, so a capable student might qualify sooner and a struggling one later. Simulation has made this more practical, since much of the early technical training can now take place on models and manikins rather than on patients. In practice, few schools have gone far down this road, partly because reliable assessment of something as nebulous as clinical judgement is difficult and expensive.

Defenders of the present system reply that patients would suffer. They have produced little evidence that a shorter course would make a doctor less safe, and the claim rests more on instinct than on data. Their stronger argument concerns what fills the later years of study.

What would be lost by removing a year is probably not the technical procedures, which can be practised in simulation, but the slow accumulation of clinical judgement. Those years are not purely educational: students also staff the wards, taking blood, writing notes and assisting in theatre. They learn by doing work that the hospital needs done, and by following a few patients over weeks rather than minutes. A student who has never watched an undiagnosed illness declare itself has not been trained to think like a physician, whatever the examinations say.

The workforce argument is weaker than it appears. Shortages have more to do with retention and distribution than with the speed at which doctors are produced: a country that trains more doctors, faster, still loses them if working conditions drive them abroad or into other careers. Nor is teaching capacity elastic. Clinical placements depend on wards, supervisors and patients, and expanding student numbers without them produces observation rather than practice. Expanding medical schools is also slow: new buildings and new teachers take years to appear.

The access argument is harder to dismiss. In England, proposals for a medical degree apprenticeship would let students train while employed by a hospital, earning a salary and paying no fees. That could widen the pool of applicants more effectively than any reduction in course length. The danger is obvious: an apprentice who spends the week fetching notes and holding retractors is cheap labour, not a student. Any such scheme needs independent inspection and a limit on service duties. Apprentices would also need the same breadth of scientific education as their university counterparts, which an employer may be reluctant to fund.

None of this means the present arrangement is defensible. The curriculum is overcrowded, the later years are often repetitive, and students are still admitted largely on the basis of school examination results and an interview. I would not cut the degree by legislation. I would require medical schools to define publicly what a graduate must be able to do, fund paid apprenticeship routes and evaluate them honestly, and spend money on keeping the doctors already trained.

The question, then, is not how many years a doctor should study but what those years are for. A shorter course that produced competent doctors would be an achievement; a long one that filled hospitals with tired students would not be defensible either. Until the profession can say what it is buying with the tenth year, the argument about length will continue to miss the point.