Reading — 2026 May–Aug Recall Set 5

In the ancient world, the waxy grey substance we now refer to as ambergris was highly prized for its medicinal properties, and was widely used as a spice, which was believed to be an aphrodisiac when added to food or wine. Ambergris itself is pleasantly aromatic, especially when warmed, and it was also highly valued as a fixing agent in the making of perfume, since it enabled a scent to retain its fragrance for much longer than might otherwise have been possible. Most ambergris was found in the form of lumps floating on the surface of the sea, or washed up on the shores of tropical and temperate oceans. At one time, ambergris was worth its weight in gold, but there was much confusion about its origins. Ambergris was known to the Arabs as ‘ambar’ and was originally called amber in the West in the Middle Ages. This eventually led to further confusion in the popular mind between ambergris and true amber, the mineral known to mineralogists as succinite, which is actually fossilised tree resin, and generally yellow in colour. Both substances were rare and costly, and both were associated with the sea, largely because for Europeans the most common source of amber was the shores of the Baltic. In Chapter 92 of Moby Dick, the American writer Herman Melville pours scorn on those who believed the two substances to be the same: ‘Though the word ambergris is but the French compound for grey amber, yet the two substances are quite distinct. For amber, though at times found on the sea-coast, is also dug up in some far-inland soils, whereas ambergris is never found except upon the sea. Besides, amber is a hard, transparent, brittle, odourless substance, used for mouth-pieces to pipes, for beads and ornaments; but ambergris is soft, waxy, and so highly fragrant that it is largely used in perfumery.’ Moby Dick was published in 1851, by which time the mystery of the origins of ambergris had been resolved by the scientific community. In 1783, the botanist Joseph Banks, who had accompanied Captain James Cook on his voyages of discovery in the Pacific, presented a paper to the Royal Society of London by the German physician Dr Franz Xavier Schwediawer in which it was conclusively proved that ambergris came from sperm whales. In this, he was confirming an observation made in the 13th century by the great Venetian traveller Marco Polo who, while on the island of Socotra in the Indian Ocean, had witnessed a sperm whale vomiting up ambergris. But whereas Marco Polo imagined that the whale had swallowed the lump in the depths of the sea, Schwediawer showed that the origin of the material was inside the whale itself. The sperm whale is the largest of the odontocetes, or toothed whales. Males can grow up to 20 metres in length. Melville described the sperm whale as ‘the king of whales’, and his novel Moby Dick is based on the pursuit of one such creature. Sperm whales are renowned for their ability to dive to great depths, possibly as far as 3,000 metres below the surface, and for remaining underwater for periods of two hours or more in pursuit of their favourite prey, the giant squid. It is from the problems the whales have in digesting the beaks of such creatures that ambergris has its origins. The beak is sharp and irritates the whale’s lower intestine, which responds by producing a black, foul-smelling liquid. It is not clear to scientists whether this secretion should be considered a normal response by the whale’s digestive system or a pathological one, but from time to time large quantities of the liquid are vomited up by the whale. Once outside the whale’s body and exposed to air, the substance hardens, acquiring the waxy, greyish and pleasantly aromatic characteristics of ambergris. Often the beaks of squid are still found embedded in lumps of ambergris, some of which can weigh several hundred kilograms. Melville took some delight in contrasting the origins of ambergris with the high value placed upon it by refined society: ‘Who would think, then, that such fine ladies and gentlemen should regale themselves with an essence found in the inglorious bowels of a sick whale!’ Sperm whales were ruthlessly pursued by commercial whalers in the 19th and 20th centuries. In 1963-64 alone, almost 30,000 individuals were killed, and only the imposition of a ban on the hunting of sperm whales in 1984 saved the species from extinction. Ambergris was by far the most valuable product to be extracted during the processing of the whales’ carcasses, and over 90 per cent of the annual worldwide total was acquired in this way, as a by-product of commercial whaling. However, even before the ban on hunting sperm whales was imposed, the 1972 Marine Mammal Protection Act had prohibited trade in ambergris. Just as petroleum and plastic products were replacing other natural products of whaling, so ambergris was supplanted in the making of perfume by other materials, some natural and some synthetic in origin. Nevertheless, it is possible that, as sperm-whale populations recover to their former numbers in the wild, so the sight of lumps of ambergris washed ashore along the tide-line will once again become a familiar one to beach-combers the world over.

Heirloom tomatoes—varieties that have been passed down through several generations of a family because they are thought to have a particularly good flavor—are really no more 'natural' than the varieties available in grocery stores. New studies promise to restore their lost, healthy genes. A Famous for their taste, color, and organic appearance, heirloom tomatoes are favorites of gardeners and advocates of locally grown foods. The tomato enthusiast might conclude that, given the immense varieties, heirlooms must have a more diverse and superior set of genes than the tomatoes available in grocery stores, those ordinary hybrid varieties such as cherry and plum. However, their seeming diversity is only skin-deep: heirlooms are actually feeble and inbred—the defective product of breeding experiments that began hundreds of years ago, and exploded thanks to enthusiastic backyard gardeners. "The irony of all this," says Steven Tanksley, a geneticist at Cornell University, "is all that diversity of heirlooms can be accounted for by a handful of genes. There're probably no more than 10 mutant genes that create the diversity of heirlooms you see." But rather than simply proving that the myth about the heirloom's diversity is wrong, Tanksley's deconstruction of the tomato genome, along with work by others, is showing how a small berry-like fruit from the Andes became one of the world's top crops. B The cultivated tomato is a member of the nightshade family that includes New World crops such as the potato, which spread around the globe after Christopher Columbus brought them back to Spain in the 15th century. But whereas scientists have uncovered a wealth of archaeological evidence on early farming practices in the New World, the record is blank when it comes to the tomato. The modern tomato seems to have its origins in the Andes in South America and may have been domesticated in Vera Cruz, Mexico. Primitive varieties still grow throughout the Americas. All told, botanists call as many as 13 species 'tomatoes' and consider an additional four to be closely related. C One might assume that one of these known wild species became today's cultivated crop, but that's not the case: the Mother Tomato has never been found. The closest relative is the currant tomato, which, based on genetic comparisons, split from today's tomato some 1.4 million years ago. So researchers like Tanksley have to work backward, crossing tomato varieties and species in order to understand how various genes influence shape and size. Once isolated, Tanksley later inserts those genes into other tomato varieties to make his case with a dramatic transformation. D Tanksley concludes from his analyses that in their effort to make bigger, tastier, and faster-growing fruit, our ancestors ultimately exploited just 30 mutations out of the tomato's 35,000 genes. Most of these genes have only small effects on tomato size and shape, but recently Tanksley and his colleagues reported that they found a gene that increases fruit size by 50 percent. It was probably the most important event in domestication. The first written record of tomatoes—from Spain in the 1500s—confirms that this mutation, which enlarges tomatoes by producing compartments known as locules, existed back in the same yellow tomatoes that gave Italians the word pomodoro, or golden apple. Besides size, tomato farmers also selected for shape. To discover those genes, Esther van der Knaap, a Tanksley alumnus now at The Ohio State University, took a gene from one heirloom tomato and inserted it into a wild relative. She observed that, as a result, the tiny fruits became shaped like pears. E The selection of these traits has, however, affected the heirloom's hardiness. They often suffer from infections that cause the fruit to crack, split, and otherwise rot quickly. Wild plants must continuously evolve to fend off such infections, points out Roger Chetelat of the Tomato Genetics Resource Center at the University of California. But in their quest for size, shape, and flavor, humans have inadvertently eliminated defensive genes. As a result, most possess only a single disease-resistant gene. Chetelat elaborates that heirlooms' taste may have less to do with their genes than with the productivity of the plant and the growing environment. Any plant that produces only two fruits, as heirlooms sometimes do, is highly likely to produce juicier, sweeter, and more flavorful fruit than varieties that produce 100, as commercial types do. In addition, heirlooms are sold ripened on the vine, a certain way to get tastier results than allowing them to mature on the shelf. This means breeders feel confident that getting germ-beating genes back into heirlooms won't harm the desirable aspects of the fruit. Modern breeding has resuscitated grocery store tomatoes with an influx of wild genes; in the past 50 years, as many as 40 disease-resistant genes have been bred back into commercial crops. F In 1996, a tomato breeder and former Tanksley student named Doug Heath began a favorite project. After 12 years of traditional breeding with the help of molecular markers, he created a new multi-colored tomato less prone to cracking and also endowed with 12 disease-resistant genes. The original heirloom plant, Heath explains, had defective flowers, which is one reason why it produced only two fruits compared with the 30 he gets from his new variety. He claims he is also able to maintain a comparable flavor and sugar profile even on productive plants. The heirloom's defects are, after all, just an accident of a narrow breeding strategy left over from the very beginning of genetic modification.

Prior to 1960, most inquiries into pupils’ learning skills explored the relationship between factors such as children’s social background, personality or measured intelligence and their achievement in various school subjects. Studies of teachers were largely a quest for criteria of effectiveness, and numerous investigations sought links between personality or attitude and ‘success’ at teaching. By 1950, Domas and Tiedeman were able to survey 672 such studies of teacher effectiveness. Yet there was widespread disappointment with such research, partly because so little of value seemed to emerge. First of all, there was little agreement about what constituted ‘good’ teaching or who the good teachers were. Secondly, there were numerous conflicting and contradictory findings. No sooner had one investigator found a relationship which appeared to be significant, than another discovered the opposite effect. For example, in 1945, two American researchers, Rostker and Rolfe, both using standardized testing techniques and broad samples of teachers, reached exactly opposite conclusions. Rostker concluded that the intelligence of the teacher is the most important single factor conditioning teaching ability, and that there is no significant relationship between personality and teaching ability. Rolfe, however, found no correlation between intelligence and teaching efficiency: he claimed that the teacher’s personality was what produced good teaching. Another American writer, Barr (1961), summarized a massive amount of American research and underlined the chaos in the research literature on effectiveness: “Some teachers were preferred by administrators, some were liked by the pupils, and some taught in classes where there were substantial pupil gains, and generally speaking these were not the same teachers.” One of the earliest pieces of research dates from 1912, when Stevens made 100 random observations of lessons in a variety of subject areas, in order to analyze the number and nature of questions being asked by teachers. Stevens’s overall total was 64% teacher talk and 36% pupil talk, figures which are remarkably similar to a number of findings half a century later. For many years in the first half of the 20th century, so-called ‘formal’ teaching was the norm. Teachers taught their classes as a whole group, gave out information, asked questions which predominantly required factual recall, and frequently set a common written task for the children to complete in a prescribed period of time. It was hardly surprising, therefore, that one focus of classroom interaction research in the decades following Stevens’s inquiry was on the phenomenon of ‘attentiveness’. A number of studies in the 1920s and 1930s, by Morrison and others, sought relationships between the degree of attention being paid by children and the amount they subsequently appeared to have learnt. Such research was usually based on observing teachers at work, a technique which was also employed extensively by United States administrators in the 1920s and 1930s, in order to assess teachers’ competence and allocate merit payments to so-called ‘superior’ teachers. As the 1930s came to an end, it was partly the emergence of totalitarian regimes in Europe which led to a shift in interest in the United States away from attentiveness, with its emphasis on the authority of the teacher, and towards a scrutiny of authoritarianism itself. A number of people began to feel that if dictatorship were to be avoided, children must learn in school how to handle democracy. Several investigators examined the processes taking place within small discussion groups, and tried to establish superiority for discussion groups over lecture classes, but with conflicting results. The movement towards what was becoming known as child-centred education was gathering momentum, and as interest in child development increased, investigators began to discover the usefulness of direct observation and the categorization of child behavior. This was when systematic observation of teacher-pupil interaction began in earnest. Anderson (1939) studied what he called ‘domination’ and ‘integration’ amongst kindergarten children. Dominative acts by children included blaming and snatching toys, and such acts by teachers included restricting children’s activities; while children’s integrative acts included sharing facilities and playing harmoniously, and those of teachers included expanding opportunities for self-direction and co-operation. Anderson then attempted to measure what is now commonly called ‘classroom climate’. Lewin, Lippitt and White (1939 and 1943) studied the effects of different teaching styles. They arranged for three groups of five boys each to be taught in very different ways: these were labelled ‘authoritarian’, ‘democratic’ and ‘laissez-faire’. The first two of these were similar to Anderson’s concept of dominative and integrative teachers. Beginning with Withall’s work in 1949, there was much greater interest in interaction within the classroom. Withall used the term ‘social-emotional climate’ to describe the emotional tone created as a result of face-to-face interaction in groups, and, like many who followed him, concentrated his analysis of this climate on the study of teachers’ verbal behavior. Withall also made efforts towards increasing the reliability of analyses, and this important pioneering work in the development of classroom observation methodology was followed by many others during the 1950s. Partly because of the disappointing results of the teacher-effectiveness research, and partly because of the general neglect in earlier work of the variables of actual classroom behavior, the decade 1960–70 produced a large number of studies of classroom processes, based on observation of teachers at work.