A History of Medicine

Lois N. Magner, Oliver J Kim

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781138197138
• Edition: 3
• Topic: Medicina
• Subtopic: Teoría, práctica y referencia médicas

Designed for survey courses in the field A History of Medicine presents a wide-ranging overview for those seeking a solid grounding in the medical history of Western and non-Western cultures. Invaluable to instructors promoting the history of medicine in pre-professional training, and stressing major themes in the history of medicine, this third edition continues to stimulate further exploration of the events, methodologies, and theories that have shaped medical practices in decades past and continue to do so today.

1

Paleopathology and paleomedicine

One of the most appealing and persistent myths created by our ancestors is that of a Golden Age, or a Garden of Eden, a time before the discovery of good and evil, when death and disease were unknown. But, scientific evidence—meager, fragmentary, and tantalizing though it often is—proves that disease is older than humanity and was not uncommon among other species. Indeed, studies of ancient fossil remains, skeletons in museum collections, animals in zoos, and animals in the wild demonstrate that arthritis is widespread among a variety of medium- and large-sized mammals. Modern diagnostic imaging techniques have revealed tumors and bone fractures in fossilized remains. Evidence of infection has been found in the bones of prehistoric animals and, recently, genomic studies have identified specific pathogens in mummies and other well-preserved human remains.

Understanding the pattern of disease and injury that afflicted our earliest ancestors requires the perspective of the paleopathologist. Sir Marc Armand Ruffer, one of the founders of paleopathology, defined paleopathology as the science of the diseases that can be demonstrated in human and animal remains of ancient times. Paleopathology provides information about health, disease, diet, nutritional status, death, environment, and culture in ancient populations.

In Descent of Man and Selection in Relation to Sex (1871), Charles Darwin argued that human beings, like every other species, evolved from previous forms of life by means of natural selection. Human beings, Darwin concluded, descended from an ancestral species related to that of chimpanzees and gorillas, our closest relatives among the great apes. Humans apparently originated in Africa and migrated to Europe, Asia, and Polynesia by pathways that are being clarified by new scientific techniques.

The fossilized remains of human ancestors provide valuable clues to the past, but such fossils are rare and usually incomplete. In South Africa, in 1925, Raymond Dart discovered a skull that appeared to be a transitional form between apes and humans. Dart called the new species Australopithecus africanus (South African ape-man). After many years of controversy, Dart’s work was confirmed by scientists who discovered remarkable fossils at other sites in Africa.

Paleoanthropology is a field in which new discoveries inevitably result in the reexamination of previous findings and great debates rage over the identification and classification of bits of bones and teeth. Unfortunately, the environment in which ancient remains were buried can lead to confusion and misdiagnoses. For example, because the chemical salts in bones are quite soluble in water, soil conditions that are conducive to leaching out calcium can cause changes in bones that might lead to a pseudo-diagnosis of osteoporosis. Despite all the ambiguities associated with ancient remains, some traumatic events and diseases can be revealed with a fair degree of accuracy.

The temptation of Adam and Eve in the Garden of Eden. (From The New York Public Library.)

Insights from different disciplines, including archeology, historical geography, morphology, comparative anatomy, taxonomy, molecular biology, and genomic studies have enriched our understanding of human evolution. Changes in DNA, the archive of human genealogy, have been used to construct tentative family trees, lineages, and possible patterns of early migrations.

The Paleolithic Era, or Old Stone Age, when the most important steps in cultural evolution occurred, coincides with the geological epoch known as the Pleistocene, or Great Ice Age, which ended about 10,000 years ago with the last retreat of the glaciers. Early humans are generally thought of as hunter-gatherers, that is, opportunistic omnivores, who learned to make tools, build shelters, carry and share food, and create uniquely human social structures. A more realistic but less romantic version of the way early humans lived would note that they also scavenged carcasses of animals that died a natural death or were temporarily left unattended by predators. Although Paleolithic technology is characterized by crude tools made of bone and chipped stones and the absence of pottery and metal objects, the people of this era produced the dramatic cave paintings at Lascaux, France, and Altamira, Spain. Presumably, they also produced useful inventions that were fully biodegradable and, therefore, left no traces in the fossil record. The weapons used by hunters were more likely to survive than the implements used to gather the grains, fruits, nuts, vegetables, insects, and small animals that probably constituted the more reliable component of the Paleolithic diet. Women, who presumably were the gatherers, would have needed digging sticks and sacks to carry food stuffs, especially when encumbered by infants and children.

The transition to a new pattern of food production through farming and animal husbandry is known as the Neolithic Revolution. People of the Neolithic or New Stone Age developed crafts, such as basket-making, pottery, spinning, and weaving. Although no art work of this period seems as spectacular as the Paleolithic cave paintings in France and Spain, Neolithic people produced interesting sculptures, figurines, and pottery.

While archeologists and anthropologists were once obsessed with the when and where of the emergence of an agricultural way of life, they have become increasingly curious about the how and why. Nineteenth-century anthropologists tended to classify human cultures into a series of ascending, progressive stages marked by the types of tools manufactured and the means of food production. Since the 1960s, new analytical techniques have made it possible to test hypotheses about environmental and climatic changes and their probable effect on the availability of food sources. Scientists are also exploring changes in the human genome that apparently occurred after agriculture was established. Preliminary clues suggest genetic changes that ultimately affected height, digestion, the immune system, and other traits. Indirect evidence of these alterations has been uncovered by studying the genomes of living people from different parts of the world, but new approaches will make it possible to see genomic changes as they occurred over thousands of years. Like the invention of the microscope and the telescope, the introduction of genomic techniques has had a transformative effect that makes it possible to see surprising new worlds.

Recent studies of the origins of agriculture suggest that it was widely adopted between 10,000 and 2,000 years ago. When comparing the health of foragers and settled farmers, paleopathologists generally find that dependence on a specific crop resulted in populations that were less well-nourished than hunter-gatherers, as indicated by height, robustness, dentition, and so forth. Therefore, when the idea of “progressing” from hunting to agriculture is subjected to critical analysis rather than accepted as inevitable, the causes of the Neolithic transformation are not as clear as previously assumed. Given the fact that hunter-gatherers may enjoy a better diet and more leisure than agriculturalists, prehistoric or modern, the advantages of a settled way of life are obvious only to those who are already happily settled and well fed.

In early agricultural societies, the food base became narrower, with dependence on a few or even a single crop. Thus, the food supply might have been adequate and more consistent in terms of calories, but deficient in vitamins, minerals, and essential amino acids. Domestication of animals, however, seemed to improve the nutritional status of ancient populations. Although the total human population apparently grew very slowly prior to the adoption of farming, it increased quite rapidly thereafter. Prolonged breastfeeding along with postpartum sexual prohibitions found in many nomadic societies may have maintained long intervals between births. A more sedentary lifestyle presumably led to earlier weaning and shorter birth intervals, despite the grueling labor characteristic of early agriculture.

The revolutionary changes in physical and social environment associated with the transition from the way of life experienced by small mobile bands of hunter-gatherers to that of sedentary, relatively dense populations also allowed major shifts in patterns of disease. Permanent dwellings, gardens, and fields provide convenient niches for parasites, insects, and rodents. Stored foods are likely to spoil, attract pests, and become contaminated with rodent excrement, insects, bacteria, molds, and toxins.

Lacking the mobility and diversity of resources enjoyed by hunters and gatherers, sedentary populations are at risk of crop failures that can rapidly lead to malnutrition or even starvation. Migrations and invasions of neighboring or distant settlements triggered by local famines could carry parasites and pathogens to new territories and populations. Ironically, worrying about our allegedly unnatural and artificial modern diet has become so fashionable that people in the wealthiest nations have toyed with the quixotic idea of adopting the dietary patterns of ancient humans or even wild primates. In reality, the food supply available to prehistoric peoples was likely to have been inadequate, monotonous, coarse, and unclean rather than the “pure and natural” diet that modern people with access to a globalized food supply imagine for their ancient ancestors.

Paleopathology: Methods and problems

Because direct evidence of disease among ancient humans is very limited, we will have to seek out a variety of indirect approaches to reach at least a tentative understanding of the prehistoric world. For example, studies of our closest relatives, great apes and monkeys, have shown that living in a state of nature does not mean freedom from disease. Wild primates suffer from many disorders, including arthritis, malaria, hernias, parasitic worms, and impacted teeth. Our human ancestors, the first “naked apes,” presumably experienced disorders and diseases like those found among modern primates during a lifespan that was truly “nasty, brutish, and short.” Nevertheless, prehistoric peoples learned to adapt to harsh environments, quite unlike the mythical Garden of Eden. Eventually, through cultural evolution, human beings changed their environment in unprecedented ways, even as they adapted to its demands. By the domestication of animals, the mastery of agricultural practices, and the creation of densely populated settlements, human beings also generated new patterns of disease.

Paleopathologists must use a combination of primary and secondary evidence to draw inferences about prehistoric patterns of disease. Primary evidence includes bodies, bones, teeth, and charred or dried remains of bodies found at sites of accidental or intentional human burials. Secondary sources include the art, artifacts, and burial goods of preliterate peoples, and ancient documents that describe or suggest the existence of pathological conditions. The materials for such studies are very fragmentary, and the overrepresentation of the hard parts of bodies—bones and teeth—undoubtedly distorts our portrait of the past.

The probability of arriving at an unequivocal diagnosis through the study of ancient remains is so small that some scholars insist that the names of modern diseases should never be conferred on ancient materials. Other experts have systematically cataloged ancient ailments in terms of congenital abnormalities, injury, infection, degenerative conditions, cancers, deficiency diseases, and that all-too-large category, unidentified diseases.

Another approach to studying human remains in their archeological context is called bioarcheology, a field that encompasses physical anthropology and archeology. Funerary customs, burial procedures, and environmental conditions, such as heat, humidity, and soil composition, can determine the state of preservation of human remains. Cremation, in particular, creates severe warping and fragmentation. Bodies may be buried in the ground shortly after death, covered with a mound of rocks (cairn burial), or deliberately exposed to the elements. Both nomadic and settled people might place a body on some type of scaffold as a temporary measure if the death occurred when the ground was frozen. Later, the skeletal remains could be interred with appropriate ceremonies. In some burial sites the dead might be added to old graves, causing a confusing commingling of bones. Added confusion arises from ritual mutilation of the body, the admixture of grave goods and gifts (which may include body parts of animals or grieving relatives), and distortions due to natural or artificial mummification. Burrowing animals and looters might also disturb burial sites, damaging bones and changing their distribution. Catastrophes, such as floods, earthquakes, landslides, and massacres, may provide information about a large group of individuals during one moment in time.

Despite the increasing sophistication and power of the analytical techniques employed in the service of paleopathology, many uncertainties remain, and all results must be interpreted with caution. Since the last decades of the twentieth century, scientists have exploited new methods, such as DNA amplification and sequencing, the analysis of stable isotopes of carbon and nitrogen, and scanning electron microscopy to ask questions about the health, lifestyle, and culture of ancient peoples. Scanning electron microscopy has been used to examine patterns of tooth wear and enamel defects caused by stress and growth disruption and the effect of workload on the structure of bones. Where possible, chemical investigations of trace elements extracted from ancient bones and hair can provide insights into dietary patterns and quality of life. Lead, arsenic, mercury, cadmium, copper, and strontium are among the elements that can be identified in hair.

The analysis of stable isotopes of carbon and nitrogen provides insights into bone chemistry and diet because the ratio of these isotopes found in ancient human remains suggests the relative importance of plant and animal foods in the diet. For example, when scientists determined the relative amounts of carbon 13 and nitrogen 15 in the bones of human beings living in various parts of Europe more than 20,000 years ago, the results suggested that their diet was high in fish, shellfish, and waterfowl. Analyses of the isotopes in the bones of Neanderthals, in contrast, suggested that most of their dietary proteins came from large animals. However, studies of Neanderthal teeth, especially dental plaque, suggest that they also ate a variety of plants. Moreover, Neanderthals may have cooked various plants for use as foods and medicines. The assumption that Neanderthals were strictly meat eaters was once thought to explain why they disappeared from Europe about 25,000 years ago.

The 50,000-year-old skeletal remains of at least 13 Neanderthals in a cave in Spain provided new evidence about how these prehistoric people lived. Calcified layers of plaque were found on some of the teeth. By using gas chromatography and mass spectrometry to analyze organic compounds in the plaque, investigators obtained clues about the diet of these individuals. This approach has been called archeological chemistry. Chemical evidence from fossilized teeth and biomarkers in coprolites (fossilized human feces) corroborates the hypothesis that Neanderthals cooked and ate significant amounts of plants. Dental plaque contained carbohydrates and r...