Advances in 17th-Century Medicine

Locale England and continental Europe

Date 17th century

The seventeenth century was a watershed in the evolution of medical knowledge and the practice of medicine. The development and perfection of the microscope opened new fields for the study of human anatomy and physiology, leading to greater understandings of reproduction, growth, disease, and decay

Key Figures

• Jan Swammerdam (1637-1680), Dutch anatomist and physiologist
• William Harvey (1578-1657), English physician who discovered the circulation of blood
• Antoni van Leeuwenhoek (1632-1723), Dutch lensmaker who perfected the microscope
• Francesco Stelluti (1577-1646/1652), student of Galileo who coined the term “microscope”
• Francesco Redi (1626-1697), Italian physician and poet who helped disprove spontaneous generation
• Marcello Malpighi (1628-1694), Italian physician who developed the concept of glands
• Nicolaus Steno (1638-1686), Danish physician and anatomist
• Thomas Sydenham (1624-1689), English physician credited with reviving the Hippocratic view of medicine

Summary of Event

The development of the lens arguably represents the key element in scientific discovery during the seventeenth century. While Antoni van Leeuwenhoek is generally accredited with the microscope’s perfection, it was Galileo who first developed a mechanism to observe the “small.” Galileo is correctly associated with the telescope and its use in observations of the solar system, but he also used the same technology to observe microscopic objects. Early discoveries were made by students of Galileo, including Francesco Stelluti, who was the first to publish drawings of insects based upon his microscopic observations (1630), and the one who coined the term “microscope.”

While the microscope did not originate with Leeuwenhoek, he developed it to the point that it became widely applicable in the field. Leeuwenhoek was born in Delft, Holland, in 1632, the son of a basket maker. Initially in the drapery business, by the 1650’s he became increasingly interested in the production of lenses and their application in microscopy. In 1680, he would be elected as a fellow to the Royal Society of London; many of his letters and illustrations to the society were published in 1684. Even in Leeuwenhoek’s old age, contemporaries noted the steadiness of his hands for his work.

Leeuwenhoek’s work was primarily observational. The early sources for his specimens included water, plaque scraped from his teeth, and even fecal matter. His drawings appear to depict primarily protozoa and bacteria, though Leeuwenhoek never associated his “animalcules” with disease. Indeed, the germ theory of disease would not develop for another two centuries.

Contemporary with Leeuwenhoek was Jan Swammerdam , born in 1637 and among the first to apply Leeuwenhoek’s microscope to the study of anatomy and physiology. Swammerdam is credited with the discovery of red blood corpuscles, though his ideas on their functions were primarily speculative. He studied insect anatomy mostly but also was one of the early anatomists to study the human reproductive system.

While the existence of a circulatory system was known as early as Galen in the second century, knowledge of its function remained nebulous for another fifteen hundred years. Galen understood the concept of blood vessels as well as a difference between arterial and venous blood based upon their color. In his view, however, circulation was an inherent function of arterial pumping; blood was created in the liver and was consumed by the organs.

It remained for William Harvey to provide a more modern explanation for blood circulation. First trained at Caius College in Cambridge, England, Harvey continued his medical training as a student of Italian anatomist Hieronymus Fabricius ab Aquapendente at Padua in Venice. Fabricius ab Aquapendente was a student of Italian anatomist Gabriele Falloppio, who discovered the function of what came to called the Fallopian tubes in a woman’s body. Fabricius ab Aquapendente’s discovery of valves within the venous system would later play an important role in Harvey’s work on the process of circulation. Harvey received his diploma from Padua in 1602. Returning to England, in 1607, Harvey was elected fellow of the College of Physicians, maintaining a practice that had King James I and King Charles I as clients. He also did research in both anatomy and physiology.

Harvey utilized a variety of animals in his early studies on circulation, settling on snakes because the slow beating of their hearts allowed for a more precise observation. Harvey established that the contraction of the heart drives blood through the circulatory system. He also observed that the heart rested between beats, allowing it to be “refilled.” Among other observations, Harvey noted that venous circulation occurs in a single direction: Using the heart as a pump, blood flows from arteries to veins, returning to the heart. Furthermore, by measuring the quantity of blood in an animal, Harvey demonstrated that blood is not produced continuously in the liver.

The primitive state of microscopy early in the century limited Harvey’s ability to study the connections between arteries and veins. It remained for Marcello Malpighi to discover the role of capillaries in the process. Born in Rome in 1628, ironically the same year Harvey published his work describing circulation, Malpighi earned his medical degree in 1653 from the University of Bologna. He spent much of his professional career there as a member of the medical faculty.

Malpighi is considered the father of comparative physiology, as he was among the first to utilize the microscope in the study of various systems in animals. Prior to Malpighi, physicians considered organ tissues to originate as coagulated fluids (coagulum), and hence referred to such tissue as parenchymal. Malpighi determined that such tissue is actually glandular, pockets of globular forms of cells. His observations encompassed numerous types of tissue. He discovered capillaries after observing that the lungs, for example, were composed of thin membranes with a variety of tiny vessels.

Malpighi observed similar “pockets” of cells in other tissues, including the spleen, liver, and kidneys (renal glomerulus), and was also the first to observe the layering of tissue that makes up the epidermis. Though he was a contemporary of Leeuwenhoek, Malpighi’s attention to application—to practice—distinguished him from other scientific “observers.”

Though Malpighi had discovered glands, it was the Danish anatomist Nicolaus Steno who determined how they function. Born in Copenhagen in 1638, Steno carried out his early anatomical studies at the university in that city. In 1661, while dissecting the head of a sheep, he observed the presence of excretory ducts originating from the salivary glands. The duct from the parotid (salivary) gland would be named the ductus stenonianua in his honor. Steno would continue his work in the field of anatomy, eventually discovering numerous glands and ducts in the mouth and nose.

Therapy for disease as it existed in the early seventeenth century was often a “hit or miss” phenomenon. The Aristotelian concept of “humors” as the basis for disease continued to dominate medical thought, and it often formed the basis for treatment that was as likely to kill as to cure; bleeding was a common practice. Thomas Sydenham, an English physician, is often credited with reviving the Hippocratic school of medicine, in which careful observation and “bedside manner” played an important role in diagnosis and recovery.

Sydenham received an excellent medical education at Oxford, though he came to believe clinical observation was more important than pharmacological treatments. His study of epidemics in the 1650’s formed the basis of his theories on the role played by the environment in the outbreak of disease. For example, he was the first to associate fleas with typhus. He later concluded that certain illnesses resulted from iron deficiencies. Like the Hippocratic school, Sydenham believed fever itself was dangerous for the body, and he practiced methods of cooling the body to counteract its effects. Though skeptical about the drugs of the time, Sydenham did believe quinine would be useful in treating malaria. Because he insisted on careful observations in the diagnosis of medical problems, Sydenham became known as the English Hippocrates.

The idea that living matter could arise spontaneously from nonliving material, a concept called spontaneous generation, had been accepted since the time of Aristotle. Even the Church accepted some aspects of spontaneous generation. Recipes existed for the spontaneous production of mice (wheat plus dirty underwear), and frogs and eels could be generated from mud. Worms were thought to arise spontaneously in decomposing meat, a common sight during these times before refrigeration. In 1668, Francesco Redi demonstrated that such “worms,” or maggots, arose not spontaneously but rather as a result of eggs laid by flies or other insects on the exposed food.

Redi carried out one of the earliest experiments using what are now referred to as “controls.” He set up a series of flasks, into which were placed pieces of meat. The surfaces of several of the flasks were sealed completely or overlaid with gauze, which kept insects from the meat. Flasks were also left uncovered. Redi observed that the meat placed in the uncovered flasks became contaminated with maggots, and the covered flasks were free of maggots. Later, when he placed insect eggs obtained from the fine gauze on the previously covered meat, maggots formed.

Ironically, the development of microscopy would also lend support to the belief that the generation of microscopic animalcules could still occur spontaneously. The primitive state of microscopic observation meant that while relatively large objects could be observed in liquids, smaller objects could easily be overlooked. Consequently, even Redi could be “fooled” into mistaking contaminated liquids for those that were sterile. French scientist Louis Pasteur (1822-1895) ended the controversy of spontaneous generation through his own work in microbiology.

Significance

Until the seventeenth century, medical knowledge and practice were guided by theories that originated with Hippocrates and Aristotle, and the study of anatomy was directed by the ideas of Galen. The single most important event for the century was arguably Leeuwenhoek’s perfection of the modern microscope, which made clear some of the basic structures of plants as well as animals and opened the way for the sciences of anatomy and physiology. Researchers were able to see that microscopic elements—the “small”—were the necessary links to understanding organic processes such as reproduction, growth, disease, decay, and decomposition. Human anatomy and physiology, no longer speculative, were carried into the realm of modern science.

Bibliography

Conrad, Lawrence, et al., eds. The Western Medical Tradition, 800 B.C. to A.D. 1800. New York: Cambridge University Press, 1995. Andrew Wear’s chapter, “Medicine in Early Modern Europe, 1500-1700,” is an excellent introduction to early modern medicine.

Davies, Gill. The Timetables of Medicine: An Illustrated Chronology of the History of Medicine from Prehistory to Present Times. New York: Workman/Black Dog & Leventhal, 2000. Davies provides an illustrated time line for advances in medicine, covering a period of thousands of years. The detailed content makes for fascinating reading.

Fournier, Marian. The Fabric of Life: Microscopy in the Seventeenth Century. Baltimore: Johns Hopkins University Press, 1996. Examines work in microscopy and the reasons for the microscope’s appearance in the seventeenth century.

Gest, Howard. Microbes: An Invisible Universe. Washington, D.C.: ASM Press, 2003. A history of microbiology from the time of its invention to the beginning of the twenty-first century.

McNeill, William. Plagues and Peoples. Wilmington, N.C.: Anchor, 1998. This work is primarily a sociological and geographic approach to the movement of disease through human history. McNeill follows the progression of disease as a function of human migration.

Nuland, Sherwin. Doctors: The Biography of Medicine. New York: Vintage Books, 1989. A history of medicine covering its beginnings with Hippocrates to modern times. Includes an excellent chapter on William Harvey and the context of his work.

Piccolino, Marco. “Marcello Malpighi and the Difficult Birth of Modern Life Sciences.” Endeavour 23, no. 4 (1999). Examines Malpighi’s contributions to science, including his pioneering work in microscopic medical anatomy, the composition of the human body, and the pathology of diseases.

Porter, Roy, ed. Cambridge Illustrated History of Medicine. New York: Cambridge University Press, 2001. As the title implies, this work is primarily an illustrated history, but it is a useful general history source.

Ruestow, Edward. The Microscope in the Dutch Republic. New York: Cambridge University Press, 1996. Ruestow explores the role of the microscope in the scientific discoveries of the seventeenth century. Emphasis is placed on the role of Leeuwenhoek.