Marcello Malpighi

Italian scientist and physician

• Born: March 10, 1628
• Birthplace: Crevalcore, near Bologna, Papal States (now in Italy)
• Died: November 29, 1694
• Place of death: Rome, Papal States (now in Italy)

Malpighi’s microscopic anatomy led him to discover the blood capillaries and demonstrate the fine structure of the lungs, thus laying the foundation for knowledge of the physiology of respiration. His other important studies were in embryology, plant anatomy, and invertebrate zoology.

Early Life

Marcello Malpighi (mahr-CHEHL-loh mahl-PEE-gee) was born in 1628, the year that William Harvey’s book on the circulation of blood was published. His parents were farmers and financially independent. Not much is known of Malpighi’s childhood. As the eldest child in the family, he had the advantages of masters and schools, and he began attending the University of Bologna on January 8, 1646, where he studied Aristotelian philosophy and met Bartolomeo Massari, a professor of anatomy. Massari soon became aware of Malpighi’s genius in science, and the latter rose from being a pupil to become an associate and close friend.

In 1649, both of Malpighi’s parents and his paternal grandmother died within a few days of each other. Since he was the eldest child, he had to interrupt his studies to settle his father’s affairs and look after his brothers and sisters. His uncle, Alessandro Alfiere Malpighi, came to his aid, and he was able to resume his studies. In 1651, Malpighi decided to study medicine and soon became a candidate for doctoral degrees in both medicine and philosophy. On April 26, 1653, both degrees were conferred. He began to practice medicine, and, toward the end of the 1655-1656 academic year, he was also a lecturer in logic at the University of Bologna.

Malpighi’s brilliance soon became apparent, but some opposition to his anti-Galenist, proexperimental ideas and his advanced views in medicine delayed his advancement. In 1656, when the Senate of Bologna established a professorship for him, he declined and accepted an appointment to the chair of theoretical medicine at Pisa, where the grand duke of Tuscany, Ferdinand II de’ Medici, had instituted a new university on a much more liberal scale. At Pisa, he became acquainted with Giovanni Alfonso Borelli, who was then professor of mathematics with an interest in biology. This association developed into a lifelong, mutually beneficial friendship.

Life’s Work

Malpighi’s true scientific career began at Pisa. By 1659, he returned again to Bologna, for his health, where he was appointed an extraordinary lecturer in theoretical medicine. He also applied himself assiduously to the investigation of microscopic anatomy. In 1662, upon Borelli’s recommendation, he was invited to fill the primary chair in medicine at the University of Messina. Four years later, he returned to Bologna, where a professorship awaited him, to lecture in practical medicine. He held this position with honor for twenty-five years.

Malpighi’s greatest contribution to science was his demonstration and description of the capillaries in the lungs. This was the first important discovery made with the aid of the microscope, and it completed Harvey’s work on the circulation of blood. These studies were described in two letters to Borelli, who published them as De pulmonibus observationes anatomicae (anatomical observations on lungs), in 1661. The lung was thought to be a fleshy organ in which blood and air freely mixed. Working at first on the lungs of dogs, Malpighi determined them to be an aggregate of membranous vesicles (alveoli) opening into the tracheobronchial tree surrounded by a capillary network. Subsequently, he investigated the lungs of frogs, which are more transparent, and demonstrated the capillary circulation as a connecting link between arteries and veins.

In his treatise De cerebro (1665; on the brain), Malpighi showed that the white matter of the central nervous system is composed of bundles of fibers, arranged in tracts connecting the brain with the spinal cord. His De viscerum structura exercitatio anatomica (1666; on the structure of viscera) contains his basic observations on microscopic mammalian anatomy. He described the histology of the liver and determined that it secreted the bile that passes through a duct to the gall bladder, which simply stores and releases it. In addition, he determined the structure and function of the kidneys.

On February 21, 1667, Malpighi married Francesca Massari, the fifty-seven-year-old sister of his former teacher Massari. In 1667, Malpighi received an invitation from Henry Oldenburg, secretary of the Royal Society in London, to correspond with the society. He gracefully accepted and was honored the following year by being elected a fellow of the society.

Malpighi’s publication on the silkworm moth, De bombyce (1669), represents the first full account of the anatomy of an insect. With his microscopes and wonderful skill, he was the first to observe the spiracles and the system of air tubes associated with them, the multichambered heart, the ventral nerve cord with its ganglia, and the silk-forming apparatus. He showed that the method of gas exchange was through the system of air tubes or tracheae, communicating with the exterior through the spiracles. He anatomized all phases of the species, and he discovered the system of excretory tubules now known as Malpighian tubules.

In the field of embryology, Malpighi published two pioneer works, Dissertatio epistolica de formatione pulli in ovo (1673; on the formation of the chick in the egg) and De ovo incubato (1675; both works in English translation in Marcello Malpighi and the Evolution of Embryology , 1966). The subject was not quite a new one; Aristotle, Harvey, and others had preceded him. He, however, enjoyed one great advantage over his predecessors; he was able to use a microscope in his studies and proceeded to produce a masterpiece, one of the best studies of the subject ever made.

In addition to the extensive studies of animal anatomy, Malpighi made the structure of the plant the subject of detailed and systematic investigations. In 1675, he published the first part of his Anatome plantarum (plant anatomy) and the second part in 1679. This, one of his largest and best monographs, earned for him acclaim, along with Nehemiah Grew, as the founder of the study of plant anatomy. Malpighi used a variety of microscopes and was able to magnify objects up to 143 times. In his investigations of stems, he found tiny ducts that possessed a spiral structure. Because of their resemblance to the tracheae of insects, he incorrectly attributed a respiratory function to them. He discovered stomata on the leaves but was unable to determine their function. In his studies of plant anatomy, Malpighi anticipated, to a certain degree, the cell theory. He described plants as being composed of separate structural units, which he called utricles.

Malpighi devoted special attention to the study of gall formations in several plants. He believed, as did nearly all scientists of his era, that these growths were spontaneous productions. He demonstrated, however, that several galls contained insect larvae. These, in some instances, he traced to an egg and onward to an adult insect. Malpighi’s description of the egg-laying apparatus (ovipositor) of the gallflies was so detailed and accurate that it enables modern entomologists to identify the species. His research on plant galls convinced him that they were produced by the action of insects. He also determined that the tubercles on the roots of leguminous plants, which were first described by him, were not caused by insects; he failed, however, to explain their origin.

On February 6, 1684, Malpighi’s house caught fire during the night and burned, resulting in the loss of many microscopes, books, research notes, and observations. In subsequent years, he suffered from nephritic and articular pains, and his health continued to decline steadily. In 1691, Malpighi reluctantly accepted an invitation from Pope Innocent XII to become the pope’s personal physician in Rome. On October 4 of that year, he left Bologna with his aged wife, a maid, and a servant and moved to Rome. Despite his new position and ill health, he continued his research. On August 11, 1694, his wife and loving companion for twenty-seven years died. Three months later, on November 29, an apoplectic stroke ended Malpighi’s life. After his death in Rome, his body was returned to Bologna to be interred with great pomp and ceremony.

Significance

Malpighi was a physician, an anatomist, an embryologist, a botanist, and a naturalist. He was comparative in his approach and among the first to make use of the microscope. His work on the lungs and the discovery of capillaries explained a major step in the process of respiration. What Harvey had made a logical necessity, Malpighi showed to be a reality. Malpighi made the first microscopic analyses of the structure of the spleen, the kidney, the liver, the tongue, the skin, and the brain. He introduced the use of stains and wax injections in his histological studies. His name has deservedly become an eponym of numerous anatomic structures. His monograph De bombyce is an original and important contribution to zoology . Malpighi’s study of the embryology of the chick was the best that had yet been made. Although he had no deep interest in causal factors and thus contributed little in this area, his descriptive embryology was masterful. His monograph on plant anatomy was so important for botany that, with the exception of Grew’s work, which readily admits Malpighi’s priority in several areas, it was not surpassed by a single production during the next 120 years.

Malpighi’s career at the University of Bologna is a contrast to that of the scholars who worked at Padua. Bologna was under the jurisdiction of the pope. Literature and ideas were censored, and the Inquisition was ready to investigate serious heresy. The forces of dogmatism were so powerful that anatomical demonstrations and microscopic proof were inadequate to enlighten these opponents of progress. Malpighi, as one who dared to combat the ancient ideas, was confronted with much hostility, yet he triumphed and was recognized as one of the greatest scientists of the seventeenth century.

Bibliography

Adelmann, Howard B. Marcello Malpighi and the Evolution of Embryology. 5 vols. Ithaca, N.Y.: Cornell University Press, 1966. A monumental and definitive work that highlights the major controversies and publications of Malpighi’s career and interprets his role in the evolution of embryology.

Cole, F. J. A History of Comparative Anatomy from Aristotle to the Eighteenth Century. London: Macmillan, 1949. Reprint. New York: Dover, 1975. An excellent presentation of the works of notable comparative anatomists, including Malpighi.

Foster, Michael. Lectures on the History of Physiology During the Sixteenth, Seventeenth, and Eighteenth Centuries. Cambridge, England: Cambridge University Press, 1901. Nine lectures presenting specific highlights in the history of physiology. Lecture 5 is a superb presentation of Malpighi’s life and work, with translations of some of his writings.

Locy, William A. The Growth of Biology. New York: Henry Holt, 1925. Contains a well-balanced presentation on Malpighi, with valuable information on his personal qualities, education, university positions, honors received, and research.

Meli, Domenico Bertoloni, ed. Marcello Malpighi: Anatomist and Physician. Florence, Italy: L. S. Olschki, 1997. Collection of essays about Malpighi’s scientific work, including his use of the microscope and the medical discoveries outlined in his letters to Borelli.

Miall, L. C. The Early Naturalists, Their Lives and Work, 1530-1789. London: Macmillan, 1912. Contains biographical information on naturalists of this period, including Malpighi, who is well covered in section 5. Although all of Malpighi’s major contributions are described, his work on plant anatomy receives the most extensive coverage.

Nordenskiöld, Erik. The History of Biology: A Survey. Translated by Leonard Bucknall Eyre. New York: Tudor, 1928. Still the best one-volume history of the biological sciences, with an emphasis on the philosophical and medical background.

Singer, Charles. A History of Biology to About the Year 1900. New York: Abelard-Schuman, 1931. Still one of the best books on the history of biology. A brief but well-balanced account on Malpighi is given in part 2.

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