Lazzaro Spallanzani

Italian scientist

• Born: January 12, 1729
• Birthplace: Scandiano, Duchy of Modena (now in Italy)
• Died: February 11, 1799
• Place of death: Pavia, Cisalpine Republic (now in Italy)

Spallanzani is famous for his acute scientific observation and experimentation. He worked on problems in geology, volcanology, meteorology, chemistry, and physics, but it is his studies of infusoria, blood circulation, biological reproduction, digestion, and respiration that have proved to be of the greatest scientific significance.

Early Life

Lazzaro Spallanzani (LAHD-dzahr-oh spahl-lahnt-SAHN-ee) was born in Scandiano, northeast of the Apennines, where his father, Gianniccolò, was a prominent lawyer. During his early schooling there, his interest in astronomy earned for him the nickname “the Astrologer.” When fifteen, Spallanzani was sent to the Jesuit seminary in Reggio Emilia, where he pursued rhetoric, philosophy, and languages. In 1749, he started law studies at the University of Bologna. Spallanzani’s cousin, Laura Bassi, professor of physics and mathematics there, supervised his study of the sciences, natural history, Greek, Latin, French, and antiquities. Nature intrigued Spallanzani, and after three years his father permitted him to devote himself to the sciences.

In 1753 or 1754, Spallanzani received his doctorate in philosophy. After taking minor orders in the Roman Catholic church, he returned to the seminary to teach logic, metaphysics, and Greek in 1755. In 1757, he was ordained and, retaining his seminary post, became a lecturer in mathematics at the University of Reggio Emilia. The following year, he also began teaching Greek and French at Nuovo Collegio, which replaced the seminary. During these years, Spallanzani released his first publications, Theses philosophicae… (1757; philosophical theses) and Riflessioni intorno alla traduzione dell’ “Iliade” del Salvini… (1760; internal reflections on Salvini’s translation of the Iliad). By 1760, he had acquired a scholarly reputation and the epithet “the Abbé Spallanzani.” Paying minimal attention to his religious duties, he devoted his time, church income, and university salary to scientific research.

Physically, Spallanzani was of medium height and robust build. He had black eyes, an aquiline nose, a high forehead, a dark complexion, and a resonant voice. Athletic when young, he later enjoyed hunting, fishing, and playing chess. On the one hand, Spallanzani has been described as frugal, self-assured, sociable, and magnetic. On the other, this man of science has been called arrogant, intolerant, obstinate, and ambitious. Resenting criticism, he could be vengeful, ruthless, and violent when crossed.

Life’s Work

In 1761, Spallanzani began his biological research after reading works of Georges-Louis Leclerc, comte de Buffon, and John Turberville Needham. By 1762, he was a professor of mathematics at the university and of Greek at Nuovo Collegio. In 1763, Spallanzani became a professor of philosophy at the university and at the College of Nobles in Modena.

In Modena, Spallanzani attacked the theory of spontaneous generation, which asserted that living things could come into being without a living predecessor, an idea that was championed by Buffon and Needham. In his Saggio di osservazioni microsopiche concernenti il sistema della generazione de’ signori di Needham e Buffon (1765; account of microscopic observations concerning Needham and Buffon’s system of generation), Spallanzani reported hundreds of beautifully executed experiments on infusoria, which refuted Buffon and Needham’s views and confirmed that infusoria were living organisms that did not arise spontaneously in strongly heated infusions protected from contamination by air. Many considered Spallanzani’s experiments conclusive evidence against spontaneous generation.

Next, Spallanzani turned to regeneration and transplantation and then to circulation of the blood. His conclusions that “lower” animals have greater regenerative power than “higher” animals, that organisms generally regenerate only superficial organs, and that an individual organism’s ability to regenerate varies inversely with age were published in Prodromo di un opera da imprimersi sopra le riproduzioni animali… (1768; An Essay on Animal Reproductions, 1769). The first of Spallanzani’s works to appear in English, An Essay on Animal Reproductions received mixed reviews. In Dell’ azione del cuore ne’ vasi sanguigni (1768; on the action of the heart on the blood vessels), he described the effect of the systolic action of the heart upon blood flow in salamanders, extending and occasionally correcting Albrecht von Haller’s studies.

In 1769, Spallanzani moved to the University of Pavia, in Lombardy, where he spent his remaining years as a popular and famous professor of natural history. In addition, Spallanzani assumed direction of the university’s Natural History Cabinet (museum). There, he assailed spontaneous generation in his inaugural address, Prolusio (1770), then expanded his examination of circulation of the blood. This work culminated in De’ fenomeni della circolazione… (1773; Experiments upon the Circulation of the Blood… , 1801), which presented a physico-mechanical explanation of the heart’s action and the circulation of the blood and reported the first observation of blood passing through the capillaries of warm-blooded animals.

The results of Spallanzani’s continued investigation of infusoria appeared in Opuscoli di fisica animale e vegetabile… (1776; Tracts on Animals and Vegetables, 1784, 1786). Here, Spallanzani dispelled Needham’s objection that no infusoria grew in Spallanzani’s containers because heat had destroyed the vegetative force by showing that loosely corked infusions boiled longer and showed better growth than those boiled for shorter periods of time. He also refuted Buffon’s theory that spermatozoa developed in decomposing semen and demonstrated that they were components of living animals.

In the late 1770’s, Spallanzani’s popularity as a teacher swelled. He continued improving the museum, and he investigated animal digestion, biological reproduction, and artificial fecundation. In Dissertazioni di fisica animale e vegetabile (1780; Dissertations Relative to the Natural History of Animals and Vegetables, 1784, 1789), Spallanzani described his experiments on gastric digestion. Observing the solvent action of human and animal “gastric juices”—a term he coined for saliva, bile, stomach, and other secretions—he determined that digestion occurs primarily in the stomach and is a chemical, rather than mechanical, putrefying, or fermenting process. In addition, Spallanzani recounted experiments on animal sexual behavior, fertilization, and embryological development.

Seeking to discover how animal eggs are fertilized, Spallanzani examined the role played by semen in fecundation. He attempted artificial inseminations of several animals and was successful with a spaniel. His experiments demonstrated that contact between semen and egg is essential for fertilization, but he concluded that the solid parts of semen, not spermatozoa, were the fertilizing elements. In Dissertations Relative to the Natural History of Animals and Vegetables, Spallanzani argued for the embryological theory of preformation, contending that the preformed plant or embryo awaits fertilization within the egg and, after fertilization, expands according to a plan established by God. In his final section, he maintained that embryos exist in all plant seeds and develop with or without fertilization.

In this period, Spallanzani traveled in Europe, collecting museum specimens and indulging his passion for natural history. In 1784, he was offered a professorship at the prestigious University of Padua. Enticed to stay at Pavia by a year’s leave, a salary increase, and an ecclesiastical benefice, Spallanzani began his leave in August, 1785, by sailing to Istanbul, where he stayed for eleven months. His account of the journey describes the natural history and other aspects of Istanbul and Eastern Europe.

In 1788, Spallanzani visited the kingdom of the Two Sicilies, collecting for the museum and recording volcanic, geological, and other observations. While studying the active volcanoes Vesuvius, Stromboli, Vulcano, and Etna, he concluded that their eruptions resulted from gaseous explosions. Returning to Pavia, he performed chemical experiments on lava. These observations and investigations appeared as Viaggi alle due Sicilie e in alcune parti dell’ Appennino… (1792-1797; Travels in the Two Sicilies and Some Parts of the Apennines, 1798).

During the early 1790’s, Spallanzani conducted zoological research, most important on the flight of bats he had blinded, for example, by burning out their eyes. Led to reject the theory that flying bats avoid collisions by relying on touch, taste, smell, or hearing, his Lettere sopra il sospetto di un nuovo senso nei pipistrelli… (1794; Letters on a Supposed New Sense in Bats, 1941) suggested that a sixth sense or some unidentified organ in the head was responsible. Subsequently, however, Spallanzani accepted Louis Jurine’s theory, connecting bats’ flight with their hearing.

Then, Spallanzani’s research assumed a more chemical air. Johann Friedrich August Göttling’s erroneous description of the combustion of phosphorus prompted Spallanzani to examine that topic, and he published his results in Chimico esame degli esperimenti del Sig. Göttling, professor a Jena, sopra la luce del fostoro di Kunkel… (1796). Turning to respiration, he investigated gases emitted by plants enclosed in vessels of water or air, which were then placed in sunlight or shade. Part of a 1798 article, his last publication, stated his conclusions. Later, in Mémoires sur la respiration (1803; Memoirs on Respiration, 1804), some of Spallanzani’s papers on animal respiration were printed. In these papers, Spallanzani showed that oxidation occurs neither in the lungs nor in the blood, as had been argued, but in the tissues. Moreover, he demonstrated that during oxidation animal tissues emit carbon dioxide, which the blood then carries away—a discovery often attributed to nineteenth century chemistJustus von Liebig.

Throughout his life, Spallanzani enjoyed good health, although he experienced minor digestive disorders. In early February, 1799, complications from an enlarged prostate and chronic bladder infection sent him into a coma; he died a week later, one of the most famous contemporary scientists in the West.

Significance

Lazzaro Spallanzani possessed broad scientific interests and throughout his life published many reports and letters in scientific periodicals, in addition to his monographs. His treatises appeared in French, English, and German and were recognized for their literary style as well as their substance. Although Spallanzani’s conclusions often were debated by his peers and although some of his experiments are considered inhumane today, he remains known for an experimental skill that hardly was equaled for a century afterward. Most important, Spallanzani furthered the development of scientific thought in many fields.

Spallanzani’s experimentation on spontaneous generation added to evidence mounting against that theory. His experiments on infusoria contributed to the foundation of bacteriology, and his studies of their mortality when subjected to intense heat played a seminal role in the invention of food canning. Spallanzani’s experiments on animal sexual behavior, fecundation, semen, and spermatozoa led to the modern understanding of animal reproduction; his pioneering work on artificial fecundation and his successful artificial insemination of a viviparous animal—the first recorded—mark the beginning of modern work in that field.

Spallanzani achieved the first in vitro demonstration of animal digestion and established the basic theory of digestion held today. His ideas were not accepted immediately, but his work paved the way for nineteenth century biochemical studies of digestion. Spallanzani also laid the foundation for modern studies of animal and plant respiration. His research had little impact until the 1830’s, however, and was not continued until the late nineteenth century. Finally, among Spallanzani’s geological observations are notable contributions to mineralogy, and his work on volcanic eruptions is considered fundamental to modern volcanology.

Bibliography

Adams, A. Elizabeth. “Lazzaro Spallanzani (1729-1799).” Scientific Monthly 29 (1929): 529-537. Presents a reasonably accurate chronology of Spallanzani’s life and a well-documented assessment of his scientific method and contributions. Adams’s inclusion of translations from Spallanzani’s works and correspondence elevates this above other readily available biographical articles.

Bulloch, William. The History of Bacteriology. London: Oxford University Press, 1938. Chapter 4 includes a detailed account of the controversial theory of spontaneous generation, Spallanzani’s experimentation on infusoria, and his role in the theory’s demise.

Dinsmore, Charles E. “Lazzaro Spallanzani: Concepts of Generation and Regeneration.” In A History of Regeneration Research: Milestones in the Evolution of a Science, edited by Charles E. Dinsmore. New York: Cambridge University Press, 1991. This substantial essay on Spallanzani’s contributions to the study of animal regeneration is included in this chronicle of significant achievements in the study of reproduction.

Foster, Michael. Lectures on the History of Physiology During the Sixteenth, Seventeenth, and Eighteenth Centuries. Cambridge, England: Cambridge University Press, 1924. Lecture 8 describes Spallanzani’s experimental work on digestion and relates that work to that of his contemporaries.

Gasking, Elizabeth B. Investigations into Generation, 1651-1828. Baltimore: Johns Hopkins University Press, 1967. Chapter 11, devoted to Spallanzani, concentrates on his experiments and conclusions on animal sexual reproduction and fecundation, particularly the role of semen in fertilization, and places Spallanzani’s work within the context of the history of preformation.

Harris, Henry. Things Come to Life: Spontaneous Generation Revisited. New York: Oxford University Press, 2002. Chapter 4 in this examination of spontaneous generation includes information about Spallanzani’s experiments and theories.

Meyer, Arthur William. The Rise of Embryology. Stanford, Calif.: Stanford University Press, 1939. Offers illuminating accounts of Spallanzani’s investigation of spontaneous generation, animal reproduction, artificial insemination, hybridization, and his preformationist views. Meyer’s extensive excerpts from Spallanzani’s publications and correspondence are also enormously valuable.

Strick, James Edgar. Sparks of Life: Darwinism and the Victorian Debates Over Spontaneous Generation. Cambridge, Mass.: Harvard University Press, 2000. Although the book focuses on Darwin and his contemporaries, it includes a brief chapter, “Needham Versus Spallanzani,” contrasting the two scientists’ ideas about spontaneous generation.