Biography of Lazzaro Spallanzani
Lazzaro Spallanzani is one of the great names in experimental physiology and the natural sciences. Although not a physician, few physicians have delivered such important contributions to medicine. His investigations have exerted a lasting influence on the medical sciences. He made important contributions to the experimental study of bodily functions and animal reproduction. His investigations into the development of microscopic life in nutrient culture solutions paved the way for the research of Louis Pasteur.
A young man and his cousin
Spallanzani was born in Scandiano, a small town in the province of Emilia, northeast of the Apennines, to Gianniccolò, a distinguished lawyer, and Lucia Zigliani. At the age of fifteen years, after attending the local school, Lazzaro was sent to the Jesuit college at Reggio Emilio, seven miles away, where he received a sound education in the classics and philosophy. The Dominicans invited him to join the order, but he declined this offer and instead, in 1749, went to Bologna to study jurisprudence at the ancient university of that town. The professor of physics and mathematics at this university was the famous Laura Maria Caterina Bassi Veratti (1711-1778), a cousin on the paternal side. She was the first woman not only to have obtained a university degree, but also to have been given teaching posts in the university and in an academy, gaining an officially recognised role in the scientific community. Under her influence Lazzaro concentrated his efforts in mathematics and the natural sciences.
Besides acquiring a broad knowledge in the classics and of French, he worked for some three years towards his doctorate in law, a project that familiarised him with logic but otherwise grew distasteful. With Laura Bassi's support, Antonio Vallisnieri, professor of natural history at Padua and a fellow Scandianese, secured paternal consent for Lazzaro to abandon jurisprudence and follow his predilections.
Priest and teacher
Spallanzani became a doctor of philosophy in 1753, and in 1757 he was ordained a priest. After that he was commonly designated "l'Abate Spallanzani". His priestly offices were performed irregularly; nevertheless, even in later life he still ordained at mass. Since he had no private income, the financial assistance (and moral protection) of the church facilitated his investigations of natural phenomena.
Early in 1755 Spallanzani began teaching logic, metaphysics, and Greek language at the ancient College of Reggio, Lombardy. In 1757 he was appointed lecturer in applied mathematics at the small, recently founded University of Reggio Emilia. The next year he was concurrently professor of both Greek and French at Nuovo Collegio, which, presumably, replaced the old seminary.
A man of classical education, Spallanzani in 1760 published an article critical of a new translation of the Iliad. All his leisure time, however, was devoted to scientific research.
Into the mountains
In the summer of 1761 Spallanzani, an indefatigable walker and daring climber, set out for the Reggian Apennines and Lake Ventasso, on the first of many scientific excursions to various parts of Italy and elsewhere. his main concern on this journey was the origin of springs and fountains gushing from the mountain slopes. In 1715 Antonio Vallisnieri the elder (1661-1730), had stated that water precipitated near the summit, whether as snow, rain, or mist, insinuated itself between sloping strata of the mountain and descended by gravity until arrested by an impervious stratum. Spallanzani verified this concept by observing such factors as the relationship between the number and size of springs and total precipitation in the area, the water-condensing characteristics of the mountains involved; and the disposition, nature and water affinity of the constituent strata,
In 1761 Spallanzani was introduced by Vallisnieri to works of Georges Comte de Buffon (1707-1788) and to those of his occasional collaborator, the English priest and microscopist John Tuberville Needham (1713-1781). His first biological work, published in 1765, was an attack on the biological theory suggested by Buffon and Needham, who believed that all living things contain, in addition to inanimate matter, special "vital atoms" that are responsible for all physiological activities. They postulated that, after death, the "vital atoms" escape into the soil and are again taken up by plants. The two men claimed that the small moving objects seen in pond water and in infusions of plant and animal matter are not living organisms but merely "vital atoms" escaping from the organic material. Refuting this theory was later to become one of Spallanzani's greatest contributions.
In 1768 he published the results of his regeneration and transplantation experiments. One hundred years earlier, in one of the first examples of a biological experiment with proper controls, the Italian physician and philosopher/poet, Francesco Redi (1626-1697) had set up a series of flasks containing different meats, half of the flasks sealed, half open. He then repeated the experiment but, instead of sealing the flaks, covered half of them with gauze so that air could enter. Although the meat in all the flasks putrefied, he found that only in the open and uncovered flasks, which flies had entered freely, did the meat contain maggots. Redi thus had dispelled the myth of spontaneous regeneration for complex animals.
Spallanzani's studies of regeneration included planarians, snails, and amphibians and reached a number of general conclusions: the lower animals have greater regenerative power than the higher; young individuals have a greater capacity for regeneration than the adults of the same species; and, except in the simplest animals, it is the superficial parts not the internal organs that can regenerate. His transplantation experiments showed great experimental skill and included the successful transplant of the head of one snail onto the body of another.
In 1763 Spallanzani went to Modena as professor of philosophy at the university and at the College of Nobles. In Modena he taught natural history until 1769, and later taught the same discipline in Pavia. In 1766 he published a monograph on the mechanics of stones that bounce when thrown obliquely across water.
Spallanzani found his daily lectures taxing, and other duties interrupted his researches. He took charge of the public Museum of Natural History of the university, the development of which the court at Vienna supported through its minister plenipotentiary, the governor of Lombardy, Count Carlo di Firmian (1718-1782). The acquisition of exhibits proved congenial to Spallanzani's aggressive instincts and broad vision, so that within a decade the collections of the museum were among the most magnificent in Italy. In the summer of 1772, when the government sent him to visit the mines and collect fossils in the Alps north of Milan, his itinerary included lakes Como and Maggiore, and the towns and villages of Ticino.
In 1773 Spallanzani investigated the circulation of the blood through the lungs and other organs and did an important series of experiments on digestion, in which he obtained evidence that digestive juice contains special chemicals that are suited to particular foods.
In his investigations he used gastric juice from many different animals and often experimented upon himself. He obtained specimens from the living by means of a sponge attached to a cord. In his attempts to induce digestion artificially, he used his own gastric juice which he made available by vomiting. He verified René Antoine Ferchauld de Reaumur’s (1683-1757) conclusions concerning the digestive powers of gastric juice, proving in addition that it prevented putrefaction. Spallanzani observed that gastric digestion was neither putrefaction nor fermentation and erroneously concluded that it was not acid.
In his work De’ fenomeni della circolazione osservata nel giro universale de’ vasi, Spallanzani presented the results of his experiments on the circulation of the blood and the action of the heart. He showed that the impetus given the blood by the contraction of the heart was maintained throughout the entire arterial system down to the smallest capillary. As was true with most of his works, this one was translated into a number of other languages.
On her majesty's service
Spallanzani's scientific accomplishments and growing renown as an eloquent, informative lecturer brought offers of chairs at Parma and Pavia. The latter city had been in Austrian hands for more than fifty years. The government of Maria Theresa (1717-1780), archduchess of Austria, Holy Roman Empress, queen of Hungary and Bohemia, and the only woman ruler in the 650 year history of the Habsburg dynasty, sought to restore some of its ancient dignity by appointing new professors to a reconstituted university. The prospects of higher emoluments and greater distinction proved irresistible, and Spallanzani became professor of natural history at Pavia in November 1769.
Spallanzani excelled in the role of teacher. He was elected rector for the scholastic 1777-1778. Enrolment in his natural history course had increased each year and in 1780 exceeded 115. Finally, as thee were large gaps in the museum collections and he was starved for travel, his curiosity and talents could be exercised on specimen gathering excursions. His appetite was whetted in 1779, when, after several annual postponements, he enjoyed a month-long summer tour of Switzerland. During this time he stayed for several days at Bonnet's outside Geneva. There he met the Swiss botanist Jean Senebier (1742-1809) and other naturalists, Abraham Trembley and his nephew, and Genevois H. B. de Saussure (1740-1799) all of whom he deeply impressed. In 1787, with Saussure made the second ascent of Mount Blanc (4,807), Europe's highest mountain. Jean Senebier in 1799 discovered that CO2 is required for photosynthetic growth.
On the return journey he called on Albrecht von Haller's (1708-1777) widow and son at Bern and visited other Swiss cities. In his letter og thanks to Bonnet, Spallanzani stated that of all the natural history museums he visited in Switzerland, only Zurich possessed one where the collections and curator were not amateurish.
During the next five years, Spallanzani made several marine and overland excursions, mostly during summer vacations. In 1781 he went to the Mediterranean coast near Marseille, 1782-1783 to Istria and the Adriatic coast. His longest voyage took place in 1785, when he sailed on a gunboat with a flotilla escort, as a guest to Zulian, the Venetian envoy to the Porte. Two months later they reached Constantinople, where Spallanzani was given quarters in Zulian's palace. Their ship had nearly foundered in a gale off Kithira, where they refitted; then, having threaded the Cyclades, they reached Tenedos, whence the sultan's emissaries escorted them to the locality that excavators a century later identified as the site of Homer's Troy. Spallanzani never forgot that he was a natural historian, even while exploring territory suffused with classical and Homeric reminders.
In August 1786, having dispatched the valuable museum collections by ship, Spallanzani set out with a single attendant on the unimaginably difficult return overland. Despite hazardous mountain passes, floods and torrents, brigands and cut-throats, detours were made to inspect mines and geological structures, and more specimens were collected. He reached Bucharest through the eastern Balkans, crossing the Transylvanian Alps to the Hungarian plain and also Buda and Pest. In December he was welcomed in high circles in Vienna and bemedaled by Joseph II (1741-1790), Maria Theresia's son and previous co-regent, now Roman Emperor.
In 1788 Spallanzani journeyed to the Two Sicilies, mainly in order to correct deficiencies in the volcanic collections of the museum. Southern Italy had suffered for five years from intense eruptive and seismic activities. Messina was still in ruins and the countryside devastated. Vesuvius, near Naples, Stromboli and Vulcano on the Eolian Isles, and Etna on the Island of Sicily, remained active. Spallanzani visited them all, undauntedly making several perilous ascents that involved great physical endurance.
On the nature of life
In his two-volume work, Opuscoli di fiscia, e vegetabile, published in 1776, Spallanzani rejected the then-popular theory of spontaneous generation. The work also contains two letters written to Spallanzani by the Swiss naturalist Charles Bonnet (1720-1793), a well-known supporter of the theory of preformation.
Most of the experiments described in the Opuscoli consist of observations Spallanzani made on infusions of vegetable matter heated in closed vessels for various periods of time and set aside to await developments that would later be viewed with the eye or under the microscope. Spallanzani confirmed the view of Antonie van Leeuwenhoek (1632-1723) that such forms are living organisms. In a series of experiments he showed that gravy, when boiled, did not produce these forms if placed in phials that were immediately sealed by fusing the glass. As a result of this work, he concluded that the objects in pond water and other preparations were living organisms introduced from the air and that Buffon's views were without foundation.
In his experiments, Spallanzani boiled various kinds of seeds in a flask and stoppered it. After a few days, many organisms could be found in the flask; Spallanzani distinguished the larger ones, which were destroyed by boiling for one-half minute, and microbes, which survived boiling and developed even after the flask had been sealed. Eventually, he discovered that, after boiling sealed flasks for as
long as 45 minutes, no microorganisms developed. Although the matter of spontaneous generation was not resolved by this book, it clearly foreshadowed subsequent experiments by other investigators which culminated nearly a century later in Pasteur’s epic work. The compilation contains six folding plates which depict over forty of Spallanzani’s microscopic observations.
Generations to come
At the request of his friend Charles Bonnet, Spallanzani investigated the male contribution to generation. Although the spermatozoa had first been seen by Leeuwenhoek, their function was not understood until some 30 years after the formulation of the cell theory in 1839. As a result of his earlier investigations into simple animals, Spallanzani supported the prevailing view that the spermatozoa were parasites within the semen.
Both Bonnet and Spallanzani accepted the preformation theory. According to their version of this theory, the germs of all living things were created by God in the beginning and were encapsulated within the first female of each species. Thus, the new individual present in each egg was not formed de novo but developed as the result of an expansion of parts the delineation of which had been laid down within the germ by God at the creation. It was assumed that the semen provided a stimulus for this expansion, but it was not known if contact was essential nor if all the parts of the semen were required.
Using amphibians, Spallanzani showed that actual contact between egg and semen is essential for the development of a new animal and that filtered semen becomes less and less effective as filtration becomes more and more complete. He noted that the residue on the filter paper retained all its original power if it were immediately added to the water containing the eggs. Spallanzani concluded that it was the solid parts of the secretion, proteinaceous and fatty substances that form the bulk of the semen, that were essential, and he continued to regard the spermatozoa as inessential parasites. Despite this error, Spallanzani performed some of the first successful artificial insemination experiments on lower animals and on a dog.
One of the partisans of Spallanzani's views against the hypothesis of spontaneous generation was Voltaire ( François-Marie Arouet, 1694-1778).
Spallanzani remained an active explorer of nature well into high age. His last personal report, appearing in 1798, contained the novel observation that whereas plant kept in water and in sunlight furnish oxygen and absorb carbon dioxide, they reserve this exchange in deep shade.
Spallanzani died peacefully of uraemic coma at the night of February 11, 1799.
- If I set out to prove something, I am no real scientist – I have to learn to follow where the facts lead me – I have to learn to whip my prejudices.