STENO, NICOLAUS (Niels Stensen; 1638–1686)

STENO, NICOLAUS (Niels Stensen; 1638–1686), Danish anatomist, paleontologist, and geologist. Born 11 January 1638 to a Copenhagen goldsmith, Steno attended the University of Copenhagen from 1656 to 1660, where he studied medicine and anatomy with Thomas and Erasmus Bartholin. Moving on to Amsterdam and Leiden from 1660 to 1664, he made several important discoveries concerning glands, which were a new field of investigation. Inspired by René Descartes's Treatise on Man (published posthumously in Leiden in 1662), Steno began studying the physiology of the heart, and he came to argue, against both Descartes and William Harvey, that the heart was not a specially endowed organ but merely a muscle. Failing to secure a position at the University of Copenhagen, Steno traveled to Paris, came under the patronage of Melchisedec Thevenot, and continued his anatomical studies. He gave a lecture on the brain in 1665 in which he took further issue with Descartes's theories of brain function, and he argued that ideas about brain physiology should be grounded in the results of detailed dissection. This lecture was published four years later as Discourse on the Anatomy of the Brain and was the most influential of his anatomical works.

Continuing his slow journey south, Steno spent some time in Montpelier in 1665, and in 1666 he arrived at Pisa and the summer court of the Medici family of Florence. He was invited to join the circle of the Accademia del Cimento, and he readied for publication a study of muscle anatomy. His career abruptly changed course when he was given the head of a giant white shark to dissect by the grand duke, Ferdinand II. Steno was indeed interested in the muscle anatomy of the shark, but he was even more fascinated by its teeth, which closely resembled the fossil objects known as glossopetra or tonguestones. Tonguestones, and nearly all other fossils, were commonly regarded as mineral objects that grew in the rocks where they were found and were not thought to have an organic origin. Steno considered the problem and offered compelling reasons why tonguestones must have once been sharks' teeth. When he published his Elements of Myology in 1667, he appended to it a short treatise, "The Dissection of the Head of a Shark." This essay marks the beginning of the science of paleontology.

Steno then addressed the more general problem of ascertaining the history of rock formations by examining the clues within them. He formulated principles by which he could determine if formations had been moved or altered after they had been laid down and which formations had been deposited first. Within eighteen months, he had completed his major geological treatise, Prodromus to a Dissertation on Solids Naturally Contained Within Solids. Steno argued here that rock strata are like the pages in a book of history, and that proper understanding of the principles of stratigraphy will allow that book to be read. The Prodromus marks the beginning of historical geology.

Steno resumed his travels in 1668, touring much of central Europe; he returned to Florence in 1670 for two years and then was invited back to Copenhagen in 1672, where he was royal anatomist until 1674. But his interest in anatomy had been waning for some time. Steno had converted to Catholicism in 1667, and he gradually turned his attention to religious and churchly matters. He returned to Florence in 1675 to be ordained a priest; in 1677 he was appointed apostolic vicar of the northern missions (Germany), and shortly thereafter became the titular bishop of Titiopolis. He spent the last nine years of his life in Hanover, Münster, and Hamburg, trying to bring the followers of Luther back into the Catholic Church. He died on 5 December 1686 in Schwerin. The grand duke of Florence, Cosimo III de' Medici, had Steno's body brought back to Florence, where he was buried in the cathedral of San Lorenzo. About three hundred years later, on 23 October 1988, Steno was beatified by Pope John Paul II.

See also Anatomy and Physiology ; Descartes, René ; Florence ; Geology ; Harvey, William ; Scientific Revolution .

BIBLIOGRAPHY

Primary Sources

Steno, Nicolaus. Discours sur l'anatomie du cerveau. Paris, 1669.

——. Elementorum Myologiae Specimen . . . cui Accedunt Canis Carchariae Dissectum Caput. Florence, 1667.

——. De Musculis & Glandulis Observationum Specimen. Paris, 1664.

——. De Solido Intra Solidum Naturaliter Contento Dissertationis Prodromus. Florence, 1669.

——. Steno: Geological Papers. Edited by Gustav Scherz. Translated by Alex J. Pollock. Odense, 1969.

Secondary Sources

Kardel, Troels. Steno: Life, Science, Philosophy. Copenhagen, 1994.

Scherz, Gustav, ed. Dissertations on Steno as Geologist. Odense, 1971.

——. Nicolaus Steno and His Indice. Copenhagen, 1958.

William B. Ashworth, Jr.