Lieberkühn, Johannes Nathanael

(b.Berlin, Germany, 5 September 1711; d. Berlin, 7 December 1756)

anatomy.

One of the most skillful German anatomists of the early eighteenth century, Lieberkühn was the son of Johannes Christianus Lieberkühn, a goldsmith. His father insisted that Johannes and his brother plan for careers in theology; thus prior to attending the academy at Jena, the boy was sent to the Halle Magdeburg Gymnasium.

At Jena, Lieberkühn studied mathematics, mechanics, and natural philosophy, coming under the influence of the physician-iatromathematician G. E. Hamberger (1697–1755), His interest in medicine was sharpened by this experience and lie went on to study chemistry, anatomy, and physiology with Hermann Friedrich Teichmeyer (1685–1744) and Johann Adolph Wedel (1675–1747). Lieberkühn left Jena in 1733 and joined his brother at Rostock as a candidate to become a preacher. Here he delivered only a few sermons, choosing instead to continue studies of what most interested him. Johann Gustav Reinbech (1683–1741), the noted Protestant theologian, recognized Lieberkühn’s aptitude for scientific studies and introduced him to the Prussian king, Frederick William I. After interviewing Lieberkühn, the king released him from the career set by his father, who had died in the meantime, so that he could devote full time to science and medicine.

Evert before Lieberkühn returned to Jena in 1735, the Berlin Academy of Sciences enrolled him as a fellow as a result of his earlier work at Jena. Subsequent to his second period at Jena, Lieberkühn traveled and studied in other centers, including the Imperial Natural Sciences Academy in Erfurt, where its president, A. E. Buchner, made him a fellow,

He pursued further medical study, especially of anatomy and chemistry, at Leiden under Boerhaave, B. S. Albinus, J. D. Gaub, and Swieten. Lieberkuhn’s Leiden tutelage culminated in the award of a medical degree in 1739. His dissertation, De valvula coli et usu processus vermicularis, was commended by Boerhaave and Swieten. Another dissertation written at this time, “De plumbi indole,” was not published and apparently is no longer extant.

Lieberkühn’s fascination with anatomical structures and their mechanisms expressed itself in his De fabrica et actione villorum intestinorum tenuium hominis (1745). Here, for the first time, were described, in greatest detail, the structure and function of the numerous glands attached to the villi, appropriately called Lieberkühnian glands, as well as the structure and function of the villi found in the intestines.

All of these were made comprehensible by the meticulous and skillful injections of a mixture of wax, turpentine, and colophony or dark resin.

To explain the flow of fluids into these intestinal components Lieberkühn constructed a model. By means of an open curved brass tube, cone-shaped at both ends, with two outlet tubes placed toward the narrow center, each of which drained into a separate vessel, he demonstrated the flow of chyle from the arterioles to the villi and the ascent of the lymph from the villi into the small veins. He used tinted water to show the flow of lymph from the villus into the veins and plain water to emulate the flow of chyle to the villus. As a result of his excellent demonstrations of the intestinal contents of an experimental animal before the members of the Royal Society of London, Lieberkühn was made a fellow in 1740.

In the tradition of Hamberger, his first medical teacher at Jena, Lieberkühn explored the circulatory vessels, devising special microscopes to view in greater detail the intricacies of fluid motion within the living animal. One of these was the anatomical microscope used for viewing the circulation in frogs. The specimen was attached to the body of the microscope, which consisted of two thin silver plates between which was placed a small lens and around which were arranged hooks to hold and manipulate the animal. The part of the animal to be observed was fixed over the lens.

En route to Leiden, Lieberkühn had visited Amsterdam, where he saw a solar microscope similar to the one Fahrenheit made in 1736. Another microscope, for the invention of which Lieberkühn has been given credit, to be used in illuminating opaque objects, was based on the principle of Fahrenheit’s solar microscope. It consisted of a small, concave, highly polished silver speculum, later termed a Lieberkühn, that provided intense reflection of the sun’s rays directly upon the object. Although Descartes had shown a solar microscope in his Dioptrique as early as 1637, it was probably due to Lieberkühn’s revival of interest in it that the speculum arrangement on this microscope received his name. Lieberkühn’s solar microscope is illustrated in William Carpenter’s The Microscope and Its Revelations (7th ed. [Philadelphia, 1891], p. 138). The noted English microscope maker John Cuff (ca. 1708–1772) later adapted Lieberkühn’s model by adding a mirror to it which provided better control by reflecting the sun’s rays to the speculum and then to the object.

After settling in Berlin in 1740, Lieberkühn practiced medicine until his death at the age of 45. His most significant contribution during these last sixteen years of his life grew out of his desire to expose and preserve the vascular tissues of various animals. He assembled a collection of over 400 items which consisted of three main types of anatomical preparations: those preserved in a transparent liquid; dry specimens injected and hardened; and injected preparations of minute pieces of tissue (especially lung) to be viewed under the microscope. After his death this collection was advertised by a Paris dealer named Mettra and eventually was broken up and sold to several museums, as were other instruments he had constructed, including pneumatic pumps, pyrometers, and air guns.

Lieberkühn was survived by his wife, the former Catherine Dorothy Neveling, and a son and a daughter,

Lieberkühn combined a gift for observation with technical facility, enabling him to perfect the instruments and injections required to explore the most minute vascular structure of both living and preserved organisms.

BIBLIOGRAPHY

I. Original Works. A collected ed. of Lieberkühn’s works appeared under the title Dissertationes quatuor, omnia nunc primum in utuun collecta…, John Sheldon, ed. (London, 1782). This ed. contains Memoria extracted from the Berlin Academy Memoirs (1758), “Sur les moyens propres à découvrir la construction des viscères,” which appeared originally in the Memoirs of 1748, and “’Description d’un microscope anatomique,” which appeared originally in the Memoirs of 1745. Other writings are Defabrica et actione villorum intestinorum tenuium hominis (Leiden, 1739); and De valvula coli et usu processus vermicularis, his dissertation for the medical degree (Leiden, 1745).

II. Secondary Literature. The best sources for an account of Lieberkühn’s life are the Memoria published in the Sheldon ed, and the ėloge by Formey published in the Berlin Academy Memoirs in 1756. The most explicit description of his anatomical preparations appears in L’annėe littėraire (1764), 136–140.

Audrey B. Davis