MIRBEL, CHARLES FRANçOIS BRISSEAU DE

(b. Paris, France, 27 March 1776; d. Paris, 12 September 1854)

botany.

The son of a jurist, Mirbel began his studies in Paris at a private boarding school run by the Congregation of the Picpus; the Revolution forced him to interrupt his education and to seek refuge with his parents at Versailles. When he was conscripted during the Terror, he hid in Toulouse, waiting for conditions to become more settled. Through the aid of a friend Mirbel returned to Paris, where, in the office of Lazare Carnot, then member of the Committee of Public Safety, he did work in topography and military history.

In 1796, through his position as secretary to General Henri Clarke, Mirbel learned of a proscription list that included the name of a friend’s relative. He warned the man immediately so that he could escape. Clarke ordered Mirbel’s arrest, but he fled to the Pyrenees, profiting from his enforced exile by studying physics, mineralogy, and botany. His first research, carried out in collaboration with Louis Ramond de Carbonniéres, professor of natural history at the École Centrale of Tarbes, dealt with the geological configuration of the Pyrenees.

In 1798, after two years of exile—and in order to escape military conscription to serve in the Egyptian campaign—Mirbel returned to Paris and obtained a post in the Museum of Natural History.

The following year Mirbel presented a memoir on ferns to the Academy of Sciences, and in 1801 and 1802 he submitted a series of articles on the structure of plants and on the seed and embryo. Thus he inaugurated the study of microscopical plant anatomy in France. He showed that the characteristics of the seed and of the embryo are identical for all plants of the same natural family, thereby laying the foundations of embryogenic classifications, which are still used.

In 1802 Mirbel married a young woman who was related through her mother to the Dandolo family of Venice. His wife’s influence helped him to obtain the post of head gardener at Malmaison, the country palace of Napoleon and Josephine. On 9 May 1806 Mirbel presented to the Academy remarks on a system of comparative plant anatomy based on the organization of the flower and a memoir on plant fluids. At the end of 1806, seeking the financial security he had always lacked, Mirbel entered the service of Louis Bonaparte, king of Holland. On 17 March 1807 he was named a correspondent of the Academy of Sciences.

Mirbel’s new duties afforded him sufficient time to pursue his research on plant organography and physiology. He was elected a member of the botany section of the Academy of Sciences on 31 October 1808. He was appointed supplementary professor of botany at the Faculty of Sciences in Paris, then the center of a renaissance in scientific education; Desfoniaines, Gay-Lussac, and Poisson were teaching there. Mirbel’s work benefited greatly from his association with the Faculty. Between 1809 and 1815, in a series of notes and memoirs and in his lectures, he challenged orthodox opinion by asserting the independence of plant cells in the different tissues. His Éléments de botanique (1815), which revealed his talents as a draftsman, contributed to the acceptance of his ideas.

In 1816, after Napoleon’s abdication, Mirbel accepted the posts of secretary-general of the Ministry of the Interior and maitre des requêties of the Council of State, using his positions to obtain passage of measures that would advance science. He resigned on 20 February 1820 when, following a cabinet reorganization, his friend Élie Decazes, who had helped him to secure those posts, was named ambassador to England. Mirbel joined Decazes in England, where he met several English scientists.

On his return to France, Mirbel, whose wife had died, married Lezinka Rue, curator of Louis XVII’s art collection. He was appointed professor-administrator of the Jardin des Plantes in 1829, replacing Bosc, who had died. Mirbel’s research activity was at its height from 1825 to 1846. Using the microscope he followed the first stages of the formation of the tissues and studied the origin, development, and organization of the phloem and wood. In his papers on the development of the ovule, on the structure of Marchantia, on the formation of the embryo, on the disposition of the tissues in the stems and roots of the monocotyledons, and on the cambium the rigor of the draftmanship strengthened the presentation of the material.

Between 1843 and 1845 Mirbel demonstrated that the cambium contains ternary substances and various nitrogenous materials, which include the most active parts of the plant, those that secrete cellulose and produce all the organic and mineral substances. In this pioneering work, therefore, living protoplasm was differentiated from the cell wall. The formation of the cuticle and the lignification of the vessels were described by means of simple chemical reactions in which Mirbel anticipated plant cytochemistry. Through the study of vascularization in date trees and other monocotyledons, he demonstrated that the plant is formed of two parts that begin at the collar: one descends into the soil, and the other rises above the substratum.

Mirbel was continuing his investigations when his second wife died of cholera in 1849. Exhausted and bereaved, Mirbel gradually lost his memory. He spent his last years in peaceful retirement, cared for by his daughter. He died in 1854, at the age of seventy-eight.

BIBLIOGRAPHY

I. Original Works. A list of 67 papers written or coauthored by Mirbel is in Royal Society Catalogue of Scientific Papers, IV, 405–407. His principal works include Traité d’ anatomie et de physiologie végétales, 2 vols. (Paris, 1802); Histoire naturelle générale et particulière des plantes, 18 vols. (Paris, 1802–1806), to which he contributed; Éléments de physiologie végétale, et de botanique, 3 vols. (Paris, 1815); and Physique végétale, ou Traité élémentaire de botanique (Paris, 1832).

II. Secondary Literature. See Élie Margollé, Vie et travaux de M. de Mirbel d’après sa correspondance et des documents inédits (St. Germain, 1863); and M. Payen’s biography of Mirbel, in Michaud, Biographie universelle, new ed., XXVIII, 382–387; based largely on his Éloge historique de M. de Mirbel (Paris, 1858).

A. NougarÉde