(b. Laeken, Belgium, 4 September 1858; d. Uccle, Belgium, 1 August 1905)
botany, biology, philosophy.
The son of a distinguished Venetian banker, Giacomo Errera, and of Marie Oppenheim, who was of German origin, Errera must have spent his early years in an exceptional environment. His father, who was the Italian consul general in Belgium, was an ardent patriot who had fiercely defended Venice against the Austrians in 1849. His maternal grandfather was a revolutionary who fought for new political ideas in 1830 in Frankfurt. Errera was a brilliant student at the Faculty of Letters of the University of Brussels, where he received his baccalaureate. He continued his studies at the Faculty of Sciences of the same university, and was awarded the doctorate in 1879. After spending some time abroad, in 1884 Errera was named university lecturer in anatomy and plant physiology at the University of Brussels. In 1885, he married his first cousin, Rose-Eugenie May. He was elected in 1887 to the Royal Academy of Sciences, Letters, and Fine Arts of Belgium.
In 1894 he succeeded J. E. Bommer in the chair of general botany, a position that he held until his death in 1905 and that he enhanced by such achievements as the creation of the first botany laboratories for students. Among his many students those who were to become outstanding in Belgian biological science were Émile Laurent, Jean Massart, Émile Marchal, and Émile de Wildeman. Errera was, first and foremost, a remarkable teacher and was responsible for countless academic and pedagogical reforms. The first to publish (in 1897) wall charts for the teaching of plant physiology, Errera throughout his life displayed an interest in pedagogy, and his lecture entitled “The Utility of Superfluous Studies” shows clearly the direction of his didactic ideas.
In spite of his early death, Errera left a body of astonishingly varied scientific work. Although not a taxonomist, he undertook, while still very young, studies on the genus Epilobium and the phylogeny of the Salix. This work led to the publication of a paper entitled “Routines et progrés de la botanique systématique,” in which he defined with clarity and foresight what was to become the taxonomy of today. In ethology Errera appears as a precursor because of his research work on the heterostylism of the Primula—revived by Jules MacLeod—on the fertilization of Pentastemon and Geranium. But it is in the domain of plant physiology that Errera’s contribution is most striking. He first studied the alkaloids, precisely describing their microchemical characteristics and their localization. He was the first to point out the presence of glycogen, forming protoplasm, in the Ascomycetes. Subsequently he discovered this polysaccharide—which had previously been thought to exist only in animals—in a series of microorganisms. Again, in physiology, Errera was a pioneer in the area of physicochemical analysis. In fact, he was the first, making use of the remarkable work of Henri Devaux, to explain the arrangement of cellular walls by utilizing surface tension. Errera again touched upon biophysics when he investigated the mechanisms of the rising of sap and of the growth of the sporangiferous filaments of the Phycomycetes. Errera also took up the study of the transmission of acquired characteristics by the Aspergillus in its adaptation to concentrated solutions. Errera seems to have been one of the first biologists to undertake the study of life from a strictly physicochemical perspective, and the title of one of his posthumous works, Cours de physiologie moléculaire, is a good illustration.
Errera was a controversialist of the first order and became internationally known for his condemnation of anti-Semitism and for two courageous articles, “L’acte de tolerance” and “Six sermons sur les juifs.” A warmhearted man and a poet in his leisure time (he left several collections of verse), Errera may be considered one of the most authentic humanists of the late nineteenth century.
I.Original Works. The edition Recueil des oeuvres de Léo Errera includes Botanique générale I (Brussels, 1908); Mélanges, vers et prose (Brussels, 1908); Botanique géenérate II (Brussels, 1909); Physiologie générale, Philosophie (Brussels, 1910); and Pédagogie, Biographies (Brussels, 1922).
II. Secondary Literature. On Errera and his work see L. Frédericq and J. Massart, “Notice sur L. Errera,” in Annuaire. Académie royale de Belgique (1908), 131–279; J. Massart, Léo Errera, Hayez, ed. (Brussels, 1905); and University of Brussels, Gutenberg, ed., Commémoration Léo Errera (Brussels, 1960).
P. E. Pilet