French physician; born in 1831. He studied in Paris at the Lycée Henri IV., and in 1851 entered the Institut Agronomique at Versailles. In the following year this institution was suppressed on suspicion of republicanism, and Leven, while lecturing on science at the Lycée Bonaparte, began his medical studies (M.D. 1860; his thesis, "Rapports de l'Idiotie et du Crétinisme," gained a gold medal from the Sociét´ Médicopsychologique of Paris). In 1863 he was appointed physician to the Compagnie du Chemin de Fer du Nord, and in 1870-71 was ambulance-surgeon of the ninth arrondissement of Paris and of the Bataillon du Chemin de Fer du Nord, receiving the military ribbon of the Legion of Honor in 1871. From 1871 to 1878 he was a member of the Board of Health of Paris, and from 1873 to 1889 head physician of the Hôpital Rothschild. Leven is especially noteworthy for his work in gastric pathology. He is the author of "Traité des Maladies de l' Estomac," 1879; "L'Hygiène des Israélites," 1883; "Estomac et Cerveau," 1884; "La Névrose," 1887; "Système Nerveux et Maladies," 1893; and "La Vie, l' Ame, et la Maladie," 1902.
Leven is known also as a philanthropist. Together with Eugène Manuel he founded, in 1848, the first night-school for Jewish apprentices, which developed into a manual-training school; and he has been the president of its administrative council since 1879. He is also one of the founders of the Alliance Israélite Universelle, vice-president of the Comité des Ecoles Israélites, member of the Comité de Refuge du Plessis-Piquet (an agricultural school), and chevalier of the Order of Isabella the Catholic.