Complex sentence: He studied botany under Bernard de Jussieu (1699--1777), and in 1793 attained the chair of horticulture at the "Muséum national d'histoire naturelle" in Paris.
Split into simpler sentences: He studied botany under Bernard de Jussieu (1699--1777). In 1793 Thouin attained the chair of horticulture at Muséum national d'histoire naturelle in Paris.