Louis Pasteur, the French chemist renowned for discovering the process of pasteurization, had one brother and three sisters, according to NNDB. His brother did not live to adulthood.
According to NNDB, Louis Pasteur's brother, Jean Denis, was born in 1816 and passed away in 1817. His older sister, Jeanne Antoine, was born in 1818 and died in 1880. His two younger sisters were Joséphine, who was born in 1825 and died in 1850, and Jeanne Emilie, who was born in 1826 and died in 1853.
Louis Pasteur was the middle child, having been born in 1822. He also outlived all his siblings, passing away in 1895.