Dedication by Louis Pasteur: "Portrait of my fellow philosopher Ch. (Charles) Chappuis. Produced in Besançon in 1845." Between the ages of 13 and 20, Louis Pasteur completed about 40 pastels and drawings, constituting quite an anthology of portraits of 19th century men and women. By embarking on his career as a scientist, Louis Pasteur abandoned his pastels for the marvels of the microscope.