French scientist and bacteriologist whose studies on fermentation led to the conclusion that it was caused by bacteria, proving the germ theory of disease; he also developed a successful vaccine for rabies, which hitherto had been universally fatal. ALS in French, signed “L. Pasteur,” one page, 5.25 x 8, July 14, 1876. Letter to a friend. In part, “These few words you allow me to address to you will be passed on to you by Mr. Ferdinand Boutroux, the young man I told you about who is suffering from intermittent fevers.” Beneath Pasteur’s letter is a note from Pasteur’s son indicating the man mentioned is the doctor’s son-in-law. In fine condition, with expected folds and some mild toning. COA John Reznikoff/PSA/DNA and R&R COA.
