Signed First Day Cover.
This French-American microbiologist and environmentalist developed the first commercially produced antibiotics; his 1969 "So Human an Animal" was awarded a Pulitzer Price. Signed First Day Cover, 6½" X 3½", cancelled in Spokane, Washington on 18 April 1974 and with "First Day of Issue" boldly stamped. Single 10-cent "Expo'74" stamp at..... More