American medical researcher and virologist (1914-1995) known for developing the polio vaccine. Three items: a TLS, one page, 8.5 x 11, August 21, 1969, The Salk Institute for Biological Studies, in full: "Letters have to be very brief because time is at a premium. But I do want to thank you for your nice thoughts"; and a pair of FDCs with cachets honoring American Blood Donors, both postmarked on March 12, 1971, both signed in black ink by Jonas Salk. In overall fine condition.
