Autograph note signed, one page, 4 x 3,5 inch, `The Rockefeller Institute` stationery, (New York), 13.05.1966, to an unnamed correspondent - concerning an autograph request, written and signed in dark ink "Your request has given pleasure to Peyton Rous - May 13, 1966", attractively mounted (removable) for fine display with a photograph, shows Francis Peyton Rous as virologist (altogether 8,25 x 11,75 inch), in very fine condition.