The History of Polio - Image Gallery / RogersPBFDR-1916travel-p37 -
RogersPBFDR-1916travel-p37.jpg
US Public Health Service travel certificate certifying child free of polio, 1916
(Naomi Rogers, Dirt and Disease: Polio Before FDR (New Brunswick, NJ: Rutgers University Press, 1990), p. 37)