This photograph was recently requested for a scholarly book and is new to this website. Alfred Blalock was an American surgeon most noted for his work on the medical condition of shock as well as Tetralogy of Fallot, commonly known as Blue baby syndrome.
Along with his research and laboratory assistant Vivien Thomas, and pediatric cardiologist Helen Taussig (photographed by Karsh in 1975), they developed the Blalock-Thomas-Taussig Shunt, a surgical procedure to relieve the cyanosis from Blue baby syndrome. This operation ushered in the modern era of cardiac surgery.
Blalock was Surgeon-in-Chief at Johns Hopkins Hospital when he was photographed by Karsh. See more images from the Sitting.