In 1961, at the request of Jefferson Medical College, the Philadelphia Museum of Art (PMA) undertook another restoration, under conservator Theodor Siegl. Mark Tucker, a later PMA conservator, described the work as "a rescue mission... They were saving the painting from tearing itself in half. These were the nail heads that were starting to work forward into the canvas and show as bumps on the front... Yeah. It was just hair-raising." Siegl used a power plane to remove the plywood down to the last, thin ply. The rest of the wood and the tenacious glue were painstakingly removed by hand. Siegl and his colleagues also restored, to some extent, the faces in the upper right of the canvas.