Nothing illustrates this better than her last performance of Orpheus on 3 February 1953. As a result of the radiation treatment she was receiving for cancer, her left femur partially disintegrated while she was on stage. Almost immobile, she sang the remaining arias, and took her curtain calls. She died at University College Hospital on 8 October 1953.
Below are two recordings for which she was particularly well known: Blow the Wind Southerly, and Bach's Erbame Dich from the St Matthew Passion.
Check out also:
Wikipedia: Kathleen Ferrier.
The Kathleen Ferrier Society.