[Hearing Callas in Norma in 1952] was a shock, a wonderful shock. You just got shivers up and down the spine. It was a bigger sound in those earlier performances, before she lost weight. I think she tried very hard to recreate the sort of "fatness” of the sound which she had when she was as fat as she was. But when she lost the weight, she couldn't seem to sustain the great sound that she had made, and the body seemed to be too frail to support that sound that she was making. Oh, but it was oh so exciting. It was thrilling. I don't think that anyone who heard Callas after 1955 really heard the Callas voice.