Callas as healer

In August 1956, [Franco] Zeffirellli wrote a rather curious note to my wife: “Dear Maria, yesterday evening Marlene Dietrich, one of your rabid admirers, spoke constantly of you. She says that in American hospitals they play your records continuously because they have discovered that your voice helps those who are ill, giving them confidence, calming them, and helping them to recover from what ails them. That is not surprising—we have known that for quite a while.”
Giovanni Battista Meneghini, My Wife Maria Callas