アスペン音楽祭
From 1947 to 1971, he taught alternate years at Mills and the Paris Conservatoire, until poor health, which caused him to use a wheelchair during his later years (beginning in the 1930s), compelled him to retire. He also taught on the faculty of the Aspen Music Festival and School. He died in Geneva at the age of 81, and he was buried in the Saint-Pierre Cemetery in Aix-en-Provence.