How the Donner Party inspired Charlie Chaplin

Quote from Charlie Chaplin's autobiography:

"In the creation of comedy, it is paradoxical that tragedy stimulates the spirit of ridicule, because ridicule, I suppose, is an attitude of defiance: we must laugh in the face of helplessness against the forces of nature - or go insane. I read a book about the Donner Party, who, on the way to California, missed the route and were snowbound in the Sierra Nevada mountains. Out of 160 pioneers, only 18 survived, most of them dying of hunger and cold. Some resorted to cannibalism, eating their dead, others roasted their moccasins to relieve their hunger. Out of this harrowing tragedy, I conceived one of our funniest scenes. In dire hunger, I boil my shoe and eat it."