Pero esta magnífica cinta del maestro Howard Hawks contiene una escena mítica en la que Marie "Slim" Browning (Bacall) pone de manifiesto su enorme atractivo y los matices de su personalidad para acabar describiendo, con simplicidad y sensualidad, el procedimiento para silbar. Un atónito Steve Morgan (Bogart) pone en práctica el consejo y esboza una sonrisa burlona.
"You know you don't have to act with me, Steve. You don't have to say anything, and you don't have to do anything. Not a thing. Oh, maybe just whistle. You know how to whistle, don't you, Steve? You just put your lips together and... blow"
