Peel the orange, remove the carpels very carefully and arrange them neatly on a heart of lettuce. Put a saltspoonful of salt and one of sugar, and a tablespoonful of oil into a bowl, put in a piece of ice and stir until the salt and sugar are dissolved; remove the ice and baste the mixture over the orange on the lettuce leaf. Squeeze on top a half teaspoonful of lemon juice, and serve at once.