Mixologist Richard Boccato based his Chicago Fizz on the one in Jacques Straub's 1914 Drinks. In addition to having a smooth and silky texture, cocktails shaken with egg whites are alleged to cure (or at least lessen) hangovers.
In a cocktail shaker, combine the rum, port, lemon juice, Simple Syrup and egg white and shake well. Add ice and shake again. Strain the drink into a chilled fizz glass, stir in the club soda and garnish with the orange slice.