Iced Curaçao Soufflé

Put the yolks of five eggs in a stewpan, with six ounces of powdered sugar, beat well together with a wooden spoon; in another stewpan have a pint of milk, in which put an ounce and a quarter of isinglass, boil ten minutes, stirring occasionally to keep it from burning, throw in two sticks of vanilla, take it from the fire, put a cover upon the stewpan till three parts cold, then take out the vanilla, pour the m