Sprinkle gelatin over cold water and let rest until water is absorbed, 5 minutes.
In a bowl, combine gelatin, boiling water, lemon juice and sugar, stirring until sugar is dissolved. Chill in refrigerator, stirring occasionally, until mixture coats the back of a metal spoon.
Beat egg whites until stiff. Beat lemon mixture until frothy. Fold egg whites into lemon mixture until mixture holds together.
