Mash a quart of berries with two cupfuls of sugar, and leave on ice for three hours. Soak for the same time half a package of gelatine in a cupful of cold water. Then pour a cupful of boiling water over the soaked gelatine, and stir over the fire until it is dissolved. Rub the berries through a fine colander, add the dissolved gelatine, and let it get cold. As soon as it is as thick as thin starch, beat into it, gradually, a quart of whipped cream, blending this thoroughly with the other ingredients. Pour into a freezer and freeze.