Cut a small-sized, ripe pineapple in two; put one-half away for further use, paring and peeling the other half neatly, then cut it into small pieces; place them in a mortar, and pound them thoroughly to a pulp; ten minutes will suffice for this. Add half a pound of powdered sugar, and pound again for five minutes; transfer the whole into a vessel, squeeze in the juice of three sound lemons, then pour in a quart of cold water, and mix well with the spatula for two minutes. Strain through a fine sieve into the freezer, adding two egg whites, beaten to a stiff froth, then beat well for one minute more. Cover with the lid, and finish it the same as the vanilla ice-cream (No. 68).