Put one-third of a box of gelatin to soak in three cups of cold milk; let soak one-half hour, then place over the fire in a double boiler. Beat the yolks of three eggs until light, add to them one-third cup of sugar, and beat again until light. Put the whites of three eggs into a large bowl, beat to a stiff froth, then stir into the boiling milk the yolks and sugar; stir until it thickens, take from the fire, add one teaspoonful of vanilla, and pour this hot custard over the beaten whites; stir and beat until thoroughly mixed, and pour at once into a mould which has been rinsed out with cold water. Set away at once in a very cold place to harden. Plain or whipped cream may be served with this.