Dissolve the gelatine in a half cup of cold water, then add boiling water, one and a half Cupfuls of milk, a teaspoonful of Vanilla, and, when nearly cool, add one cup of powdered white sugar and the juice of one lemon. Beat well and lightly. When cold, beat as white as snow, and add the whites of the eggs, beaten to a stiff froth. Beat all thoroughly, and pour into a mold. Stand in a cold place for four hours to harden. Make a Custard Sauce by beating the yolks of the eggs together with a half cup of sugar till very light. Stir them into one and a half cups milk, which should be boiling. Let cook, stirring constantly, for two or three minutes. Then add a teaspoonful of Vanilla, and set to cool. Serve with the Pudding, pouring the sauce upon it.