Mix gelatin, sugar, and salt together thoroughly in the top of a double boiler. Beat together the egg yolks and 1 cup skim milk. Add to gelatin mixture and cook over boiling water stirring constantly until gelatin is thoroughly dissolved, about 8 minutes. Remove from heat; add the grated lemon rind; cool. Beat cottage cheese with electric beater until well blended. Stir in gelatin mixture; add lemon juice and vanilla. Chill, stirring occasionally until mixture mounds slightly when dropped from a spoon. Fold in the egg whites, stiffly beaten. Beat the ice-cold water and the nonfat milk together until stiff and mixture stands in peaks. Fold into gelatin mixture. Turn into a 9 inch pan and sprinkle with a mixture of graham cracker crumbs, cinnamon and nutmeg. Chill until firm Yields: 16 servings Individual Serving: 1 3/4 inch wedge = 115 calories