Soften gelatin in cold water for 5 minutes. Place over boiling water, heat until dissolved. Set aside to cool. Add salt to egg whites and beat with mixer until mixture forms soft peaks. Gradually add sugar a tablespoon at a time, beating until smooth and glossy. Continue beating and add Karo syrup a little at a time, beating thoroughly after each addition, until mixture peaks. Stir and fold the cold gelatin, vanilla and chocolate into whipped mixture. Turn into baked pastry shell. Chill for 3 hours or until firm.